First hiatus
When I wrote on 28 August that other things had a way of intervening, one such "thing" had already done so. Now two more have; to the extent that I must now assign a higher priority to resolving these issues than posting to this blog.
I hope to be back by early November, but it may not be until some time in December.
I have quite a bit more to say here, and fully intend to say it. Until then, I guess it's "au revoir", and certainly not "adieu".
Tuesday, 23 September 2014
Wednesday, 17 September 2014
Casimir Effect Space Propulsion Part IV
Could it really work?
As I've said previously, for the last 24 years or so, I have thought that a net Casimir force would probably be exerted on a thin metal plate covered with extremely small tapered holes on one side only. Is this idea "forever impossible", or might it be possible, and just "ahead of its time"?
As always, the only way to be certain about whether any new idea will work is to build a physical prototype, and test it.
Back in 1994, I tried to do exactly that.
Request for Quote
The above image shows a specification drawing that I commissioned in October 1994 (with a few names edited out; otherwise original). I sent it, with a request to quote for any of the foils shown, to a few specialist materials suppliers. I received only one reply, from Goodfellow Cambridge Limited. It's short enough to quote in full:—
Thank you for your enquiry.
We regret that we are unable to manufacture any of the foils shown in your drawing 9410-3-01.
So, twenty years ago no-one could supply the requested foils, or at least no-one was prepared to say to a member of the public that they could supply them. So I was unable to make any further progress with this idea.
Whether these foils could be supplied now (2014) I do not know. My guess is that if they really do act as Casimir force generators, it would be very unlikely now that anyone who could make them would be willing (or even permitted?) to sell them openly.
As I've said previously, for the last 24 years or so, I have thought that a net Casimir force would probably be exerted on a thin metal plate covered with extremely small tapered holes on one side only. Is this idea "forever impossible", or might it be possible, and just "ahead of its time"?
As always, the only way to be certain about whether any new idea will work is to build a physical prototype, and test it.
Back in 1994, I tried to do exactly that.
 |
| Specification drawing for foil with tapered holes. The drawing was originally A3 size, so some notes may not be clear. Alt 1 (on the left) is most relevant for a Casimir Effect force generator. It is for a metal foil 1 micron thick, with hole diameter 0.1 micron at the top surface. |
Request for Quote
The above image shows a specification drawing that I commissioned in October 1994 (with a few names edited out; otherwise original). I sent it, with a request to quote for any of the foils shown, to a few specialist materials suppliers. I received only one reply, from Goodfellow Cambridge Limited. It's short enough to quote in full:—
Thank you for your enquiry.
We regret that we are unable to manufacture any of the foils shown in your drawing 9410-3-01.
So, twenty years ago no-one could supply the requested foils, or at least no-one was prepared to say to a member of the public that they could supply them. So I was unable to make any further progress with this idea.
Whether these foils could be supplied now (2014) I do not know. My guess is that if they really do act as Casimir force generators, it would be very unlikely now that anyone who could make them would be willing (or even permitted?) to sell them openly.
Friday, 12 September 2014
Casimir Effect Space Propulsion Part III
 |
| Fig 3. Data for a 3m³ thruster consisting of many Casimir force generating plates assembled together. Typical configurations for six thrusters in a small spacecraft are also shown. |
A Thruster exploiting Casimir Effect
As described in Fig 2 of my previous post, I expect that a net Casimir force would be exerted on a thin metal plate covered with extremely small tapered holes on one side only. So, to create a thruster of moderate volume that could exert a usefully large force, we would just combine many such plates together, separated by spacers of very low-density, non-conducting material, as shown above. The spacers would permit a reasonable range of zero-point energy fluctuations to exist in the gaps between the plates.
 |
| Fig 4. Spacecraft — horizontal and vertical sections |
As Figs 3 and 4 show, I went as far as doing a schematic design for a small "UFO" - shaped spacecraft incorporating Casimir-force thrusters. (I re-drew Figs 3 and 4 as CAD drawings for this blog, because my original pencil drawings would not scan well).
Sunday, 7 September 2014
Casimir Effect Space Propulsion Part II
My own look at Casimir Effect
Nearly a quarter-century ago, after reading Hal Puthoff's article (Ref 5 below) I decided to look further into the possibility of adapting Casimir Effect into a perpetual force generator for spacecraft propulsion. At that time I wrote the following:—
[quote begins]
Casimir Effect as a possible method of spacecraft propulsion.
1. Casimir — brief biography.
Hendrik B. G. Casimir, one of the foremost theoretical physicists of the 1930's and 1940's, later became Technical Head of the Philips Research Laboratories. He first wrote in 1948 on the effect that now bears his name (Ref 1 & Fig 1). Briefly, this states that if you take two flat parallel metal plates and place them very close together, a force of attraction will occur between them. The origin of the force is of interest — it arises as predicted by quantum theory from fluctuations in the very fabric of space-time itself, which permeate the whole universe.
2. "Reality" of Casimir Effect.
In experiments starting in 1957, Casimir Effect has been verified beyond doubt (Ref 2 p235) yet it is still dealt with poorly, if at all, in physics courses. Also for a long time after Ref 1 was published, even specialists seemed unaware of it. Thus Bryce DeWitt wrote in 1989 (Ref 2 P247):—
"This made me sit up and take notice. I knew nothing of Casimir's original work (1948,1949) and had not heard of Sparnaay's experiments (1957).... I had always been taught that the zero - point energy of a quantized field was unphysical, and Casimir was saying that this view was wrong.... Just how deep the Casimir effect goes has become apparent in the years since 1960. I can think of hardly anything today more pertinent to quantum gravity."
3. Using Casimir Effect to generate a permanent net force.
The "classical" Casimir Effect occurs because conducting plates placed close together exclude certain zero - point fluctuations from the region between the plates. Note the
important difference between this and, for example, the attraction between two magnets. The fluctuations are truly ubiquitous throughout the universe and are external to the plates, whereas the magnets attract because of localised currents (electron movements) within the magnets.
The crucial question now is, can Casimir Effect cause a net force on just a single metal plate? I say yes, if one side of the plate is covered with tapered, blind holes. See Fig 2. (Note the extremely small hole size).
4. Why a net force should be generated.
4.1 Equivalence Principle
The device of Fig 2 is a microscopic analogue of the acoustic or radar energy absorbing surface used in anechoic chambers etc, so possibly the equivalence principle can be cited in its support. (But note that the details of energy absorption are not quite equivalent).
4.2 Analogy with "classical" Casimir Effect.
Provided the sides of the tapered holes are sufficiently smooth, most fluctuations will reflect in a specular rather than a diffuse manner, and the notes on Fig 2 will apply.
4.3 Support from the theoretical literature.
Equation 1.8 of Ref 3 shows that the energy density near a plane conductor deformed by curvature differs from that near a flat one, and the sharper the curvature, the greater the difference. So the device of Fig 2 which has one side flat and the other with many sharp curves should experience different energy densities at the two sides, and hence a net force.
5. Practical details.
See Fig 3.
6. References.
Ref 1. H.B.G. Casimir, 1948, Proc. Kon. Ned. Akad. Wetenschap 51 p793
Ref 2. A. Sarlemijn & M.J. Sparnaay eds 1989 Physics in the Making, Elsevier Science Pub. Co.
Ref 3. P. Candelas, 1982, Annals of Physics (N.Y.) 143, p241
Ref 4. H.B.G. Casimir, 1983 Haphazard Reality: Half a Century of Science, Harper & Row
Ref 5. H. Puthoff, 1990, "Everything for Nothing", New Scientist 28 July 1990 p36
[quote ends]
I'll give Fig 3 mentioned above, and discuss it in detail, next time.
UPDATE, end of 2016:—
I have found two other references predicting that a single plate should experience a strong permanent net Casimir force as I have suggested above, provided one side is left flat, and the other is covered with extremely small indentations. The shape of the indentations is probably less critical than their size. One option suggests a cylindrical shape; and the other trapezoidal, see the Russian (English-language) references http://vixra.org/pdf/1512.0276v1.pdf and http://vixra.org/pdf/1404.0097v1.pdf.
Nearly a quarter-century ago, after reading Hal Puthoff's article (Ref 5 below) I decided to look further into the possibility of adapting Casimir Effect into a perpetual force generator for spacecraft propulsion. At that time I wrote the following:—
[quote begins]
Casimir Effect as a possible method of spacecraft propulsion.
1. Casimir — brief biography.
Hendrik B. G. Casimir, one of the foremost theoretical physicists of the 1930's and 1940's, later became Technical Head of the Philips Research Laboratories. He first wrote in 1948 on the effect that now bears his name (Ref 1 & Fig 1). Briefly, this states that if you take two flat parallel metal plates and place them very close together, a force of attraction will occur between them. The origin of the force is of interest — it arises as predicted by quantum theory from fluctuations in the very fabric of space-time itself, which permeate the whole universe.
 |
| Fig 1. Brief explanation of Casimir Effect, and force calculation for plates separated by 100 nm |
2. "Reality" of Casimir Effect.
In experiments starting in 1957, Casimir Effect has been verified beyond doubt (Ref 2 p235) yet it is still dealt with poorly, if at all, in physics courses. Also for a long time after Ref 1 was published, even specialists seemed unaware of it. Thus Bryce DeWitt wrote in 1989 (Ref 2 P247):—
"This made me sit up and take notice. I knew nothing of Casimir's original work (1948,1949) and had not heard of Sparnaay's experiments (1957).... I had always been taught that the zero - point energy of a quantized field was unphysical, and Casimir was saying that this view was wrong.... Just how deep the Casimir effect goes has become apparent in the years since 1960. I can think of hardly anything today more pertinent to quantum gravity."
3. Using Casimir Effect to generate a permanent net force.
The "classical" Casimir Effect occurs because conducting plates placed close together exclude certain zero - point fluctuations from the region between the plates. Note the
important difference between this and, for example, the attraction between two magnets. The fluctuations are truly ubiquitous throughout the universe and are external to the plates, whereas the magnets attract because of localised currents (electron movements) within the magnets.
The crucial question now is, can Casimir Effect cause a net force on just a single metal plate? I say yes, if one side of the plate is covered with tapered, blind holes. See Fig 2. (Note the extremely small hole size).
 |
| Fig 2. A thin metal plate (shown in cross-section) covered with tapered holes on one side only, as a possible Casimir force generator |
4. Why a net force should be generated.
4.1 Equivalence Principle
The device of Fig 2 is a microscopic analogue of the acoustic or radar energy absorbing surface used in anechoic chambers etc, so possibly the equivalence principle can be cited in its support. (But note that the details of energy absorption are not quite equivalent).
4.2 Analogy with "classical" Casimir Effect.
Provided the sides of the tapered holes are sufficiently smooth, most fluctuations will reflect in a specular rather than a diffuse manner, and the notes on Fig 2 will apply.
4.3 Support from the theoretical literature.
Equation 1.8 of Ref 3 shows that the energy density near a plane conductor deformed by curvature differs from that near a flat one, and the sharper the curvature, the greater the difference. So the device of Fig 2 which has one side flat and the other with many sharp curves should experience different energy densities at the two sides, and hence a net force.
5. Practical details.
See Fig 3.
6. References.
Ref 1. H.B.G. Casimir, 1948, Proc. Kon. Ned. Akad. Wetenschap 51 p793
Ref 2. A. Sarlemijn & M.J. Sparnaay eds 1989 Physics in the Making, Elsevier Science Pub. Co.
Ref 3. P. Candelas, 1982, Annals of Physics (N.Y.) 143, p241
Ref 4. H.B.G. Casimir, 1983 Haphazard Reality: Half a Century of Science, Harper & Row
Ref 5. H. Puthoff, 1990, "Everything for Nothing", New Scientist 28 July 1990 p36
[quote ends]
I'll give Fig 3 mentioned above, and discuss it in detail, next time.
UPDATE, end of 2016:—
I have found two other references predicting that a single plate should experience a strong permanent net Casimir force as I have suggested above, provided one side is left flat, and the other is covered with extremely small indentations. The shape of the indentations is probably less critical than their size. One option suggests a cylindrical shape; and the other trapezoidal, see the Russian (English-language) references http://vixra.org/pdf/1512.0276v1.pdf and http://vixra.org/pdf/1404.0097v1.pdf.
Tuesday, 2 September 2014
Casimir Effect Space Propulsion Part I
Perpetual Force Generator
I may be accused of drifting a bit off-topic with these posts on inertial propulsion etc, but I still have in mind the idea of driving a perpetual motion wheel by means of perpetual force generators arrayed around its rim.
One example of a perpetual force generator would be an inertial propulsion device, for as long as it could be kept running, but there are other possibilities.
The next few posts will examine the concept of a perpetual force generator exploiting Casimir Effect.
The Quantum Vacuum Plasma Thruster
I see that the "Quantum Vacuum Plasma Thruster", an example of (hopefully) practical exploitation of Casimir Effect has appeared on the internet; see the NASA pdf: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110023492.pdf
for more.
Quoting from the above:—
How does a Q-thruster work? A Q-thruster uses the same principles and equations of motion that a conventional plasma thruster would use, namely Magnetohydrodynamics (MHD), to predict propellant behavior. The virtual plasma is exposed to a crossed E and B-field which induces a plasma drift of the entire plasma in the E×B direction which is orthogonal to the applied fields. The difference arises in the fact that a Q-thruster uses quantum vacuum fluctuations as the fuel source eliminating the need to carry propellant. This suggests much higher specific impulses are available for QVPT systems limited only by their power supply's energy storage densities. Historical test results have yielded thrust levels of between 1000-4000 micro-Newtons, specific force performance of 0.1N/kW, and an equivalent specific impulse of ~ 1×10^12 seconds.
While it's good to see NASA actively investigating Casimir force thrusters (at last!) the performance cited seems very poor, when set against the high energy required to produce the electric and magnetic fields.
Can we not do better than this, ideally with a thruster that produces a net Casimir force simply from its own structure/geometry, without the need for any high energy consuming E or B fields? I'll look at that next time.
I may be accused of drifting a bit off-topic with these posts on inertial propulsion etc, but I still have in mind the idea of driving a perpetual motion wheel by means of perpetual force generators arrayed around its rim.
 |
| Wheel with perpetual force generators |
The next few posts will examine the concept of a perpetual force generator exploiting Casimir Effect.
The Quantum Vacuum Plasma Thruster
I see that the "Quantum Vacuum Plasma Thruster", an example of (hopefully) practical exploitation of Casimir Effect has appeared on the internet; see the NASA pdf: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110023492.pdf
for more.
Quoting from the above:—
How does a Q-thruster work? A Q-thruster uses the same principles and equations of motion that a conventional plasma thruster would use, namely Magnetohydrodynamics (MHD), to predict propellant behavior. The virtual plasma is exposed to a crossed E and B-field which induces a plasma drift of the entire plasma in the E×B direction which is orthogonal to the applied fields. The difference arises in the fact that a Q-thruster uses quantum vacuum fluctuations as the fuel source eliminating the need to carry propellant. This suggests much higher specific impulses are available for QVPT systems limited only by their power supply's energy storage densities. Historical test results have yielded thrust levels of between 1000-4000 micro-Newtons, specific force performance of 0.1N/kW, and an equivalent specific impulse of ~ 1×10^12 seconds.
While it's good to see NASA actively investigating Casimir force thrusters (at last!) the performance cited seems very poor, when set against the high energy required to produce the electric and magnetic fields.
Can we not do better than this, ideally with a thruster that produces a net Casimir force simply from its own structure/geometry, without the need for any high energy consuming E or B fields? I'll look at that next time.
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