Thanks for that. But you know what they say extraordinary claims require extraordinary evidence. I'm sure if this is ever proven too a sufficient degree they'll have no problem obtaining funding.
@ MulletronGreat find!Separating the two photon directions allows them to control their interaction (equivalent of the cavity taper and/or dielectric). In the EMdrive the two directions are intimately coupled within the cavity. If you fold figure 1 in half (vertical fold line) you have something like a tapered microwave cavity. I don't see the need to invoke negative mass (they did say effectively) as the same description looks like the "self accelerating" particle papers.The question is "is the nonlinearity a required condition ?".
....Added: If nothing else, it looks like the force (acceleration) is in the right direction (toward the small end).If I'm reading correctly, they did not (?) observe defocusing, and they would still get an effect if the negative mass was zero. (?)
quasiparticles such as electrons and holes in solid-statecrystals, massspring systems or collective excitations such asBoseEinstein condensates in lattices may exhibit a dispersionrelation with regions of inverted curvature where the effective massis negative. Similarly, in photonic guiding structures, the effectivephoton mass can be positive or negative depending on the sign ofthe associated group velocity dispersion
This is directly analogous to a relativistic particle whose mass seems to increase during the courseof acceleration and therefore cannot exceed the velocity of light. Thehyperbolic trajectory of a constantly accelerated relativistic particleviewed from an inertial reference frame coincides well with themotion of our optical diametric drive (dashed white line overlaid toFig. 4a,b; see Supplementary Methods), thus proving the ongoingaction of the propulsion mechanism.
In contrast, when the same Gaussianexcitation excites the lower band (where the effective mass isnegative), the nonlinearity reverses its action and induces strongnonlinear defocusing effects (Fig. 3b).In our set-up, optical diametric drive acceleration is realizedby allowing the self-trapped wave packet of Fig. 3a to nonlinearlyinteract with the defocusing beam shown in Fig. 3b. While thepositive-mass soliton is attracted by the negative-mass beam, thelatter is constantly repelled. As a result, the positive-mass beam willpermanently pursue its negative-mass counterpart while the latterone tries to escape.
Quote from: Star One on 04/14/2015 03:03 pmThanks for that. But you know what they say extraordinary claims require extraordinary evidence. I'm sure if this is ever proven too a sufficient degree they'll have no problem obtaining funding.Sometimes something extraordinary is also pretty subtle. Why can't even modest results that show something new be extraordinary? Perhaps extraordinary is in the intellectual flexibility of the beholder. When does a skeptic's evaluation turn to "that's extraordinary?" And is that a sound benchmark to evaluate the merit?
Quote from: Mulletron on 04/14/2015 02:57 amThe ESA had a study called Ariadna 04/1201 and a contract called PHOTONIMPULS ANR-09-BLAN-0088-01 to investigate Feigel's claims, derive a Lorentz invariant (and correct) description of the Feigel process, and figure out if the QV can be used for propulsion:http://www.esa.int/gsp/ACT/ariadna/projects/ari_study_04-1201.htmlhttp://www.esa.int/gsp/ACT/doc/ARI/ARI%20Study%20Report/ACT-RPT-PHY-ARI-041201-Koln_Feigel.pdfhttp://www.esa.int/gsp/ACT/doc/ARI/ARI%20Study%20Report/ACT-RPT-PHY-ARI-041201-Grenoble_Feigel.pdfAbout the ARIADNA study #04/1201 from the ESA, evaluating the anomalous Feigel Process for the extraction of momentum from a vacuum, I quote the conclusions of the final report (emphasis by me):QuoteOn the basis of our study, we come to the following conclusions: The derivation of the generally covariant relativistic constitutive relations for a moving magnetoelectric medium, together with the subsequent analysis of the vacuum waves travelling through the sample of a finite size shows that the magnetoelectric body will not move, despite the presence of a certain asummetry between the left- and right-moving waves in the matter. However, this only refers to the case of waves due to vacuum fluctuation.For the real waves falling symmetrically from the two sides on a magnetoelectric body, we expect a nontrivial effect of the Feigel type. Thus, we cannot confirm the possibility of "extracting momentum from nothing".So this study pretty much invalidated the anomalous Feigel effect when considering the QFV conjecture, aka "extraction of momentum from the virtual photons of the quantum vacuum fluctuations". It showed however that an anomalous Feigel effect could be obtained with real photons. So for a thruster, does the photons (microwaves ?) generator (magnetron ?) has to be decoupled (exterior) from the thruster or could it be part of it as in an EmDrive?
The ESA had a study called Ariadna 04/1201 and a contract called PHOTONIMPULS ANR-09-BLAN-0088-01 to investigate Feigel's claims, derive a Lorentz invariant (and correct) description of the Feigel process, and figure out if the QV can be used for propulsion:http://www.esa.int/gsp/ACT/ariadna/projects/ari_study_04-1201.htmlhttp://www.esa.int/gsp/ACT/doc/ARI/ARI%20Study%20Report/ACT-RPT-PHY-ARI-041201-Koln_Feigel.pdfhttp://www.esa.int/gsp/ACT/doc/ARI/ARI%20Study%20Report/ACT-RPT-PHY-ARI-041201-Grenoble_Feigel.pdf
On the basis of our study, we come to the following conclusions: The derivation of the generally covariant relativistic constitutive relations for a moving magnetoelectric medium, together with the subsequent analysis of the vacuum waves travelling through the sample of a finite size shows that the magnetoelectric body will not move, despite the presence of a certain asummetry between the left- and right-moving waves in the matter. However, this only refers to the case of waves due to vacuum fluctuation.For the real waves falling symmetrically from the two sides on a magnetoelectric body, we expect a nontrivial effect of the Feigel type. Thus, we cannot confirm the possibility of "extracting momentum from nothing".
A recent publication [Phys. Rev. Lett. 92, 020404 (2004)] raises the possibility of momentum transfer from zero-point quantum fluctuations to matter, controlled by applied electric and magnetic fields. We present a Lorentz-invariant description using field-theoretical regularization techniques. We find no momentum transfer for homogeneous media, but predict a very small transfer for a Casimir-type geometry.
“PT-symmetry breaking alone is not sufficient to have nonreciprocal response; operation in the nonlinear regime is also necessary. In the linear regime, light transmission is always reciprocal regardless of whether PT-symmetry is broken or not,”
Quote from: Rodal on 02/21/2015 01:46 pmQuote from: Notsosureofit on 02/21/2015 01:34 pm....While the formula I've been using is based on satisfying General Relativity, it does not tell us anything about the mechanism of momentum conservation.. PT asymmetry, as Mulletron mentions, is a viable candidate, and nonlinear frequency effects could (in theory) satisfy the requirement.Can anybody present quantitative experimentally-measured data showing significant PT asymmetry or nonlinear frequency effects for a bulk High Density Polyethylene (purchased commercially from McMaster Carr, if my memory serves me correctly ?) used as the dielectric by NASA Eagleworks in their tests ?That could be a Rosetta Stone...
Quote from: Notsosureofit on 02/21/2015 01:34 pm....While the formula I've been using is based on satisfying General Relativity, it does not tell us anything about the mechanism of momentum conservation.. PT asymmetry, as Mulletron mentions, is a viable candidate, and nonlinear frequency effects could (in theory) satisfy the requirement.Can anybody present quantitative experimentally-measured data showing significant PT asymmetry or nonlinear frequency effects for a bulk High Density Polyethylene (purchased commercially from McMaster Carr, if my memory serves me correctly ?) used as the dielectric by NASA Eagleworks in their tests ?That could be a Rosetta Stone...
....While the formula I've been using is based on satisfying General Relativity, it does not tell us anything about the mechanism of momentum conservation.. PT asymmetry, as Mulletron mentions, is a viable candidate, and nonlinear frequency effects could (in theory) satisfy the requirement.
Well the cavity walls may have thin films of nonlinear material on them, but I'm not entirely convinced that nonlinear behavior is absolutely necessary. The asymmetric behavior of the photon timelines may well be the fundamental factor.
A structure can be non-reciprocal when biased with a vector that is odd under time reversal, i.e. the magnetic field, the current, the linear momentum and the angular momentum [J. D. Jackson, Classical Electrodynamics, John Wiley & Sons, Inc., 1999].
The Onsager–Casimir principle states that any odd vector under time reversal, such as electric current and linear momentum, can also produce a non-reciprocal response.
[snip]So from the research above on magnetoelectrics, you need a Casimir geometry:From what I gather, there are 3 potential areas inside the emdrive which can fit into this metric.1) For the unloaded cavity (no dielectric) the gaps where the end plates meet the frustum. Two Casimir plates in a ring, one large, one small.2) For the loaded cavity, the above, but add in the gap between the copper and HDPE as well as the gap between the two HDPE discs.3) More difficult to justify in my opinion, is the whole cavity technically is a Casimir cavity, albeit a gigantic one.So it seems like a good idea to sandwich some Cr2O3 in between the two HDPE discs and/or between the HDPE and the copper end plate. That's why I got a baggie of the stuff to eventually try out. I have some .5 micron in powder form and .3 micron in paste form.
http://www.creol.ucf.edu/Research/Publications/7155.pdf
[snip]Quote from: Mulletron on 04/14/2015 08:58 pm[snip]So from the research above on magnetoelectrics, you need a Casimir geometry:From what I gather, there are 3 potential areas inside the emdrive which can fit into this metric.[snip] 3) More difficult to justify in my opinion, is the whole cavity technically is a Casimir cavity, albeit a gigantic one.Regarding 3): Is it thinkable that the EM-drive is a kind of large 'inverse' Casimir cavity? In the 'normal' Casimir cavity, there is a reduced virtual photon spectrum, compared to outside the cavity. However, one might argue that inside the comparably giant EM-drive cavity, there is an increased real photon spectrum for that specific spatial volume, compared to the outside of the cavity and hence a similar effect arises as would be the case for a 'normal' Casimir cavity. Does that make sense?What do you think?
[snip]So from the research above on magnetoelectrics, you need a Casimir geometry:From what I gather, there are 3 potential areas inside the emdrive which can fit into this metric.[snip] 3) More difficult to justify in my opinion, is the whole cavity technically is a Casimir cavity, albeit a gigantic one.
Quote from: CW on 04/15/2015 05:42 am[snip]Quote from: Mulletron on 04/14/2015 08:58 pm[snip]So from the research above on magnetoelectrics, you need a Casimir geometry:From what I gather, there are 3 potential areas inside the emdrive which can fit into this metric.[snip] 3) More difficult to justify in my opinion, is the whole cavity technically is a Casimir cavity, albeit a gigantic one.Regarding 3): Is it thinkable that the EM-drive is a kind of large 'inverse' Casimir cavity? In the 'normal' Casimir cavity, there is a reduced virtual photon spectrum, compared to outside the cavity. However, one might argue that inside the comparably giant EM-drive cavity, there is an increased real photon spectrum for that specific spatial volume, compared to the outside of the cavity and hence a similar effect arises as would be the case for a 'normal' Casimir cavity. Does that make sense?What do you think?It makes sense but the frustum cavity is so huge compared to a Casimir cavity. The Casimir force doesn't dominate in such a spacious regime.
Something that makes me think that time delay phase modulation EM propulsion is going on inside the cavity, [diametric propulsion if you want to call it that] is I remember the big plate being fairly hot like positive work was going on there and the narrow end of the cavity looked fairly cool in comparison (negative work?). If so then propulsion being toward the side doing negative work [the narrow end].
Quote from: Rodal on 04/11/2015 04:40 pmQuote from: rfmwguy on 04/11/2015 03:30 pmThanks for the welcome. I've been around high power RF for many years and have seen low temp PTFE issues at relatively low temps. Specifically, changes in capacitance, yeilding center frequency drift in tchebychev bandpass filters using PTFE tape and discs. Outgassing in hermetically sealed tubes were noticed. Could be totally unrelated but...maybe not.Agreed, outgassing (due to microwave heating of water vapor previously trapped in the HDPE or PTFE polymer dielectric) would be something to watch out for in a vacuum environment at significantly lower temperatures (near 200 deg F) than pyrolysis (>700 deg F). This Lawrence Livermore Lab report on outgassing of water vapor from HDPE is pertinent:Vacuum Outgassing of High Density PolyethyleneL. N. Dinh*, J. Sze, M. A. Schildbach, S. C. Chinn, R. S. Maxwell, P. Raboin, W. McLean IILawrence Livermore National Laboratory, Livermore, Ca, USAhttps://e-reports-ext.llnl.gov/pdf/364291.pdfIt concludes that outgassing of H2O from HDPE can be significantly reduced by vacuum baking at 368 degres K (203 deg F) for a few hours prior to device assembly.
Quote from: rfmwguy on 04/11/2015 03:30 pmThanks for the welcome. I've been around high power RF for many years and have seen low temp PTFE issues at relatively low temps. Specifically, changes in capacitance, yeilding center frequency drift in tchebychev bandpass filters using PTFE tape and discs. Outgassing in hermetically sealed tubes were noticed. Could be totally unrelated but...maybe not.Agreed, outgassing (due to microwave heating of water vapor previously trapped in the HDPE or PTFE polymer dielectric) would be something to watch out for in a vacuum environment at significantly lower temperatures (near 200 deg F) than pyrolysis (>700 deg F).
Thanks for the welcome. I've been around high power RF for many years and have seen low temp PTFE issues at relatively low temps. Specifically, changes in capacitance, yeilding center frequency drift in tchebychev bandpass filters using PTFE tape and discs. Outgassing in hermetically sealed tubes were noticed. Could be totally unrelated but...maybe not.
Quote from: dustinthewind on 04/15/2015 05:16 pmSomething that makes me think that time delay phase modulation EM propulsion is going on inside the cavity, [diametric propulsion if you want to call it that] is I remember the big plate being fairly hot like positive work was going on there and the narrow end of the cavity looked fairly cool in comparison (negative work?). If so then propulsion being toward the side doing negative work [the narrow end]. The small base of NASA's Eagleworks EM Drive truncated cone is insulated by the (2.13 inches) thick polymer HDPE while the large base of the truncated cone is not insulated and it is directly exposed to induction heating.On the other hand, Prof. Juan Yang in China did not use dielectric inserts, and hence neither end of their truncated cone EM Drive was insulated. The temperature at the center of the small end (thermocouple #1) in the Chinese experiment rose much more than the temperature at the center of the big end (thermocouple #6), actually the small end experienced the highest overall temperature in the Chinese EM Drive experiments.