SETI always makes us ask what human-centered assumptions we are making about extraterrestrial civilizations. When it comes to detecting an actual technology, like the starships we’ve been talking about in the last two posts, we’ve largely been forced to study concepts that fit our understanding of physics. Thus Robert Zubrin talks about how we might detect a magsail, or an antimatter engine, or a fusion-powered spacecraft, but he’s careful to note that the kind of concepts once studied by the Breakthrough Propulsion Physics Project at NASA may be undetectable, since we really don’t know what’s possible and what its signature might be.
I mentioned zero-point energy in a previous post because Zubrin likewise mentions it, an idea that would draw from the energy of the vacuum at the quantum level. Would a craft using such energies — if it’s even possible — leave a detectable signal? I’ve never seen a paper on this, but it’s true that one classic paper has looked at another truly exotic mechanism for interstellar travel, the wormhole. These shortcuts through spacetime make space travel a snap. Because they connect one part of the universe to another, you go in one end and come out the other, emerging into another place and, for all we know, another time.
The fact that we don’t know whether wormholes exist doesn’t mean we can’t think about how to detect one, although the authors of the classic paper on wormhole detection make no assumptions about whether or not any intelligent species would actually be using a wormhole. The paper is “Natural Wormholes as Gravitational Lenses,” and it’s no surprise to find that its authors are not only wormhole specialists like Matt Visser and Michael Morris, but physicists with a science fiction connection like John Cramer, Geoffrey Landis, Gregory Benford and the formidable Robert Forward.
Image: A wormhole presents a shortcut through spacetime. Can one be detected? Credit: Wikimedia Commons.
The analysis assumes that the mouth of a wormhole would accrete mass, which would give the other mouth a net negative mass that would behave in gravitationally unusual ways. Thus the GNACHO (gravitationally negative anomalous compact halo object), which playfully echoes the acronym for massive compact halo objects (MACHOs). Observationally, we can look for a gravitational lensing signature that will enhance background stars by bending light in a fundamentally different way than what a MACHO would do. And because we have MACHO search data available, the authors propose checking them for a GNACHO signature.
In conventional gravitational lensing, when a massive object moves between you and a much more distant object, a greatly magnified and distorted image of the distant object can be seen. Gravitational lensing like this has proven a useful tool for astrophysicists and has also been a means of exoplanet detection. But when a wormhole moves in front of another star, it should de-focus the light and dim it. And as the wormhole continues to move in relation to the background star, it should create a sudden spike of light. The signature, then, is two spikes with a steep lowering of light between them.
The authors think we might find the first solid evidence for the existence of a wormhole in our data by looking for such an event, saying “…the negative gravitational lensing presented here, if observed, would provide distinctive and unambiguous evidence for the existence of a foreground object of negative mass.” And it goes without saying that today’s astronomy, which collects information at a rate far faster than it can be analyzed, might have such evidence tucked away in computer data waiting to be discovered by the right search algorithms.
Would a wormhole be a transportation device? Nobody knows. Assuming we discover a wormhole one day, it would likely be so far away that we wouldn’t be able to get to it to examine its possibilities. But it’s not inconceivable that a sufficiently advanced civilization might be able to create an artificial wormhole, creating a network of spacetime shortcuts for instantaneous travel. Matt Visser has discussed a wormhole whose mouth would be held open by negative energy, ‘…a flat-space wormhole mouth framed by a single continuous loop of exotic cosmic string.’ A primordial wormhole might survive from the early universe. Could one also be created by technology?
Civilizations on the Brink
More conventional means of transport like solar or laser-powered sails present serious problems for detection. In Jerry Pournelle and Larry Niven’s The Mote in God’s Eye, an alien lightsail is detected moving at seven percent of the speed of light, its spectrum the same as the star that it is approaching but blueshifted, which is how analysts have determined it is a sail. The novel’s detection occurs with far more sophisticated observatories than we have in our day, when finding a solar or lightsail in transit would be a tricky thing indeed. A fusion rocket, for example, would emit largely in the X-ray range and could be detectable for several light years, but a lightsail is a highly mutable catch.
I remembered reading something about this in Gregory Matloff’s Deep Space Probes (Springer, 2005) and checked the book to extract this:
If ET prefers non-nuclear travel, he might utilise a laser or maser light sail. If the starship is near enough and the laser/maser is powerful enough, reflections from the sail might be observable as a fast-moving and accelerating monochromatic ‘star.’ However, detection will depend on sail shape and orientation as well as other physical factors.
Therefore, it is not as easy to model the spectral signature of these craft as it is energetic nuclear craft. A starship accelerated using lasers or masers may be easier to detect during deceleration if a magsail is used.
Writing in the comments to yesterday’s post, Centauri Dreams reader James Jason Wentworth recalls Larry Niven’s short story “The Fourth Profession,” which has a lightsail detection something like the one in The Mote in God’s Eye:
“All right. The astronomers were studying a nearby nova, so they caught the intruder a little sooner. It showed a strange spectrum, radically different from a nova and much more constant. It got even stranger. The light was growing brighter at the same time the spectral lines were shifting toward the red.
“It was months before anyone identified the spectrum.
“Then one Jerome Finney finally caught wise. He showed that the spectrum was the light of our own sun, drastically blue-shifted. Some kind of mirror was coming at us, moving at a hell of a clip, but slowing as it came.”
Some sails could be truly gigantic, and we can imagine worldships large enough to require sails the size of a planetary radius, which could be detected when near their home or destination stars, but would be hard to find when in cruise. Matloff goes on to suggest that any search for this kind of ship should look near stars from which an entire civilization might be emigrating. A star like Beta Hydri is a possibility, a nearby (21 light years) solar-type star now expanding from the main sequence. This is the longest shot of all, but finding unusual signatures in visible light near a star leaving the main sequence would at least compel a second look.
The wormhole paper is John Cramer, Robert L. Forward, Gregory Benford et al., “Natural Wormholes as Gravitational Lenses,” Physical Review D (March 15, 1995): pp. 3124-27 (available online). See also Matloff and Pazmino, “Detecting Interstellar Migrations,” in Astronomical and Biochemical Origins and the Search for Life in the Universe, ed. C. B. Cosmovici, S. Bowyer and D. Werthimer, Editrici Compositori, Bologna, Italy (1997), pp. 757-759.
“Sorry I was not clear. I did not mean to say that it made no sense to accelerate the pellet. I meant to say it is unnecessary for the pellet to be fuel. It could be anything at all, because its kinetic energy is as large as any nuclear energy it could produce.”
Using the kinetic energy of particles has several inconveniences:
-it can only accelerate; it can’t decelerate the starship;
-it imparts significant momentum when the ship has a small velocity; as the ship’s velocity increases, the imparted momentum decreases quadratically (the kinetic energy of particles remains high ONLY from the mass-driver’s stationary POV);
-for a ship, kinetic projectiles have only the propulsion; fuel pellets are far more versatile, satiating the ship’s energy requirements. If you send matter to the ship at a large energy/infrastructure cost, you should make this matter as useful as possible.
As for using light – it’s the worse option:
-diffraction – you need megaengineering to focus the beam;
-far higher energy consumption for the same momentum – by comparison to heavier/slower particles. It’s even more energy hungry than your nuclear rocket.
@Avatar: You are right about the rocket, I missed a decimal there. It did seem too good to be true. Nevertheless, the approach still works. It does leave, however, considerably less room for inefficiencies if 0.2c is the goal.
StarTram is a wonderful design, I like it a lot. It does not go much into the details of magnetic acceleration, though. See this paper for more on that, including a decent treatment of some serious limitations: scorevoting.net/WarrenSmithPages/homepage/launcher.ps
Kare’s lightsails are another design I admire. However, I think you missed that Kare recognizes the impossibility of aiming passive lightsails, and proposes to outfit them with active guidance systems. After clearing this up (unless I am mistaken, again?), I await your suggestions as to deal with this issue in your concept.
You may be right about the 600K, and I am a fan of lithium deuteride fuel myself. That part might just work.
By the way, the formula for power to be pumped into the projectile is P = m*v*a, where v is the velocity and a the acceleration. For v = 0.1 c and a = 1,000,000 g (the constant acceleration hat allows your mass driver to be “only” 45,000 km long) this comes to 3*10^14 W/kg. I leave it as an exercise to the reader to calculate how many microseconds it will take for the projectile to vaporize if the EM-to-kinetic conversion efficiency is 99%.
I don’t think so. This would be a unheard-of piece of accelerator engineering. How are you going to get all the particles to the same place in space and time, with Angstrom precision and velocities matched to room temperature or below? All this while they are travelling at 0.1 c? Please….
If you try to charge 1000 atom clusters, you will get a distribution of clusters with charges of -1, -2, -3, etc. You can only accelerate one kind per shot, and I do not think you will get much beyond -3 or so, as the clusters will disintegrate from electrostatic repulsion. Plus, you have to ensure that the clusters do not pick up or lose a single electron or atom while they are being accelerated (that would be a few seconds, I believe). Even if you could do it, 1000 atom clusters are not a lot of payload, you are seriously up against Avogadro here (10^23).
At 3 orders of magnitude (which I think is optimistic), you get a circumference of 27,000 km, which is not too far off the 45,000 km we discussed earlier. It is also not much smaller than the Earth, so, yes, I do think it qualifies for the mega label. 27,000 km of superconducting magnets will also be pretty expensive. And, in addition, the electric fields in the resonators for acceleration will have to be the same 3 orders of magnitudes stronger, which I doubt is possible at all.
Eniac
It is time for an upgraded general presentation of the accelerator/ship system:
THE ACCELERATOR:
Let us take an accelerator that uses RF (changing electric fields)* for acceleration and the Lorentz force for turning the accelerated atoms around.
The circumference of a circular accelerator – tentatively, established at 2000 km.
Why so small? Soon to be explained:
The accelerator is to be cut in half (each half of 1000 km). The two pieces moved apart at a considerable distance – some millions of kilometers apart.
Both half-circles are to be made of large superconducting magnets.
When the fissionable/fusionable atoms reach one half-circle, they will be turned around by the Lorentz force – today, we know (at least in theory) how to generate strong enough magnetic fields for this performance.
The actual acceleration of atoms will take place in the empty space between the half-circles, by RF.
When I looked up the RF LHC uses, their small size was surprising. An RF superconducting cavity is not longer than 4-5 meters, and per beam there are 8 cavities (LHC has 16 cavities in total, for its two beams!):
http://upload.wikimedia.org/wikipedia/commons/e/ec/LHC_RF_cavity_in_the_testing_hall.jpg
The small size these RF cavities means:
One can easily increase their performance by 2 orders of magnitude by just making them larger (making the superconducting magnets 100 times thicker/etc); Increasing their performance by even 4 orders of magnitude should be feasible;
Let us say the two half-circles are put 5400000 kilometers apart; Also, we will put clusters of 8 RF chambers separated by 2,25 kilometers.
The number of the RF chambers will be quite large, but their size remains small – the construction would not qualify as megaengineering (unless you mean a very timid such feat).
The LHC – at full capacity, its beam pipes contain 1*10-9 grams of hydrogen; and they are accelerated to 0,999…c in 20 minutes:
http://en.wikipedia.org/wiki/Lhc
The kinetic energy of a particle at 0,1c is 7*10p5 smaller than a particle having only 3 m/s less than the speed of light (as the LHC has). Meaning, you can accelerate to 0,1c 7*10p5 more mass than the LHC does at 0,999…c with the same technology/limitations.
The length/RF increase in performance makes the half-circles accelerator 24*10p5 more powerful than the LHC.
All this means the half-circles accelerator can accelerate 168*10p6 grams every 20 minutes.
Take that, Avogadro!
ACCELERATED FUEL:
It would be composed of atoms/molecules – lithium deuteride of fissionable atoms.
It would be accelerated to 0,1c by the accelerator.
After the fuel exits the half-circles, it will be made electrically neutral. After a few light-minutes to light-hours, it will encounter stations whose purpose is to focus the beam (cancelling the slight diffraction) and correct the trajectory of atoms/molecules incorrectly targeted (collimation).**
THE SHIP:
It will be able to detect the incoming beam and maneuver to meet it (a few hundred km). Considering that it has nuclear-powered thrusters, this should be easy enough.
The ship will charge positively the incoming fuel; The ship will be equipped with a strong positive electrostatic field, meant to align the velocity of the fuel to the velocity of the ship
During acceleration:
Both the kinetic energy AND its nuclear energy will be used – via electrostatic field and nuclear engines.
During deceleration:
This time, the electrostatic interaction will cancel itself, the ship being propelled only by the nuclear energy of the fuel.
*Mass drivers (changing magnetic field propulsion) should be able of the same performances, if it were to accelerate atoms/molecules. I chose RF simply because we already have experimental confirmation for it with the LHC.
**If the trajectories of atoms/molecules prove more difficult to control, you can coalesce them into macroscopic pellets in the following manner:
A few light-hours after the accelerator, the atoms/molecules from a single packet/bucket will have sorted themselves out – the faster ones ones will be ahead, the slower ones behind. The difference in velocity between two neighboring atoms/molecules should be at room temperature levels.
At this point, the atoms/molecules will be heated until they reach their melting temperature and them pressed together – all these sideways from the direction of motion of the atoms/molecules.
PS – About Startram – one can easily build a far smaller mass-driver to launch cargo into orbit. The 1200 km long version is for an acceleration acceptable to people (with no special training).
Error correction:
“The LHC – at full capacity, its beam pipes contain 1*10-9 grams of hydrogen; and they are accelerated to 0,999…c in 20 minutes:
http://en.wikipedia.org/wiki/Lhc
The kinetic energy of a particle at 0,1c is 7*10p5 smaller than a particle having only 3 m/s less than the speed of light (as the LHC has). Meaning, you can accelerate to 0,1c 7*10p5 more mass than the LHC does at 0,999…c with the same technology/limitations.
The length/RF increase in performance makes the half-circles accelerator 24*10p5 more powerful than the LHC.
All this means the half-circles accelerator can accelerate 168*10p6 grams every 20 minutes.”
That would be:
The kinetic energy of a particle at 0,1c is 14*10p5 smaller than a particle having only 3 m/s less than the speed of light (as the LHC has). Meaning, you can accelerate to 0,1c 14*10p5 more mass than the LHC does at 0,999…c with the same technology/limitations.
The length makes the half-circles accelerator 12*10p5 more powerful than the LHC (with the same type of RF used).
All this means the half-circles accelerator can accelerate 168*10p6 grams every 20 minutes (without increasing RF performance).
If one increases the RF performance by making them bigger, the accelerated mass would grow, but only at the expense of the accelerator being megaengineering.
Other:
I made the accelerator 5400000 kilometers long, but most of it is empty space.
Why?
Because I imagine it will be built in stages; first, the minimum necessary (for 0,1c interstellar travel): afterwards, other RF will be added across decades/centuries, increasing its performance.
Other problems with the accelerator would be power distribution and keeping the substations of the accelerator from drifting due to force reaction.
About power distribution – the generators should be located near mining sites – for lowering transport costs. Power should be transmitted in EM wave form to the generator (yes, I know that, as of today, such power transfer is inefficient; but that is a problem theoretically solvable).
About the generator subsections maintaining a constant position relative to each other – there are a few feasible solutions, from lightsails to thrusters.
This is starting to be an interesting project. By suggesting the use of atoms instead of pellets you have indeed opened up the possibility of relativistic mass transfer in the form of a particle beam. A few problems remain, though, foremost being the collimation issue.
Let me point out a few areas that I believe need more work:
1) You are assuming that the electric field strength in the RF resonators scales up with size and/or wall thickness. I don’t think either is the case, you should substantiate this claim.
2) You are assuming that lower final energy will permit a proportional increase in beam current. I do not think this is the case, you should substantiate this claim.
3) You are assuming that there will not be problems with keeping the beam focused as the two halves are separated from each other by an enormous distance. I think there will be problems, and you should look into that.
4) You are proposing to correct the transverse position of individual atoms to drift less than 100 km per year (0.003 m/s). This corresponds to a temperature of 100 nano-Kelvin, assuming a particle mass of 250 amu (http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/eqpar.html#c2). You should consider if that is feasible, especially in the face of perturbations from external fields and other effects. Even the minutest effects would throw the atoms of course. Note that even neutral atoms are subject to electromagnetic fields as exist in space. Small ones, yes, but that is all it takes.
5) You should propose some sort of mechanism for the ship to collect all incoming particles in a 100km wide field, and channel them to a central engine. If I read you correctly, you propose that the ship will actively chase individual atoms within this range. I must have misunderstood, this notion is just too absurd. Perhaps you are assuming instead that the beam is much narrower than 100km, which would, of course, make collimation even more difficult (point 4). If you can manage a 1 km capture aperture at the ship, you need a transverse velocity of less than 0.00003 m/s, or 10 pico-Kelvin.
6) You are proposing to neutralize and then recharge the particles multiple times while they are being accelerated, and you are assuming that this is possible without significant losses and while maintaining the 0.003 m/s (or 0.00003 for the 1k aperture) limit on transverse velocity after the last neutralization. This would require an exceptionally gentle neutralization process. You should elaborate on how you would go about this.
7) You propose to refocus the neutral particles a few light minutes or hours from the accelerator. You did not specify whether the atoms are to be charged and neutralized again at this point, or how else you are going to correct their course.
8) You propose to send on the order of 10^20 (roughly, give or take a few orders) atoms per second. You should consider whether the per-atom course adjustments that you are proposing for the collimation could really be scaled up to this frequency.
9) I am not sure there is anything to be gained by pulling the accelerator apart as you propose. It is not obvious how the maximum throughput of the device (aka beam current) would increase as the distance between the two halves gets larger, but the magnets and RF resonators remain unchanged. I would think that keeping the accelerator compact and increasing the maximum beam current that the magnets and RF resonators can support would work much better. I am sure the LHC was optimized for beam current, so much work has likely gone into this problem. As far as I know, empty space between the magnets and resonators is of no benefit. To the contrary, I think it reduces the aperture of the “optics” and thereby the maximum supportable beam intensity.
I hope that these points may help you refine your design, although I will be frank in saying that I think you still have very far to go before this can become even remotely feasible. It is no accident that particle beams have not been discussed much for space propulsion.
Let me clarify on point 9): I understand you do want to put more RF accelerators, not only empty space. However, it is hard for me to see how the throughput (aka beam current) can be increased by putting more devices in series. Putting several accelerators in parallel seems like the better approach, here.
Yes, of course.
See the paper I cited (http://scorevoting.net/WarrenSmithPages/homepage/launcher.ps) for an interesting proposal that is much shorter. He also has a very interesting section on “Previous techniques and ideas for reaching high speeds”, where he rips into all sorts of mass drivers. Very relevant for the subject at hand, even though “high speeds” here means around 0.00003 c, only.
Eniac
The RF capability I start with is the one LHC’s RFs have now. This is highly conservative (an increase of an order of magnitude is possible, and to be expected).
The LHC has 16 RFs.
I calculated the total kinetic energy they give to the atoms in the LHC’s beam tubes in 20 minutes (when they accelerate these atoms to 3 m/s less than the speed of light).
By giving the exact same total kinetic energy, these 16 RFs can accelerate 14*10p5 more atoms to 0,1c.
Modifications in the RFs geometry may be in order, for the larger (diameter-wise) beam to be able to pass through their middle; that’s about it.
I made the accelerator oval-shaped in order to be able to add new RFs (and other components) to it across the decades/centuries.
Naturally, at first one could make the accelerator shorter – between the two-circles (which could even be smaller than 1000 km each – LHC is only 27 km long), existing only the RFs (and other components) and no empty space.
As for focusing the beam in the accelerator, this can be done with magnets placed at regular intervals (as with the LHC).
I propose to neutralize the atoms once, when they exist the accelerator, and then electrostatically charge them once, when they’re near the ship.
COLLIMATION
Departure from the accelerator.
As for the stations that are located a few light-minutes or light-hours away from the accelerator, they could use either changing magnetic fields or changing electric fields to correct the trajectory of the atoms.
The number of atoms is a problem only if you want to assess and correct the trajectory of each one, individually.
I am thinking at using an area strategy: after a few light-minutes/light-hours, the precisely targeted at0ms will be on course; the incorrectly targeted ones will follow a cone-like trajectory.
As such, the changing magnetic/electric fields of the stations will impart no sideways motion to the center of the atom beam. They will impart an increasingly large sideways motion to the ring-shaped areas, as these areas are further away from the center of the beam.
Arrival at the ship:
Before the fuel reaches the ship, it will deploy probes that will take position a few light-seconds behind the ship.
These probes will detect the position of the fuel atoms beam ( which now is, presumably, a ~100-200 km wide beam). The probes will send the information about the position of the fuel atoms beam to the ship.
The ship will charge the fuel (with a positive electrostatic charge), using the information received from the probes, while the fuel is light-seconds away.
The probes will be charged with a negative electrostatic field and will be previously positioned in locations calculated so as to focus the fuel atoms beam to a central point (their negative electrostatic field will only be strong enough to give relatively small sideways motions to the fuel atoms).
After a few light-seconds of travel, the fuel atoms beam will reach this central point, where the ship will have positioned itself.
The fuel will be gathered by the ship by using an positive electrostatic field (strong enough to stop the fuel atoms from 0,1c to the ship’s velocity).
Eniac
In this post, I want t0 touch on the potential for my approach to interstellar travel.
Let’s say we have fission fuel and can make it have an effective exhaust velocity of 0,02c (we’re almost there today).
And the ship does NOT need to carry this fuel on-board.
This means that only 1000 tonnes of fuel can give a delta v of 0,2c to a ship 100 tonnes heavy.
And, as I have shown above, my accelerator can accelerate 168*10p6 grams to 0,1c (this is the fuel’s accelerated velocity required for a delta v of 0,2c) every 20 minutes.
168*10p6 grams = 168 tonnes every 20 minutes!
This opens the way to interstellar ships not only 100 tonnes heavy, BUT 1000s of tonnes heavy:
Massive colonization ships, carrying thousands of colonists; commercial ships, carrying vast amounts of valuable cargo; etc
It may even open the door to ships that travel not only with 0,1c (delta v = 0,2c), but with 0,2 – 0,4c.
Compare and contrast this with a 60 tonnes toy nuclear rocket that must carry 7500000 tonnes of fuel on board for a delta v of 0,2c – a strategy that will ensure the only interstellar travel will be limited to scientific expeditions and automated probes.
The difference in potential is blindingly obvious.
Avatar: Nobody doubts that if mass/energy/momentum transfer over interstellar distance could be achieved it would have a lot of potential. So, yes, the potential is obvious.
In this new incarnation you are essentially suggesting an accelerator, two lenses, and the ship, where the accelerator is at the focus of one lens, and the ship at the focus of the other.
You need the transverse velocity of the atoms to be controlled to within 0.003 m/s, or 100 nano-Kelvin. You have not said how you are going to discharge and charge the atoms, but please note that the energy involved in such processes is around 1 eV, quite a number of orders of magnitude greater than what would be needed to “bump” the atoms more than 0.003 m/s.
You have proposed one of the lenses to act on neutral atoms, the other to be effected by point charges. You envision them to be 100 km in diameter, if I understand correctly. I suppose you should say something more specific about the design of these lenses. A 100 km lens able to accurately focus neutral atoms is difficult to imagine, and point changes are not suitable for focussing charged particle beams. To effect a focus, more distant atoms need to be deflected more, less distant ones less. Point charges do just the opposite.
You expect the accelerator to have a throughput of 168 tons per 20 minutes, or roughly 150 kg/s. I encourage you to calculate the beam current corresponding to this in Amperes, assuming a single charge on Uranium atoms. It will give you an idea about how much current the accelerator and the charge/discharge units will have to handle. I predict it will not be pretty.
Avatar:
I’d say. You have upgraded the throughput from 10^-9 grams to 168 tons per 20 minutes.
Sure, piece of cake. Only 17 orders of magnitude.
:-)
Eniac
THE INAUGURAL VOYAGE WITH THE ACCELERATOR
The first ship will be specialized – it will carry hundreds/thousands of probes meant to focus the fuel atoms beam. It will deploy them every 1/10 of a light year (40 stations to Alpha Centauri), perhaps even denser. This ship will be given more fuel by the accelerator than a ship of its mass (~1000 tonnes) would normally receive – in order to give the probes the fuel necessary to come to a stationary position.
At every drop station will be deployed 1-3 probes meant to scan the atom beam and calculate the necessary positions for the other probes. The other probes (5-10 in number) will focus the fuel pellets by changing magnetic/electric fields (the diameter of the circle/oval form they will be deployed in should be no more than hundreds of meters).
These probes will be given energy by passing ships via EM beams (the same technology that transports energy from mining sites to the accelerator).
As to the problems outlined by you, Eniac:
“[Redesigning RF geometry] Sure, piece of cake. Only 17 orders of magnitude.”
It is, indeed, a piece of cake. One of the obviously solvable problems – redesigning the GEOMETRY of something, not its power capacity, etc. And this geometry doesn’t have to be 17 orders of magnitude larger; not even close:
The reason the half-circes accelerator can accelerate so much more matter than the LHC is because:
1 – it only accelerates the particles to 0,1c, NOT to 0.999999991 c (as the LHC does) – in order to compensate for this, the RF geometry must be redesigned;
2 – it’s longer than the LHC (aka more particle bunches fit in at the same time) and the particle bunches are accelerated throughout its length, not only at a single segment (as with the LHC) – this doesn’t call for a redesign for the RFs (not a major one, anyway).
“You have not said how you are going to discharge and charge the atoms, but please note that the energy involved in such processes is around 1 eV, quite a number of orders of magnitude greater than what would be needed to “bump” the atoms more than 0.003 m/s.”
And? This energy grows linearly with the number of atoms charged/discharged.
Even today we have solutions to charge/discharge atoms. They will be scaled up. When it comes to interstellar travel (ANY type of it), the energy needed to ‘“bump” the atoms ~0.003 m/s’ is small by comparison.
This is yet another obviously solvable problem.
“You have proposed one of the lenses to act on neutral atoms, the other to be effected by point charges. You envision them to be 100 km in diameter, if I understand correctly.”
The first lens (more like a ring, actually, generating changing magnetic/electric fields) will be tens of meters in diameter (hundreds at most) – when it exists the accelerator, the particle beam will have a diameter of ~meters, at most.
I explained above the mechanism for its functioning – note that it is not definitive; there are alternate strategies that may turn out to be more efficient – see the sailbeam proposal or Singer, C. E., “Interstellar Propulsion Using A Pellet Stream For Momentum Transfer”.
The second lens:
Original design (from my previous post):
It will not be a lens – more like 5-10 probes, negatively charged***, arranged in a circular/oval-shaped form (depending on the shape of the fuel particle beam when it reaches the ship)*, whose purpose it to impart a small sideways momentum to the fuel atoms so the atoms**, traveling forward at 0,1c. will “meet” after a few light-seconds of travel.
*the shape of the fuel particle beam will have already been scanned, by these probes or by another specialized probe
**aka – the resultant momentum imparted to the fuel atoms in the center of the beam will be 0, the one imparted to the atoms slightly sideways larger, etc.
The second design (after we have stations every 1/10 light years):
Now, these probes may very well use themselves changing magnetic/electric fields to focus the beam; they will located in a circular/oval-shaped form – now, at most, ~hundreds of meters (NOT km) in diameter.
Now, the fuel atoms will be charged only when they’re near the ship, in order to be stopped by the ship’s positive electrostatic field.
These lenses are also a solvable problem – Eniac, yes, fine tunning engineering is required to make them work properly. Fine tunning is eminently doable.
“I encourage you to calculate the beam current corresponding to this in Amperes, assuming a single charge on Uranium atoms. It will give you an idea about how much current the accelerator and the charge/discharge units will have to handle. I predict it will not be pretty.”
For a ship 100 tonnes heavy with an effective exhaust velocity of 0,02c, for a delta v of 0,2c:
Using my accelerator, the energy expended will be: 1000 tonnes fissionable/fusionable fuel (in generated energy) + kinetic energy (1000 tonnes * 0,1c^2) + what is expended to charge/discharge the fuel ( a term smaller, by far, than the previous two terms) + thermodynamic losses.
Using a standard nuclear rocket, the energy expended will be 2220000 tonnes (in generated energy) + thermodynamic losses.
Care to redo this calculations for a ship 1000 tonnes heavy? Or 10000 tonnes heavy?
The energy expended by the nuclear rocket makes the energy expended by the accelerator look trivial, Eniac.
Plus, the accelerator can be used to send THOUSANDS of ships, many even at the same time; the nuclear rocket, on the other hand, is strictly one-use.
You once said “I would have to answer with a resounding: The nuclear rocket, of course!”
Considering that the nuclear rocket is an impractical toy by comparison to the accelerator, a resounding ‘the accelerator is, by a huge margin, the better option!’, is in order.
Eniac
THE INAUGURAL VOYAGE WITH THE ACCELERATOR
The first ship will be specialized – it will carry hundreds/thousands of probes meant to focus the fuel atoms beam. It will deploy them at every 1/10 light year (40 stations to Alpha Centauri), perhaps even denser. This ship will be given more fuel by the accelerator than a ship of its mass (~1000 tonnes) would normally receive – in order to give the probes the fuel necessary to come to a stationary position.
At every drop station will be deployed 1-3 probes meant to scan the fuel atoms beam and calculate the necessary positions for the other probes. The other probes (5-10 in number) will focus the fuel atoms beam by changing magnetic/electric fields* (the diameter of the circular/oval-shaped form they will be deployed in should be no more than ~hundreds of meters).
These probes will be given energy by passing ships via EM beams (the same technology that transports energy from mining sites to the accelerator).
The starway will be maintained by specialized ships traveling it every few decades, replacing defective probes, etc.
As to the problems outlined by you, Eniac:
“[Redesigning RF geometry] Sure, piece of cake. Only 17 orders of magnitude.”
It is, indeed, a piece of cake. One of the obviously solvable problems – redesigning the GEOMETRY of something, NOT its power capacity, etc. And this geometry doesn’t have to be 17 orders of magnitude larger; not even close:
The reason the half-circles accelerator can accelerate so much more matter than the LHC is because:
1 – it only accelerates the particles to 0,1c, NOT to 0.999999991c (as the LHC does) – in order to compensate for this, the RF geometry must be redesigned in order to admit a thicker fuel atoms beam;
2 – it’s longer than the LHC (aka more particle bunches fit in at the same time) and the particle bunches are accelerated throughout its length, not only through a single segment (as with the LHC) – this doesn’t call for a redesign for the RFs (only for more of them).
“You have not said how you are going to discharge and charge the atoms, but please note that the energy involved in such processes is around 1 eV, quite a number of orders of magnitude greater than what would be needed to “bump” the atoms more than 0.003 m/s.”
And? This energy grows linearly with the number of atoms charged/discharged.
Even today we have solutions to charge/discharge atoms. They will be scaled up. When it comes to interstellar travel (ANY type of it), the energy needed to ‘“bump” the atoms to ~0.3 m/s’ is all but trivial.
This is yet another obviously solvable problem.
“You have proposed one of the lenses to act on neutral atoms, the other to be effected by point charges. You envision them to be 100 km in diameter, if I understand correctly.”
The first lenses (more like rings, actually, generating changing magnetic/electric fields) will be tens of meters in diameter – when it exits the accelerator, the particle beam will have a diameter of ~meters, at most.
I explained above the mechanism for its functioning*.
The second lens:
Original design (from my previous post):
It will consist of 5-10 probes, negatively charged, arranged in a circular/oval-shaped form (depending on the shape of the fuel atoms beam when it reaches the ship)**, whose purpose is to impart a small sideways momentum to the fuel atoms so that the atoms***, traveling forward at 0,1c. will “meet” after a few light-seconds of travel.
The second design (after we have stations every 1/10 light years):
Now, these probes may very well themselves use changing magnetic/electric fields to focus the beam; they will be located in a circular/oval-shaped form – now, at most, ~hundreds of meters (NOT km) in diameter.
Now, the fuel atoms will be charged only when they’re near the ship, in order to be stopped by the ship’s positive electrostatic field.
The ‘lenses’ are also a solvable problem – Eniac, yes, fine tuning engineering is required to make them work properly. And fine tuning is eminently doable.
“I encourage you to calculate the beam current corresponding to this in Amperes, assuming a single charge on Uranium atoms. It will give you an idea about how much current the accelerator and the charge/discharge units will have to handle. I predict it will not be pretty.”
For a ship 100 tonnes heavy with an effective exhaust velocity of 0,02c, for a delta v of 0,2c:
Using my accelerator, the energy expended will be: 1000 tonnes fissionable/fusionable fuel (in generated energy) + kinetic energy (1000 tonnes * 0,1c^2) + what is expended to charge/discharge the fuel (a term smaller, by far, than the previous two terms) + thermodynamic losses.
Using a standard nuclear rocket, the energy expended will be 2220000 tonnes (in generated energy) + thermodynamic losses.
I encourage you to redo these calculations for a ship 1000 tonnes heavy. Or 10000 tonnes heavy.
The energy expended by the nuclear rocket makes the energy expended by the accelerator look trivial, Eniac.
Plus, the accelerator can be used to send THOUSANDS of ships, many even at the same time (depending on the amount of fuel the accelerator accelerates); the nuclear rocket, on the other hand, is strictly one-use.
*note that the functioning mechanism for the ‘lenses’ is not definitive; there are alternative strategies that may turn out to be more efficient – see the sailbeam proposal or Singer, C. E., “Interstellar Propulsion Using A Pellet Stream For Momentum Transfer”.
*the shape of the fuel atoms beam will have already been scanned, by these probes or by other specialized probes.
**aka – the resultant momentum imparted to the fuel atoms in the center of the beam will be 0, the one imparted to the atoms slightly sideways larger, etc.
You once said “I would have to answer with a resounding: The nuclear rocket, of course!”
Considering that the nuclear rocket is an impractical toy by comparison to the accelerator, a resounding ‘The accelerator is, by a huge margin, the better option!’, is in order.
Eniac
“Only 17 orders of magnitude.”
Without increasing the RF’s performance at all, with an accelerator 200000 km total length (an oval with the length of 100000 km*), we can launch ships 100 TONNES HEAVY (we can launch 91,98 tonnes of fuel per year at 0,1c).
I discussed primarily this variant in the above posts.
If the RF’s performance can be increased by 1 order of magnitude (doable), with an accelerator 200000 km total length (an oval with the length of 100000 km), we can launch ships 1000 TONNES heavy – or launch ships 100 tonnes heavy with an accelerator 20000 km total length.
If the RF’s performance can be increased by 2 orders of magnitude (maybe doable), with an accelerator 200000 km total length (an oval with the length of 100000 km), we can launch ships 10000 TONNES heavy.
If the RF’s performance can be increased by 3 orders of magnitude (not a priori impossible), with an accelerator 200000 km total length (an oval with the length of 100000 km), we can launch MASSIVE ships 100000 TONNES heavy.
*Megaengineering? Yes, but on the small side of the scale – doable, for a civilization that has access to the riches of the entire solar system. Also, note that the accelerator is modularly built; its length can be increased across the decades/centuries.
Eniac
Error correction:
“You expect the accelerator to have a throughput of 168 tons per 20 minutes”
I was too optimistic in proposing this figure, indeed.
The current figure is 3,5 kg per 20 minutes AKA 91,98 tonnes per year (using RFs with NO improvements in capability over the ones we have today).
“THE INAUGURAL VOYAGE WITH THE ACCELERATOR
The first ship will be specialized […] its mass (~1000 tonnes) [..].”
The mass of the first ship should be ~100 tonnes, NOT ~1000 tonnes.
PS:
My first 2 posts (fro this batch) are duplicates. Please read the second – the first was posted due to an accident before several corrections.
I think you have misunderstood my point. Sorry I was not clear. The trick is NOT to bump the atoms by more than 0.003 m/s while adding or abstracting an electron. If you do, they will diverge from the beam too much to make their next rendezvous with a station. This is difficult, because the energy required to add or abstract an electron is many orders of magnitude greater than that required to bump the atoms off the beam.
And you still have not said HOW you are going to do the charging and discharging. The methods we have today involve sending the beam through a foil of some sort. They involve losses, and mess with collimation. At the mass throughput you propose, even a 1 m thick block of lead would instantly evaporate, without providing much charging or discharging. S, I think “scale them up” is not the right answer. You have to come up with some sort of mechanism that is at least remotely credible. See below for the magnitude of the charging/discharging current that needs to be sourced or sunk.
I do not know what your definition of a lens is. To me, an apparatus whose purpose it is to focus incoming parallel tracks into a point is a lens. And 5-10 charged probes are not going to accomplish that under any circumstances. I think what you need is a concentric grid of circular charged wires, with the voltage between successive circles increasing outwards.
So now we have tightened the transverse velocity requirement even further. No atom can have a transverse velocity of more than 100 m per 1/2 year (time it takes the beam to travel between stations) compared to the rest of the beam, or else it will miss the next station. This computes to 0.0003 m/s, or 1 nano-Kelvin. In case you do not realize: This is impossibly low, ridiculously so. The famous cosmic microwave background radiation alone is 4 K. It will interact with your beam to heat it up beyond the required 1 nano-Kelvin in, oh, I don’t know, microseconds, maybe? If you can ever get it that cold to begin with, which is a preposterous proposition by itself.
You have not done the calculation on the beam current that I recommended, so I will help you out: At the throughput of 150 kg/s which you have claimed, Uranium atoms with a single charge constitute a current of roughly 100 mega-amperes. This current needs to be provided at the accelerator ion source, and anywhere there is charging and discharging of the beam. The current has to come from somewhere, too. In space (especially interstellar), there is no ground. The size of a structure that would be able to source or sink 100 mega-amperes from the interstellar environment is likely to be mindboggling.
You keep saying this as if there actually was someone here advocating such nonsensical mass ratios. If 0.02c is the fastest we can make the exhaust, then the speed limit for a rocket is around 0.1c. I think fusion can give us about twice that, but I am not entirely sure. Not what we would hope for, but it will do until such time that your accelerator can be built. Which will be never, most likely.
Eniac
“You keep saying this as if there actually was someone here advocating such nonsensical mass ratios. If 0.02c is the fastest we can make the exhaust, then the speed limit for a rocket is around 0.1c.”
With a nuclear rocket.
With an accelerator, with an effective exhaust velocity of 0,02c, you CAN have a delta v of 0,2c.
If you advocate nuclear rocket for a delta v of 0,2c with current/near-future technology (fission), you are implicitly advocating such nonsensical mass ratios.
And even if we somehow got fusion, the energy expended by the accelerator would remain trivial by comparison to that expended by the nuclear rocket.
“At the throughput of 150 kg/s which you have claimed […]”
This is one of the reasons I said in my previous post:
“You expect the accelerator to have a throughput of 168 tons per 20 minutes”
I was too optimistic in proposing this figure, indeed.
The current figure is 3,5 kg per 20 minutes AKA 91,98 tonnes per year (using RFs with NO improvements in capability over the ones we have today)*.
“The trick is NOT to bump the atoms by more than 0.003 m/s while adding or abstracting an electron. If you do, they will diverge from the beam too much to make their next rendezvous with a station. This is difficult, because the energy required to add or abstract an electron is many orders of magnitude greater than that required to bump the atoms off the beam.”
The atoms will be neutralized immediately after they exit the accelerator – beyond which there are a multitude of stations situated light-minutes/hours away, which will correct their trajectory.
The atoms will be charged again just before encountering the ship, at which point it won’t really matter whether they veer off course.
“And you still have not said HOW you are going to do the charging and discharging.”
The discharging – as a preliminary idea – with electron guns near the accelerator.
The charging – again, preliminary – with a laser, close-range, near the ship.
“At the mass throughput you propose, even a 1 m thick block of lead would instantly evaporate, without providing much charging or discharging.”
The current mass of the accelerated fuel is much smaller – 3,5 kg per 20 minutes; small enough to alleviate such problems.
Large enough to be MUCH more favorable than an atomic rocket (energetically; and even regarding the mass of the accelerator).
“So now we have tightened the transverse velocity requirement even further. No atom can have a transverse velocity of more than 100 m per 1/2 year (time it takes the beam to travel between stations)”
The in-travel focusing issue is proving quite problematic, indeed. It calls for a redesign of the focusing stations (lenses, if you prefer – I always used the term in conjunction with optics; hence my observation upwards).
I will give it some thought and post what I’ll came up with.
*At this accelerated mass, we have the performance I outlined in a previous post:
‘Without increasing the RF’s performance at all, with an accelerator 200000 km total length (an oval with the length of 100000 km*), we can launch ships 100 TONNES heavy (we can launch 91,98 tonnes of fuel per year at 0,1c).
If the RF’s performance can be increased by 1 order of magnitude (doable), with an accelerator 200000 km total length (an oval with the length of 100000 km), we can launch ships 1000 TONNES heavy – or launch ships 100 tonnes heavy with an accelerator 20000 km total length.
[…]’
Eniac
About collimation
About the focusing stations near the accelerator: using changing magnetic/electric fields, with the effects weaker inwards, stronger outwards; the stations themselves arranged light-minutes/hours away from the accelerator. Other lenses will make the fuel atoms paths parallel to each other, also by changing magnetic/electric fields.
About the focusing stations en route:
The main lens will be large – 200-300 km in diameter: composed of very thin concentric wires, modifying the trajectory of fuel atoms by changing electric/magnetic fields, with the effects weaker inwards, stronger outwards. Other lenses (tiny by comparison), arranged light-minutes/hours away, will be responsible for the fine-tuning and for making the paths of the fuel atoms parallel to each other.
Note – each such station will be very large/heavy, and 40 such stations are needed.
A 100 tonnes ship will not be able to carry all 40 of them.
As such, 8-12 ships, each 100 tonnes heavy, will be launched consecutively, each carrying a few of these stations, arranging them on the starway, then going back to Earth (by using the fuel sent to it via the newly opened starway).
Better. Now we are down to 12 orders of magnitude, roughly.
I am not so sure. Let us see, power transmitted by a mass stream is P = 1/2 m/[s] v^2, or about 3*10^12 W at m/[s] = 3 g/s and v = 0.2c, or 3000 GW. I am not sure how many microseconds to evaporate that block of lead, but my guess would be not that many. So, foils are still definitely out.
You appear to be making the curious assumption that existing RF units will be able to pass 10^12 times stronger beams just by putting more of them in sequence. This will require more detailed explanation. One of the things limiting accelerator current is the Coulombic repulsion of particles each other, and it is a tough one. Hardly the piece of cake you make it out to be. If it was easy to increase beam intensity, they would have done it for the LHC, because it increases experimental yield directly.
You should brush up on your optics (it applies, I assure you, despite us not talking about light). For a lens to create truly parallel paths, the beam has to originate from a point source. This may be (according to you, myself I have some doubts) possible with the accelerator, but the atoms coming through the first station are distributed across 100 km, and nothing more can be done to focus them. They will invariably disperse further, unless you are talking about measuring and correcting atoms individually, which is not really an option.
What you will end out with after you take the laws of optics into account is a single, very large lens just in the middle between the accelerator and the ship. Or, maybe, two very large lenses, one on each side. You will have a trade-off between the required beam temperature and the size of the lens(es). I think I have in prior posts demonstrated to you the way to calculate this trade-off, you should do so. I predict the result will not be to your liking.
“So, foils are still definitely out.”
There are alternatives – theoretically quite sound (laser, EM).
“Now we are down to 12 orders of magnitude, roughly.”
This relates strictly to the number of atoms (the kinetic energy imparted by an RF remains the same).
And it’s only 6 orders of magnitude more atoms (1,4*10p6, to be exact), accelerated by a single RF, at one time (each atoms receives 1,4*10p6 less kinetic energy than in the LHC).
The other 6 orders of magnitude worth of atoms (1,25*10p6) are gained by the length of the accelerator.
“One of the things limiting accelerator current is the Coulombic repulsion of particles each other, and it is a tough one. Hardly the piece of cake you make it out to be. If it was easy to increase beam intensity, they would have done it for the LHC, because it increases experimental yield directly.”
With the LHC, they try to focus the atom beams to Angstrom precision in order to make them meet at the intersection points. And used are quadrupole magnets, a solution which can be upscaled.
With the half-circles accelerator, I don’t really need such precision – I only have to keep the atoms in the atom beam pipes (during the accelerating phase).
And solutions for focusing the beam already exist – quadrupole magnets; perhaps the RFs can be electrically charged to contain/help contain the beam, etc.
“[the lens size on the starway] I predict the result will not be to your liking.”
I already don’t like it. Too large.
But there is a solution.
After it exits the 200000 km long (perhaps 20000 km) half-circles accelerator, the beam enters another circular accelerator/compressor – this one will only rotate the atom beam via Lorentz force. Also, it will be short – 5-20 km, depending on the strength of the magnetic fields humanity will be able to generate.
This means:
The atoms spread around the 200000 km long half-circles accelerator will be ‘compressed’ into 10-20 km, becoming a far denser beam.
The atoms with different speeds will describe shorter/longer circles AKA neighboring atoms will have the same speed (the differences being at room temperature).
After they exit this second compressor, the neighboring atoms will be neutralized and pressed together/heated to their melting point.
The result will probably be microscopic particles – far smaller than a gram*.
If particles 1 millionth of a gram are so obtained, the kinetic energy will be so large (relatively speaking) as to make possible the setting up on the starway of lenses of less than 2 km in diameter, every 1/10 light year:
For a temperature of 600k, Boltzmann constant*temperature=1,242e-20 j;
The kinetic energy of a particle of 10p-9 kg that travels in one direction 1000 meters per year is 5,027e-19 j in that direction.
As you see, lenses of two kilometers every 1/10 light year, with ~one order of magnitude to spare.
“For a lens to create truly parallel paths, the beam has to originate from a point source. ”
As it will – the lens will focus the atoms towards a single point beyond it (atoms with a specific kinetic energy will be distributed on a specific ‘circle’ surrounding the center of the ‘lens’).
*If this pressing together can be done in the second accelerator/compressor while the atoms are still electrically charged, it will be done there.
They still all have to go through the RF, since they are in series. In terms of atoms passing through every second, you are still at 12 orders of magnitude.
I should stop making minor points next to major ones. You completely forgot to address Columbic repulsion. Perhaps you could calculate the charge of the ion beam, per meter, and then the off-center force that would be exerted on ions at the periphery. I predict it will be quite large, leading to an immediate violent dispersion of the beam and the apparatus with it.
So, you expect the freshly neutralized particles to condense within a few microseconds? Luckily, we will not have to deal with this particular problem, because the ions will have violently dispersed from Coulombic repulsion long before they can be neutralized, much less condensed.
Much more likely, the result will be a rapidly expanding cloud of plasma including the remains of the accelerator.
I am very curious about what type of lens you would be using to focus what amounts to a stream of fine dust. I don’t think it has been invented, yet. The old “changing electric or magnetic fields” hand wave is insufficient.
Note that there will be residual charge on the dust, which will tend to disperse it in very short order. The charge/mass ratio of dust particles is going to vary, so there is really no way to use electric or magnetic fields to apply predictable force for focusing or anything else.
Avatar: You are also still laboring under the misapprehension that a series of more closely spaced lenses can do a better job at focusing than a single lens (or two). This is not the case. The lens size needed is given by a combination of the beam aperture, the distance, and the desired ratio between target and source intensity. More lenses are not going to be an improvement.
Another one of your misapprehensions is that particles are better because their diffraction is negligible. While the latter is true, it is also true that (for much the same reason) particles are unsuitable for resonant amplification (Laser or Maser). Resonant amplification is what enables the incredible and proverbial sharpness that can be achieved with Lasers. Without it, collimation of any type of beam is bound to be many, many orders of magnitude worse. For interstellar beaming, you need better, not worse, and it ain’t going to happen with atoms or dust. No matter how hard you try.
“They still all have to go through the RF, since they are in series. In terms of atoms passing through every second, you are still at 12 orders of magnitude.”
In terms of atoms passing through an RF at any time, they’re still only 6 orders of magnitude more than in the LHC (that’s the density of atoms in the beam).
At no time will more than these many atoms crowded in a single RF.
The accelerator accelerates the other 6 orders of magnitude of atoms in 20 minutes because he’s 6 orders of magnitude longer than the LHC.
“You completely forgot to address Columbic repulsion.”
Actually, I addressed it:
With the LHC, they resolve the Columbic repulsion – and focus the atom beams to Angstrom precision in order to make them meet at the intersection points.
And used are quadrupole magnets, a solution which can be upscaled.
With the half-circles accelerator, I don’t really need such precision – I only have to keep the atoms in the atom beam pipes (during the accelerating phase) – AKA, negating the Columbic repulsion of what amounts to a minuscule number of atoms.
3,5 km spread across 200000 km or 20000 km amounts to relatively VERY FEW charged atoms (we probably have capacitors creating fields stronger than this today) in the cross-section of the atom beam pipe.
And solutions for focusing the beam already exist – quadrupole magnets; perhaps the RFs can be electrically charged to contain/help contain the beam, etc.
“Perhaps you could calculate the charge of the ion beam, per meter, and then the off-center force that would be exerted on ions at the periphery. I predict it will be quite large”
I suspect this Columbic repulsion will come out quite manageable.
“So, you expect the freshly neutralized particles to condense within a few microseconds?”
About ‘freshly’ neutralized – their compression into dust can happen even hours after they’re neutralized (via a specialized station), if necessary*.
“Much more likely, the result will be a rapidly expanding cloud of plasma including the remains of the accelerator.”
The atoms compression can happen quite a ways off from the accelerator, with neutral atoms, if necessary.
“The old “changing electric or magnetic fields” hand wave is insufficient.
Note that there will be residual charge on the dust, which will tend to disperse it in very short order. The charge/mass ratio of dust particles is going to vary, so there is really no way to use electric or magnetic fields to apply predictable force for focusing or anything else.”
The charge/mass ration will not vary if the atoms were neutralized before being condensed into dust (by reasonably well fine tunned electron guns/etc).
As such, the “changing electric or magnetic fields” for deflecting the grains reasonably uniformly will be adequate.
Apropos the dust beam:
The weight for a dust grain that I’ve given – 1p-9 kg – is on the timid side. The dust grains may be much larger than this.
“You are also still laboring under the misapprehension that a series of more closely spaced lenses can do a better job at focusing than a single lens (or two). This is not the case. The lens size needed is given by a combination of the beam aperture, the distance, and the desired ratio between target and source intensity. More lenses are not going to be an improvement.”
My 40 lenses at smaller distances will do just as good a job as a giant lens.
And they have several advantages – their total surface area will be FAR smaller than the area of one giant lens; redundancy.
“While the latter is true, it is also true that (for much the same reason) particles are unsuitable for resonant amplification (Laser or Maser).”
Fortunately, I don’t need resonant amplification to keep the dust beam sufficiently well focused.
A laser or a maser could never do the same thing over interstellar distances – due to diffraction.
*If lithiun deuteride will be used, the lithium and deuterium will be separately accelerated, charged positively and negatively. They could be neutralized (and made into dust) by bringing them together/heating them in the second accelerator/compressor.
If thorium is accelerated, the 1-neutralisation and 2-compression in a station is necessary.
Apropos “In terms of atoms passing through every second, you are still at 12 orders of magnitude.[beyond the LHC]”
Not really.
Atoms in the LHC are ~10 times faster than atoms in the half-circles accelerator.
But, per meter (cm, km, whatever), there are ~10p6 more atoms in the atom beam of the half-circles accelerator.
So – per second, only 10p5 more atoms will pass through an RF of the half-circles accelerator.
“3,5 km spread across 200000 km or 20000 km amounts to relatively VERY FEW charged atoms (we probably have capacitors creating fields stronger than this today) in the cross-section of the atom beam pipe.”
That should be: 3,5 kg, NOT km.
I think the ones they are about a meter in size. Scaled up by 6 orders of magnitude, they would be quite impressive.
About 10^16 per meter. Not terribly many, but they are all charged. In a hurry, I get roughly 10^15 m/s^2 for the acceleration of a singly charged Uranium atom 1 m away from such a dense beam. I might have made a mistake, though. The field strength there is a whopping 10^9 V/m (http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elecyl.html, lambda ~ 0.001 C/m), yielding a force (qE) of ~ 10^-10 N and an acceleration (F/m) of ~ 10^15 m/s^2.
Doubtful. Anyway, capacitors will not focus a beam, unfortunately, just deflect it. The methods of focusing (quadrupole lenses, mostly) are a lot less powerful. I will give you the 6 orders of magnitude in density, but since Coulombic repulsion goes with the square of the charge density, we would be right back to 12 orders of magnitude in the corrective forces needed. I am afraid that this does not translate into bigger quadrupoles, but rather stronger ones. You are thus talking about increasing the magnetic field strength by 12 orders of magnitude, which is absurd.
I do not think you have demonstrated that.
I do not think so. You will have to come up with a credible design for a dust lens, as such a thing is not known in the art.
If by “reasonably uniformly” you mean accurate to within an angular uncertainty of 10^-13, yes, then it might be adequate.
Still curious about the how, though, since dust grains are mostly unaffected by “changing electric or magnetic fields”, and if they are, it is according to their residual charge, which I wish you good luck in controlling to the required precision. Or, they weakly respond to gradients according to their polarizability, which depends on size and shape, neither of which can be made “reasonably uniform” according to any definition, much less the required one from above.
Eniac
Coulombic repulsion:
If we assume there are 3.5 kg of thorium in a 20000 km long accelerator, then there are 0,000175 g or 4.4112069*10^17 atoms in a meter of the accelerator.
Let us say the thorium atoms have no electrons – hypothetically, of course, and very unfavorable. Also, let us assume they form a point charge, instead of being spread over a meter – also very unfavorable.
The number of protons per meter of accelerator would be 3.97008621*10^19.
The total charge of these protons is q=6.36007811 coulomb.
How to contain this force?
The RFs must contain a charged subcomponent that contains at least 3.97008621*10^19 more protons than it contains electrons, is MUCH heavier than 0,000175 grams (the grams of thorium atoms in a meter of the accelerator), and can withstand the repulsion force.
A force of 6.36007811*10^9 N can be withstood with few problems by materials with a tensile strength of 1000 MPa or above.
Just because charged components are not used to focus atom beams does not mean they cannot be used.
The lenses on the starway:
The dust beam will be composed of packets that have the same forward velocity (the atoms that made the dust being previously sorted by Lorentz force, neutralized and compressed).
The dust beam will encounter the IMF. The interaction will raise its temperature to 600K*.
As I said, for a temperature of 600k, Boltzmann constant*temperature=1,242e-20 j;
The kinetic energy of a particle of 10p-9 kg that travels in one direction 1000 meters per year is 5,027e-19 j in that direction – with one order of magnitude to spare.
For this kinetic energy, the sideways speed of the dust will be, at most, 3.1709792*10^-5 m/s.
The FIRST LENS has 3 layers.
The first 2 layers have, as their purpose, to nullify the sideways speed of the dust (bring it to 0).
How?
The fist layer will be composed of a static magnetic field. The magnetic field lines will form concentric circles around the center of the lens. The magnetic field will get stronger as one gets from the center of the lens to its edge.
The dust that has no sideways speed is not affected by the lens – it will experience no change in the magnetic flux**.
The dust with sideways speed outwards will be given an electromotive force by the lens until this sideways speed will be nullified***.
The dust sideways speed inwards will be given an electromotive force by the lens, increasing this sideways speed.
The second layer will be composed of a static magnetic field. The magnetic field lines will form concentric circles around the center of the lens. The magnetic field will get stronger as one gets from the edge of the lens to its center.
The dust that has no sideways speed is not affected by the lens – it will experience no change in the magnetic flux.
The dust with sideways speed inwards will be given an electromotive force by the lens until this sideways speed will be nullified.
The third layer of the lens will use a changing magnetic field (varying according to the position on the lens) to deflect by electromotive force the now parallel-moving dust grains towards a focal point.
The SECOND LENS will be much smaller than the first, will be situated at the focal point and will make the paths of the dust grains again parallel.
*Due to the extremely low density of ISM, the dust grains charged by it will be very few; as such, they are acceptable losses.
**When they enter the magnetic field of the lens, the dust grains will experience an electromotive force affecting their forward speed; due to the weak intensity of the magnetic field and the high 0.1c speed of the particles, this effect will be negligible.
***For a speed of, at most, 3.1709792*10^-5 m/s, the electromotive force can be very weak and still fulfill its purpose, the static magnetic field will be very weak.
Yes, but what about the field strength? I calculated 10^9 V/m, 1 meter away from the beam, but with your numbers, it would be more than 10^12 V/m. These are enormous fields.
You forget that the lens cannot apply just the right force to any given atom, it has to apply the same force to all the atoms in the same place. If those have different sideways velocities, they will continue to do so, and it will vary by MUCH more than 3*1-^-5 m/s. You might want to read up on “conservation of radiance”. What you are proposing is equivalent to sending the light of a light bulb through a cleverly designed set of lenses, thereby turning it into a laser beam. Nice fantasy, but not going to happen.
I am not so sure about that. In fact, the ISM between here and Alpha Centauri amounts to a condensed layer a few microns thick. Any dust grain smaller than a micron will be completely annihilated by it, not just charged a little bit. Larger grains might survive, but not uncharged….
Also, you have not really explained how a magnetic field will change the course of a neutral dust grain. At all, and much less to the degree of precision necessary. Are those dust grains paramagnetic, diamagnetic, or what? All with the exact same amount of magnetisability, or is some variation due to shape and size allowed? If so, how much variation? Are you sure that you can avoid having even a single extra charge on them, which would make them deviate due to Lorentz force? How would you accomplish that, during the fairly violent processes of neutralization and compaction?
“Also, you have not really explained how a magnetic field will change the course of a neutral dust grain.”
By electromotive force – it also affects particles not electrically charged (as per Faraday’s law of induction).
For example, particles inside a mass drives don’t have to be charged to be accelerated by the emf.
“You forget that the lens cannot apply just the right force to any given atom, it has to apply the same force to all the atoms in the same place.”
But it can.
The very speed and trajectory of any given particle will calibrate the received electromotive force (it will ‘decide’ the magnetic flux change experienced by the particle). The magnetic fields that do this will be static themselves (I explained in more detail above).
“I am not so sure about that. In fact, the ISM between here and Alpha Centauri amounts to a condensed layer a few microns thick. Any dust grain smaller than a micron will be completely annihilated by it, not just charged a little bit.”
I’m sending 1000 tonnes worth of dust grains.
A few microns thick worth of ISM will not even affect 1 kg worth of dust grains.
“Are you sure that you can avoid having even a single extra charge on them, which would make them deviate due to Lorentz force?”
As said – the dust grains that gained electric charge via ISM are acceptable losses.
Apropos this – the dust grain I took as having 1*10^-9 kg; they could very well be 1*10-6 kg – with a corresponding decrease in sideways speed.
I took all the dust grain as having 600K due to interaction with the ISM – when in actuality only the first few pockets of dust grain will have this temperature; the rest will have a FAR lower temperature AKA FAR lower sideways speed.
And even with such very unfavorable assumptions, the lenses would only have to be ~400-500 m in diameter to contain all the dust grains; I took them to be ~2000 m in diameter.
“Yes, but what about the field strength? I calculated 10^9 V/m, 1 meter away from the beam, but with your numbers, it would be more than 10^12 V/m.”
I also took the field electric generated by all the charge per meter of accelerator (AKA generated by ALL protons), then I took all protons as if they’re at the periphery of the beam and accelerated by this field (when the vast majority will be in the beam and opposing repulsion forces would cancel out).
I other words, I counted most protons twice.
And even so, with this exaggerately large force:
‘A force of 6.36007811*10^9 N can be withstood with few problems by materials with a tensile strength of 1000 MPa or above.’
Such materials are already known.
And this material can be charged with no problem with the number of protons/electrons necessary – 3.97008621*10^19 protons/electrons.
The Coulombic repulsion problem is solvable today, with current materials.
You are proposing to build a device that generates 10^12 V/m of electric fields.
You are proposing to change the course of dust grains using “electromotive force” with an angular precision of 10^-13.
You are proposing to control the transverse velocity of atoms that have just been violently accelerated to 0.2c to within a very small fraction of a m/s.
You are proposing to collimate a diverging beam to an extent that would make a laser look diffuse, with just lenses.
Each of these things is preposterous by itself, and you have not provided any specifics as to how you would do it. Not surprising, because none of it can be done.
Just a few clarifications:
Thermal motion is not at all relevant for the sideways motion of flying dust grains, you could never ever get it so low that that would matter.
Similarly, material strength does not matter a bit in the creation of strong electric fields. Voltage does, and its tendency to short out (aka “arc”) when it is high enough. This happens at a few MV/m, about 6 orders of magnitude short of our goal, here.
You have not explained how you would assure the predictability (to an accuracy of 10^-13) of the “electromotive force” on dust grains that surely vary in size and shape. And charge, too.
You mean the dust particles will be equipped with navigational systems capable of making decisions? That would indeed work. An actively navigating particle is not subject to the limitations of geometrical optics, including that pesky law of conservation of radiance. This is the approach Kare takes for focusing his sail beam. However, I still see somewhat of a gap in how you propose to equip the particles with said navigational systems during their creation.
You may be overlooking the fact that in most places your beam is spread over square kilometers of area because of the lenses, making it much harder to “punch through” the ISM. You may also be overlooking that fresh ISM will likely drift back into the path of the beam rather quickly, with a “wind speed” similar to that of stars relative to each other, or a few tens of km/s
“Each of these things is preposterous by itself, and you have not provided any specifics as to how you would do it. Not surprising, because none of it can be done.”
Actually, I have.
“Similarly, material strength does not matter a bit in the creation of strong electric fields. Voltage does, and its tendency to short out (aka “arc”) when it is high enough. This happens at a few MV/m, about 6 orders of magnitude short of our goal, here.”
Material strength matters in making sure the charged component will not fly apart. As it turns out, it won’t.
As for the charge – we are in the vacuum of space. There’s nowhere to short out to AKA we can make electric fields orders of magnitude stronger than the ones achievable on Earth.
“You mean the dust particles will be equipped with navigational systems capable of making decisions?”
No need to.
As said, the trajectory and speed of the individual dust grain will determine how much changing magnetic field the dust grain will experience AKA the emf:
The lenses on the starway:
The dust beam will be composed of packets that have the same forward velocity (the atoms that made the dust being previously sorted by Lorentz force, neutralized and compressed).
The dust beam will encounter the IMF. The interaction will raise its temperature to 600K*.
As I said, for a temperature of 600k, Boltzmann constant*temperature=1,242e-20 j;
The kinetic energy of a particle of 10p-9 kg that travels in one direction 1000 meters per year is 5,027e-19 j in that direction – with one order of magnitude to spare.
For this kinetic energy, the sideways speed of the dust will be, at most, 3.1709792*10^-5 m/s.
The FIRST LENS has 3 layers.
The first 2 layers have, as their purpose, to nullify the sideways speed of the dust (bring it to 0).
How?
The fist layer will be composed of a static magnetic field. The magnetic field lines will form concentric circles around the center of the lens. The magnetic field will get stronger as one gets from the center of the lens to its edge.
The dust that has no sideways speed is not affected by the lens – it will experience no change in the magnetic flux**.
The dust with sideways speed outwards will be given an electromotive force by the lens until this sideways speed will be nullified***.
The dust sideways speed inwards will be given an electromotive force by the lens, increasing this sideways speed.
The second layer will be composed of a static magnetic field. The magnetic field lines will form concentric circles around the center of the lens. The magnetic field will get stronger as one gets from the edge of the lens to its center.
The dust that has no sideways speed is not affected by the lens – it will experience no change in the magnetic flux.
The dust with sideways speed inwards will be given an electromotive force by the lens until this sideways speed will be nullified.
The third layer of the lens will use a changing magnetic field (varying according to the position on the lens) to deflect by electromotive force the now parallel-moving dust grains towards a focal point.
The SECOND LENS will be much smaller than the first, will be situated at the focal point and will make the paths of the dust grains again parallel.
*Due to the extremely low density of ISM, the dust grains charged by it will be very few; as such, they are acceptable losses.
**When they enter the magnetic field of the lens, the dust grains will experience an electromotive force affecting their forward speed; due to the weak intensity of the magnetic field and the high 0.1c speed of the particles, this effect will be negligible.
***For a speed of, at most, 3.1709792*10^-5 m/s, the electromotive force can be very weak and still fulfill its purpose, the static magnetic field will be very weak.
“You may be overlooking the fact that in most places your beam is spread over square kilometers of ISM area because of the lenses”
Hardly.
When exiting the accelerator and the nearby lenses , the dust beam should have a diameter of ~10 meters.
A diameter which should be maintained by the lenses en route.
They may not even be necessary, seeing that:
‘The dust grain I took as having 1*10^-9 kg; they could very well be 1*10-6 kg – with a corresponding decrease in sideways speed.
I took all the dust grain as having 600K due to interaction with the ISM – when in actuality only the first few pockets of dust grain will have this temperature; the rest will have a FAR lower temperature AKA FAR lower sideways speed.
And even with such very unfavorable assumptions, the lenses would only have to be ~400-500 m in diameter to contain all the dust grains; I took them to be ~2000 m in diameter.’
And apropos the electric field strength:
‘I also took the field electric generated by all the charge per meter of accelerator (AKA generated by ALL protons), then I took all protons as if they’re at the periphery of the beam and accelerated by this field (when the vast majority will be in the beam and opposing repulsion forces would cancel out).
I other words, I counted most protons twice.’
Actual electric field strength does not exceed 10^9 V/m.
“You may also be overlooking that fresh ISM will likely drift back into the path of the beam rather quickly, with a “wind speed” similar to that of stars relative to each other, or a few tens of km/s”
The ISM encountered by the front of the dust beam AND the ISM that drifts won’t affect more than a few kg forth of fuel.
As said, the ISM is too rarefied to be a serious problem.
PS – Eniac, are you actually reading my posts? Your counterarguments address almost nothing I explained in them. Merely repeating what I’ve already refuted.
For example:
“You are proposing to build a device that generates 10^12 V/m of electric fields.”
Thar would be 10^9 V/m electric fields.
“You are proposing to control the transverse velocity of atoms that have just been violently accelerated to 0.2c to within a very small fraction of a m/s.”
That would be particles 10^-9 to 10^-6 grams particles accelerated to 0,1c.
“You are proposing to change the course of dust grains using “electromotive force” with an angular precision of 10^-13.”
“You are proposing to collimate a diverging beam to an extent that would make a laser look diffuse, with just lenses.”
One – en-route lenses may not even be necessary.
Two – apparently, you didn’t even read my previous post on how I want to focus the dust beam.
This is incorrect. The material that carries the charge will arc all by itself, it does not need gas. It is called field emission.
No, not “until its sideways speed is nullified”. Until it leaves the lens. The angle at which it is emitted depends on many things, including size, shape and magnetizability of the particle. There is no way you can assure for it to be exactly 0. And, oh boy, do you need it to be EXACT to hit the next lens. I believe this invalidates your entire lensing scheme, but maybe you could explain why I am wrong?
I have repeatedly said that you will have many orders of magnitude faster sideways speeds from a multitude of sources other than thermal motion (which for dust grains is not very well defined, anyway). Let us not talk thermal velocities anymore. I regret I brought it up in a different context where it better demonstrated the absurdity of your then current scheme. You have developed a kind of myopic fixation on it, at the expense of all the other reasons why 10^-5 m/s is absurdly low.
And your lenses clearly do not work for reducing the sideways speed, as proved above. And also by the law of conservation of radiance.
There is actually not much room to wiggle, here. Given the charge density in the beam (and I have used a density of 10^16 singly charged atoms per meter), the field at 1 meter distance is given by a simple formula which I have referenced, and I have obtained 10^9 V/m. You have then upped the density by one or two orders of magnitude and made the ions fully charged, which adds at least another 3 orders of magnitude.
There is no double counting that I see in this calculation. You need to worry about double counting when you go on to calculate the Coulombic potential energy stored in the beam. I suspect that, once you calculate that, even without double counting, we are back to the rapidly expanding cloud of plasma as the only viable solution.
As to reading your posts, I do read them all, but there is so much meat (in terms of egregious violations of physical common sense) in them that for lack of time I have to pick the most egregious and easiest to understand. Apparently it is not working.
“No, not “until its sideways speed is nullified”. Until it leaves the lens.”
Not quite. Until the change in magnetic flux experienced equals 0.
When the dust grain flies parallel to the magnetic field lines, the change in magnetic flux (of a static magnetic field, of uniform strength at that radius of the lens) it experiences is 0.
The sideways slower dust grins will fly parallel to the magnetic field lines sooner than the sideways faster dust grains.
In any case, the sideways speed of the fastest dust grains is so small, that making the lens a few meters thick should suffice. At the end of the lens, all the dust grains will fly parallel to each other.
“at the expense of all the other reasons why 10^-5 m/s is absurdly low.”
Fine.
Do name these other reasons, other factors that give the dust grains a larger sideways speed than ~10^-5 m/s.
‘Interaction’ with the extremely rarefied IMF? It will affect too little a percentage of the fuel to matter.
Interstellar magnetic fields? Their EXTREMELY weak influence can be charted and the trajectory of the fuel plotted accordingly.
“Given the charge density in the beam (and I have used a density of 10^16 singly charged atoms per meter), the field at 1 meter distance is given by a simple formula which I have referenced, and I have obtained 10^9 V/m.”
And if you make the atom beam pipe not 2 m, but 20 meters in diameter you can shave more than two orders of magnitude from this value.
And you can leave the atoms singly charged – if necessary.
You are describing something that sounds much like friction. Unfortunately, the behavior of real particles in real fields is not frictional, they bounce and circle about field lines. They certainly won’t “settle” to within 0.0005 m/s in the few nanoseconds they spend in your lens. With your postulated dissipative processes these are not lenses anymore, they are magical motion stoppers which have not yet been invented. They would be of great use in accelerators, where people go to great lengths to try to cool much weaker beams than the one we are talking about.
Here is a few: The large Coulombic forces in the accelerator, the mysterious mechanism that is used to magically condense the particles (but maybe it is so magical that it does not generate any sideways forces at all?), imperfections in the lenses themselves (10^-13 makes six-sigma look really lame). I could name many more, but won’t for now. You named a few good ones yourself, and your handwaving dismissal of them is not convincing, given the EXTREMELY low velocities we are talking about.
A bigger beam would help with Coulombic repulsion, but will wreak havoc with the magnets and other accelerator devices. Magnets get weaker the larger they are, and I think the same goes for RF resonators. You’d be up for a major redesign of everything, and you would gain only a single order of magnitude in reduced field strength. I don’t know how thick the beams in actual accelerators are, but I suspect any experimental particle physicist would laugh in your face if you proposed a 20 m thick beam to her.
“You are describing something that sounds much like friction. Unfortunately, the behavior of real particles in real fields is not frictional, they bounce and circle about field lines. They certainly won’t “settle” to within 0.0005 m/s in the few nanoseconds they spend in your lens.”
It may ‘sound’ like friction, but it’s NOT: it’s unidirectional and amenable to FAR more control than mere friction.
?
Charged particles/dust grains circle around field lines.
As for neutral ones – not really. The lenses are based on how neutral particles interact with magnetic fields by emf – physical laws overwhelmingly proven by experiment.
And yes, the dust grains will spend little time in the lenses, but their sideways velocity will also be extremely small – small enough to be rectified. And the lenses can easily be made FAR thicker than 1 meter (considering that their radius is in the range of mere hundreds of meters).
“the mysterious mechanism that is used to magically condense the particles (but maybe it is so magical that it does not generate any sideways forces at all?), imperfections in the lenses themselves (10^-13 makes six-sigma look really lame).”
‘mysterious mechanism’?
A smaller accelerator that uses Lorentz force to ‘separate’ the atoms according to their speed (the atoms of different speeds forming concentric circles).
The atoms (of similar speed) are then neutralized, heated and pressed together (by emf, etc) to form small particles.
Afterwards, lenses much like the ones I described, located near the accelerators, are used to negate any sideways velocity the particles acquired.
‘imperfections in the lenses themselves’?
Of course, the lenses must be fine tuned. This is not a question of ~’it’s possible’, but of refinement.
I said upwards – fine tunning is a must; much like similar fine tunning is a must for a nuclear rocket, in order for it not to blow up in your face.
“You named a few good ones yourself, and your handwaving dismissal of them is not convincing, given the EXTREMELY low velocities we are talking about.”
About ISM (which affects so few dust grains) and the interstellar magnetic field (which is weak, predictable, and has practically no influence on the dust grains):
You’ll have to detail under what aspect are these unconvincing. These are relatively small, solvable problems.
“A bigger beam would help with Coulombic repulsion, but will wreak havoc with the magnets and other accelerator devices. Magnets get weaker the larger they are, and I think the same goes for RF resonators.”
There is a misunderstanding:
For an atom beam pipe of with a diameter of 2 m, the electric field is 10^9 V/m.
This field is containable in vacuum by an electrostatic field of similar charge. No need to increase the beam pipe diameter.
If you want to go to beyond 10^9 V/m, THEN it’s necessary to increase the beam pipe diameter to 20 m.
As for the RF, they are essentially antennas (powerful ones). You’ll have to explain why EM waves should have trouble with a distance of a mere 20 m.
My lenses “would be of great use in accelerators, where people go to great lengths to try to cool much weaker beams than the one we are talking about.”
As said, the laws my lenses are based on are accurate.
Has anyone thought about using them in modern accelerators (where there is a FAR larger margin for error) and failed? If so, do tell why.
Personally, I doubt anyone tried.
Probably because nobody thought about it?
Or because it works well only with neutral particles, as opposed to the charged ones in accelerators?
In any case, my lenses are ideal for focusing neutral dust grains.
In the posts above, I put one every 1/10 light year – 40 in all to Alpha Centauri.
Due to their small size (thin concentric wires, forming a lens ~hundreds of meters in diameter and ~tens of meters in thickness), a 100 tonnes ship could carry 400 of those, easily enough. Meaning, one lens every 1/100 light year.
Eniac – I recall reading in scientific magazines about interstellar ship proposals – for example, to gather ‘dark matter’ and use it; or to create a singularity (with huge lasers that work ‘just because’) and use it to power the ship.
Franky, my proposal is miles ahead of those scientifically acceptable proposals; unlike those, my proposal doesn’t use any unproven concepts, etc.
My proposal is even miles ahead of a nuclear rocket with a delta v of 0,2c.
To reiterate:
Between a nuclear rocket, solar sails+lasers 9with moon-sized emitters, etc), ramjet, etc and the accelerator, the accelerator is, BY FAR, the better option.
“these are not lenses anymore, they are magical motion stoppers which have not yet been invented.”
Until now. Now, they have been invented.
Congratulations. I suggest you write up a report and send it for peer review in a minor journal in experimental particle physics. You may get some useful suggestions. I won’t say what I think they might be…