Author Topic: EM Drive Developments Thread 1  (Read 762627 times)

Online Rodal

  • Senior Member
  • *****
  • Posts: 5832
  • USA
  • Liked: 5898
  • Likes Given: 5246
Re: EM Drive Developments
« Reply #740 on: 09/18/2014 02:18 PM »
We should have a sidebar discussion about the transient changes in mass suggested by Mr. Woodward's interpretation of Mach and Sciama's theories.  Maybe in it's own thread, IDK.
Are you going to serve Scotch in this sidebar (as a motivator to join it) ?
« Last Edit: 09/18/2014 02:19 PM by Rodal »

Offline GoatGuy

  • Member
  • Posts: 14
  • Loving Space, NASA, physics and dialog!!!
  • Berkeley CA USA
  • Liked: 0
  • Likes Given: 7
Re: EM Drive Developments
« Reply #741 on: 09/18/2014 02:36 PM »
...
6) Fantastic theories contrary to experience are suggested.

 "Conventional experience" has not  shown  A) translational momentum transfer imparted from .. virtual particles from the quantum vacuum, B) transient changes in mass resulting from EM, [M-E, Mach Effect, I think, is what you meant]

Well, I meant that conventional experience has not shown that ElectroMagnetic (EM) fields produce transient changes in mass (as posited by Woodward's interpretation of the Mach Effect), but however we word this you fully understood what I meant, and I agree with what you state in your latest post

Woodward could answer that his effects are not meant to be conventionally experienced, but that's precisely what Langmuir was pointing out as one of the characteristics with which Langmuir identifies what he defines as Pathologic Science. So, if Woodward would answer that  his effects were never meant to be conventionally experienced, it would still meet that particular Langmuir characteristic with a "Yes". 

By the way, Langmuir did not mean that something that meets his definitions of Pathological Science is necessarily bunk, or wrong, Langmuir just says "watch out," that if one is interested in the phenomena, further, more precise experiments need to be conducted by independent peers, before accepting the results.

The part of Woodward's derivations that I have followed, but don't quite agree with is the magnitude of the increase in relativistic and/or potential mass associated with the oscillatory compression state (potential energy) of the dielectrics in his “inch-worm” thruster analysis.  Can't put my finger on it, but all the Δmc² inertial (or gravinertial?) effects seem many orders of magnitude lower than might be realized as net thrust.  Indeed, with the little math that I can throw around, it doesn't look much different than k = 1/c … which of course is exactly the electromagnetic emission case (un-enhanced by cavity Q theories)

GoatGuy

Offline bad_astra

  • Full Member
  • ****
  • Posts: 1782
  • Liked: 195
  • Likes Given: 170
Re: EM Drive Developments
« Reply #742 on: 09/18/2014 02:46 PM »
Again, the forces current devices exhibit is far less than small satellites see from solar pressure, drag, etc. So any effect would be hard to pull out, especially when you factor in the mass required to power it. Add in the complication that those forces are constant and these devices have only been tested for seconds at a time, it's a recipe for wasted money.

Rather than test at ISS or as a cubesat up front, a device could be tested on a stable high altitude balloon platform of the sort JP Aerospace makes. The test device at high altitude (not perfect vacuum of course), measure all outside movements, replicate at sea level. Compensate for variance. It would not be that expensive, certainly less than a 100k cube sat where all the variances could not be taken into account easily. This looks like a job for near-space.
"Contact Light" -Buzz Aldrin

Online Rodal

  • Senior Member
  • *****
  • Posts: 5832
  • USA
  • Liked: 5898
  • Likes Given: 5246
Re: EM Drive Developments
« Reply #743 on: 09/18/2014 02:57 PM »
Again, the forces current devices exhibit is far less than small satellites see from solar pressure, drag, etc. So any effect would be hard to pull out, especially when you factor in the mass required to power it. Add in the complication that those forces are constant and these devices have only been tested for seconds at a time, it's a recipe for wasted money.

Rather than test at ISS or as a cubesat up front, a device could be tested on a stable high altitude balloon platform of the sort JP Aerospace makes. The test device at high altitude (not perfect vacuum of course), measure all outside movements, replicate at sea level. Compensate for variance. It would not be that expensive, certainly less than a 100k cube sat where all the variances could not be taken into account easily. This looks like a job for near-space.

Yes, that would be the logical step (after the Eagleworks results get verified at JPL, Glenn and John Hopkins), and something like that (but instead in a near Zero G aircraft parabola) is how the "propellant-less" Dipole magnetic flight formation  (explained by classical Maxwell equations, no-need-for-exotic physics) was tested before it was tested in the ISS.  See:  http://ssl.mit.edu/files/website/theses/SM-2013-BuckAlexander.pdf

Apparently, the "on-board-propellant-less" Dipole magnetic flight formation concept has made much more rapid progress (from lab to ZeroG to ISS experimentation) than these "on-board-propellant-less" EM drives...

Of course, the Dipole magnetic flight formation concept is such that the motion of the Center of Mass of the whole formation does not get changed by the formation's dipole magnetic forces (actually that is the purpose of operation) and certainly cannot be used to propel you to Enceladus...
« Last Edit: 09/18/2014 03:17 PM by Rodal »

Offline aceshigh

  • Full Member
  • ****
  • Posts: 606
  • Liked: 171
  • Likes Given: 16
Re: EM Drive Developments
« Reply #744 on: 09/18/2014 03:09 PM »
it's somewhat of a catch 21

22.  My work here is never done.

well, considering it's an expression that makes no sense at all in other languages, I never used it before (in my natural language)

Online Rodal

  • Senior Member
  • *****
  • Posts: 5832
  • USA
  • Liked: 5898
  • Likes Given: 5246
Re: EM Drive Developments
« Reply #745 on: 09/18/2014 03:14 PM »
it's somewhat of a catch 21

22.  My work here is never done.

well, considering it's an expression that makes no sense at all in other languages, I never used it before (in my natural language)
Well, consider that Joseph Heller began writing his novel "Catch 22" in 1953, which @JohnFornaro stated to be one of his favorite years... :)

Offline kch

  • Full Member
  • ****
  • Posts: 1731
  • Liked: 466
  • Likes Given: 8317
Re: EM Drive Developments
« Reply #746 on: 09/18/2014 03:26 PM »
it's somewhat of a catch 21

22.  My work here is never done.

Somewhere, Sir Arthur Adding-one is smiling ...  ;)

Offline JohnFornaro

  • Not an expert
  • Senior Member
  • *****
  • Posts: 9162
  • Delta-t is the salient metric.
  • Planet Eaarth
    • Design / Program Associates
  • Liked: 610
  • Likes Given: 314
Re: EM Drive Developments
« Reply #747 on: 09/18/2014 03:32 PM »
Are you going to serve Scotch in this sidebar?

I'm good for a bottle of 10yr Lapfrog... errrr... Laphroaig.

And izzat really true about Heller?  My vin du table is the Mouton Cadet Bordeaux.  Wonder if there's a bottle of the '53 kicking about?

The part of Woodward's derivations that I have followed...

Uhhh... which derivations, there, kemosabe?

Also, I'm working in the privacy of my own office to follow your v=2k argument. 

Just wanted to note that regarding that argument, silence is golden, and we're all getting rich.  Apparently.
Sometimes I just flat out don't get it.

Online Rodal

  • Senior Member
  • *****
  • Posts: 5832
  • USA
  • Liked: 5898
  • Likes Given: 5246
Re: EM Drive Developments
« Reply #748 on: 09/18/2014 03:44 PM »

And izzat really true about Heller?  My vin du table is the Mouton Cadet Bordeaux.  Wonder if there's a bottle of the '53 kicking about?


Certainly, Ke-mo sah-bee, you can verify this here:

http://books.google.com/books?id=HC5nrYIo21IC&pg=PA140&lpg=PA140&dq=1953+heller+started+writing+catch+22&source=bl&ots=tYyYWNkFBB&sig=4SD2BQxdaHU_jPE7StyNrho-zcE&hl=en&sa=X&ei=-fwaVKSHD9HIggTJrYCIDg&ved=0CEAQ6AEwBA#v=onepage&q=1953%20heller%20started%20writing%20catch%2022&f=false

This is confirmed by Heller's own writings, in the Preface to his magnificent work, see
Page 140 of "Catch-22 - Joseph Heller, New Edition,  edited by Harold Bloom, Sterling Professor of Humanities Harold Bloom"

Or have you been reading Woodward instead of Heller ?
« Last Edit: 09/18/2014 03:58 PM by Rodal »

Online Rodal

  • Senior Member
  • *****
  • Posts: 5832
  • USA
  • Liked: 5898
  • Likes Given: 5246
Re: EM Drive Developments
« Reply #749 on: 09/18/2014 05:01 PM »
And since we were discussing Heller, we might as well quote this famous Italian, that could equally apply to the experiments at Eagleworks ("the opponents, who have the laws on their side" means in this case the Physical Laws as presently understood by the Physics community at large):


<<It ought to be remembered that there is nothing more difficult to take in hand, more perilous to conduct, or more uncertain in its success, than to take the lead in the introduction of a new order of things.

Because the innovator has for enemies all those who have done well under the old conditions, and lukewarm defenders in those who may do well under the new.

This coolness arises partly from fear of the opponents, who have the laws on their side, and partly from the incredulity of men, who do not readily believe in new things until they have had a long experience of them.>>

The Prince

Niccolò Machiavelli   :)
« Last Edit: 09/18/2014 05:07 PM by Rodal »

Offline aero

  • Senior Member
  • *****
  • Posts: 2736
  • 92129
  • Liked: 704
  • Likes Given: 235
Re: EM Drive Developments
« Reply #750 on: 09/18/2014 05:12 PM »
I have seen people in blogs (not in this thread) bringing up the dynamic Casimir effect as perhaps being responsible for the EM drive thrust.  One problem with the dynamic Casimir effect is that the moving mirrors responsible for the effect need to move at relativistic speeds.   If the moving mirrors move at a speed that doesn't approach the speed of light, the virtual particle pairs will easily adapt to the mirror’s movement and continue to come in and out of existence without any dynamic Casimir effectThe speed of the mirror needs to match the speed of the photons to experience the dynamic Casimir effect, and since the photons move at relativistic speeds, this means that the mirror needs to move at relativistic speeds.  If the mirrors move at speeds approaching the speed of light, then yes, the virtual photons then become "real" (in the sense that they will interact with the mirrors) and the mirror begins to produce light.  The problem is that it’s impossible to get an ordinary mirror made of solid matter moving at anything approaching relativistic speeds.  The walls of the Shawyer, Cannae and Dr. White Frustum microwave devices are certainly not moving at relativistic speeds.

Do we know that for sure? The walls are certainly not moving any macroscopic distance, and likely not even microscopic distance, but are they perhaps moving a "nanoscopic" (is that a word?) distance in sympathy with the RF driving power?
IIRC the skin thickness of copper is on the order of 100 nm. If the skin compresses and expands in sympathy with the driving force, and say its amplitude peak-to-peak was 100 nm, then what would the maximum velocity of the skin surface be? At 1900 Mhz, it would move through a complete cycle in 5.26 E-10 seconds. Oops, that's only 380 m/s on average, far from relativistic so you are right.
Quote

Wilson et. al.  (arxiv.org/abs/1105.4714) used, instead of a conventional mirror made of solid matter, a transmission line connected to a superconducting quantum interference device (SQUID). The SQUID changes the effective electrical length of the line and this is equivalent to the movement of an electromagnetic mirror.  When modulating the SQUID at GHz rates, the "mirror" moves back and forth. The transmission line is only 100 micrometres long and the mirror moves over a distance of about a nanometre. It achieves speeds approaching 5 per cent of light speed. Then Wilson cooled the medium (to 50mK), so that the photons would travel slower and match the "mirror" speed.  This worked: it was the first experimental confirmation of the dynamic Casimir effect, they spotted microwave photons emerging from the moving mirror, as predicted some time ago to occur.

But I don't see how this can relate to what Shawyer, Cannae and Dr. White did with the Frustum device:  Wilson had to use a superconducting quantum interference device (which Shawyer, Cannae and Dr.White did not), modulated at GHz rates, and the transmission line was only 100 micrometres long, and everything had to be cooled down.   The walls of the EM drives are not moving at relativistic speeds, and they are several inches apart instead of a nanometer apart.  There are no "mirrors" moving at relativistic speeds,  about a nanometre apart.  And the EM drives experiments are not conducted in a medium at very low temperatures (50mK) to slow down the photons to match the "mirror's" speed.

Your points seem quite reasonable to me, so I can rule out dynamic Casimir effect from my list of possible  causes of the measurement.
Retired, working interesting problems

Offline JohnFornaro

  • Not an expert
  • Senior Member
  • *****
  • Posts: 9162
  • Delta-t is the salient metric.
  • Planet Eaarth
    • Design / Program Associates
  • Liked: 610
  • Likes Given: 314
Re: EM Drive Developments
« Reply #751 on: 09/18/2014 05:36 PM »
Ol' Rodal there, friggin' rox!

Quote from: Rodal
And since we were discussing Heller, we might as well quote ... Niccolò Machiavelli

Who, as it turns out, has summarized the "typical" position of OldSpace vs. NewSpace:

"...fear of the opponents, who have the laws on their side..."

The ex-prez of ULA, MR. Gass, was at least forthright in his congressional admission that ULA "doesn't like competition".

But we digress from the matter at hand which is less about entrenched political interests, and far more about entrenched reality, which seems to most observers, to fly in the face of the innovators at hand.

The dimensional data of the testing apparatus has not yet been revealed by those who know.  In addition, the dimensions and cruciality of the Teflon resonator have yet to be addressed.  And to Rodal,  how crucial is the Teflon thingy to your larger argument regarding stray forces?

And of course, as all know, it is Larson's painstaking research which has taught us the meaning of the common useful term "kemosabe".

Oh.  And where's that bottle of wine I requested?  What am I paying you people to do around here?
« Last Edit: 09/18/2014 05:39 PM by JohnFornaro »
Sometimes I just flat out don't get it.

Offline aero

  • Senior Member
  • *****
  • Posts: 2736
  • 92129
  • Liked: 704
  • Likes Given: 235
Re: EM Drive Developments
« Reply #752 on: 09/18/2014 07:26 PM »
 
I've noted several times on this and other forums, I have the feeling that what we're seeing is a version of the Casimir force. At least that would be a local effect. The problem is that there are so many different Casimir force values for different situations.

Over the last few years their has been a surge in the study of Casimir forces and understanding is advancing rapidly. See the final remarks section, here:
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-97332006000700006

Quote
The Casimir effect has become an extremely active area of research from both theoretical and experimental points of view and its importance lies far beyond the context of QED. This is due to its interdisciplinary character, which makes this effect find applications in quantum field theory (bag model, for instance), cavity QED, atomic and molecular physics, mathematical methods in QFT (development of new regularization and renormalization schemes), fixing new constraints in hypothetical forces, nanotechnology (nanomachines operated by Casimir forces), condensed matter physics, gravitation and cosmology, models with compactified extra-dimensions, etc.

All of this research represents a doubled-edged sword. There are so many variations on the force that it is very time consuming to investigate. (Of course not as bad as having to develop the results one's self.) Here are some prominent areas where results exist, more or less.

1) The normal 2 parallel metallic plates F ~= -0.013/a^4 dyn/cm^2, where a is plate separation in micrometers.
2) The dynamic effect from a vibrating plate
3) The force on a body contained within a body
4) The force variation with the shape of the body
5) The force between a metallic plate and a parallel dielectric sheet
6) The effect of a magnetic field on the forces above.
And most likely others including the effect of the containment vessel (vacuum chamber).

Then of course there is the question of just how the imposed RF signal interacts with the various bodies.

Using measurements for the thruster from photos, and if one were to just assume without justification that the RF signal within the thruster behaves as a non-physical second metallic plate close to the base plate then the claimed thrusts agree closely with the 2 parallel plate Casimir force. (Plate separation about 0.917 micrometers, thrust error 0.005%)

I wish I could justify that assumption of the resonating RF energy acting as a virtual plate. The best I can do at the moment is to use the analogy of signal jamming. Suppose the applied RF signal jams the quantum electromagnetic field signal within the cavity. That, it seems to me would leave an unbalanced Casimir force on the plates and give rise to thrust from the device.   

Oh by the way, If I could justify that assumption, it immediately points to a better design with thrust values a lot higher. For example, shortening the length of the cavity to suppress resonates lengthwise and at the small end, leaving only one resonance mode at the large end. This would eliminate the negative Casimir force on the small end and on the sides of the cone leaving the force on the base plate as thrust.

And note how strongly Casimir force increases with smaller values of separation, a. If this were truly the cause of the measured thrust, then electronically moving the RF energy closer to the base plate causes thrust force to increase by four orders of magnitude for each lowering of the separation by one order of magnitude. That would be a payoff worth pursuing.
Retired, working interesting problems

Offline raketa

  • Full Member
  • **
  • Posts: 211
  • Liked: 36
  • Likes Given: 24
Re: EM Drive Developments
« Reply #753 on: 09/18/2014 07:27 PM »
If EMDrive will work. I was thinking how much power will be needed to bring Mars closer to Sun, in some reasonable life span(20-30) Years.  It will be easier to terraform it if it will get more sun. Maybe this is question for new Topic.

Offline RotoSequence

  • Full Member
  • ****
  • Posts: 751
  • Liked: 554
  • Likes Given: 762
Re: EM Drive Developments
« Reply #754 on: 09/18/2014 07:35 PM »
And since we were discussing Heller, we might as well quote this famous Italian, that could equally apply to the experiments at Eagleworks ("the opponents, who have the laws on their side" means in this case the Physical Laws as presently understood by the Physics community at large):


<<It ought to be remembered that there is nothing more difficult to take in hand, more perilous to conduct, or more uncertain in its success, than to take the lead in the introduction of a new order of things.

Because the innovator has for enemies all those who have done well under the old conditions, and lukewarm defenders in those who may do well under the new.

This coolness arises partly from fear of the opponents, who have the laws on their side, and partly from the incredulity of men, who do not readily believe in new things until they have had a long experience of them.>>

The Prince

Niccolò Machiavelli   :)

This entire discussion tangent is patently absurd. Skeptics of EM drives (those who aren't looking to write click-bait stories, at least) aren't looking to preserve the old order for their gain. These sorts of comparisons are laughably bad at best, and dogmatically polarizing at worst. Science is the derivation of facts, not a battle for the hearts of men!

Skeptics are skeptical because they want to be sure it's real, lest they be incredibly disappointed by the promise of another technology that did not do what they hoped, finding themselves needing to make embarrassing retractions, or spending a fortune on something that does nothing. There is not enough evidence to prove that the effects of EM drives are real, and until that evidence is gathered, it is everyone's due diligence to seek out flaws with the theory and the devices themselves.

It's a lot of fun to imagine what might be done with the technology, and I very much want it to be real, but we should all be operating under the assumption that EM drives appear to work because one thing or another about the experiments are wrong.
« Last Edit: 09/18/2014 07:44 PM by RotoSequence »

Offline aero

  • Senior Member
  • *****
  • Posts: 2736
  • 92129
  • Liked: 704
  • Likes Given: 235
Re: EM Drive Developments
« Reply #755 on: 09/18/2014 07:51 PM »
Quote
It's a lot of fun to imagine what might be done with the technology, and I very much want it to be real, but we should all be operating under the assumption that EM drives appear to work because one thing or another about the experiments are wrong.

I agree its a lot of fun, but disagree that we should assume the experiments are wrong. That is simply dismissing the experiments.
Retired, working interesting problems

Online cuddihy

  • Full Member
  • ****
  • Posts: 793
  • Liked: 143
  • Likes Given: 139
Re: EM Drive Developments
« Reply #756 on: 09/18/2014 08:09 PM »

The part of Woodward's derivations that I have followed...

Uhhh... which derivations, there, kemosabe?

Also, I'm working in the privacy of my own office to follow your v=2k argument. 

Just wanted to note that regarding that argument, silence is golden, and we're all getting rich.  Apparently.

Not exactly...Dont want to drag this Eagleworks thread further into a Woodward argument, but Woodward did address the "naive" formulation of how you would see a transient mass effect. He says you need more than a rapidly changing electomagnetic field, you also need bulk acceleration of a discrete mass in that field volume.

Where would you see that set of circumstances outside of man-made?

Online Rodal

  • Senior Member
  • *****
  • Posts: 5832
  • USA
  • Liked: 5898
  • Likes Given: 5246
Re: EM Drive Developments
« Reply #757 on: 09/18/2014 08:39 PM »

 if one were to just assume without justification that the RF signal within the thruster behaves as a non-physical second metallic plate close to the base plate then the claimed thrusts agree closely with the 2 parallel plate Casimir force. (Plate separation about 0.917 micrometers, thrust error 0.005%)

I wish I could justify that assumption of the resonating RF energy acting as a virtual plate. The best I can do at the moment is to use the analogy of signal jamming. Suppose the applied RF signal jams the quantum electromagnetic field signal within the cavity. That, it seems to me would leave an unbalanced Casimir force on the plates and give rise to thrust from the device.   

Oh by the way, If I could justify that assumption, it immediately points to a better design with thrust values a lot higher. For example, shortening the length of the cavity to suppress resonates lengthwise and at the small end, leaving only one resonance mode at the large end. This would eliminate the negative Casimir force on the small end and on the sides of the cone leaving the force on the base plate as thrust.

And note how strongly Casimir force increases with smaller values of separation, a. If this were truly the cause of the measured thrust, then electronically moving the RF energy closer to the base plate causes thrust force to increase by four orders of magnitude for each lowering of the separation by one order of magnitude. That would be a payoff worth pursuing.

<< if one were to just assume without justification that the RF signal within the thruster behaves as a non-physical second metallic plate close to the base plate>>

Precisely, the problem with this line of reasoning, is that according to all our knowledge both from experiments and from Quantum Mechanics, an RF signal cannot behave as a second metallic plate.

Nobel Prize winner Julian Schwinger derived the Casimir effect as the attraction between plates due to a "retarded" van der Waal force: it is essentially due to charges.  There are no van der Waal forces with a RF signal.     Photons have no electric charge.  So whatever is responsible for the measured thrust of the microwave cavities tested at NASA is not what is known (from experiments and from Quantum Mechanics) as the Casimir effect. 

Schwinger's explanation of the Casimir effect is much more powerful than Casimir's explanation.  Schwinger's explanation predicts the correct sign for different geometries.  Casimir's explanation does not.  Furthermore Casimir failed at his attempt to predict the fine structure constant based on his explanation for the Casimir effect.  All our experimental and theoretical knowledge up to now points towards Schwinger's explanation being the better one.

See Jaffe's paper on the Casimir force:  http://cua.mit.edu/8.422/Reading%20Material/Jaffe2005_Casimir.pdf

<<When the plates were idealized as perfect conductors [by Casimir], assumptions were made about the properties of the materials and the strength of the QED coupling , that obscure the fact that the Casimir force originates in the forces between charged particles in the metal plates.>>

This is an excellent lecture, by Peter Milonni (who wrote the book on the Quantum Vacuum:  "The Quantum Vacuum: An Introduction to Quantum Electrodynamics"), on the Casimir effect. 

« Last Edit: 09/18/2014 09:00 PM by Rodal »

Online Rodal

  • Senior Member
  • *****
  • Posts: 5832
  • USA
  • Liked: 5898
  • Likes Given: 5246
Re: EM Drive Developments
« Reply #758 on: 09/18/2014 09:29 PM »
Watch that hockey stick  :)

Offline frobnicat

  • Full Member
  • ****
  • Posts: 518
  • Liked: 500
  • Likes Given: 151
Re: EM Drive Developments
« Reply #759 on: 09/18/2014 09:44 PM »
Rodal could you tell us in a few words if Schwinger's explanation of the Casimir effect as originating from charge effects (more like van der Waals ...) discards the ZPE/vacuum turmoil playing any (direct) role in Casimir forces ? How the two explanations are linked, and how the "vacuum wavelength exclusion" effect serving the Casimir way of explaining the experimental results predicts correct magnitude for flat plates and not other geometries, as seen from this seemingly better framework ?

I should read the paper you linked rather than ask, but my reading queue is still encumbered with Matt Strassler's explanations about virtual particles (you know, 200 or 300 posts ago) and a few dozen other er, interesting things.

BTW if you feel pedagogically inclined and know the answer : from QFT, are the wave propagation speeds c for all the fields, including those that have massive associated particles ?
« Last Edit: 09/18/2014 09:46 PM by frobnicat »

Tags: