Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1799121 times)

Offline rfmwguy

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As has been pointed out, getting Q*photon-rocket thrust might be OK so long as it isn't allowed to do work. Well, much work, anyway. We have equations for that, using the stored energy and the power input.
Well, I never promised you a rose garden with constant acceleration for constant power.  This thing has been tested at NASA for periods of what ? about 40 seconds ? and people are already extracting conclusions based on constant acceleration for constant power going to the stars, and forgetting about the 2nd Law ???  ;)

Did forget to put in my test paper that I'll apply power for 5 minutes and longer if gram-force is registered  8)

Offline phaseshift

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Wouldn't the tunnelling effect also be constrained by conservation of momentum and therefore apply at both ends of the frustrum?
You have to look at the energy density regarding radiation pressure, and don't ignore the lateral conical walls.
Then perform a quantum tunneling analysis.  Momentum will be favored to one side if there is a gradient of emission.

correct and
The tunneling effect acts instantaneous. At the moment a photon is tunneling it impulse acts, that's like its reflected in a wall <z (lower qua the real length of the cavity). There has to be a blue shift of the signal means higher frequency like calculated r and z dependent.

Are you sure that's a net blue shift?  The frustum has to gain momentum which means the photon loses energy and red shifts.  Is the blue shift something that photon's do when they tunnel?
"It doesn't have to be a brain storm, a drizzle will often do" - phaseshift

Offline SeeShells

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Wouldn't the tunnelling effect also be constrained by conservation of momentum and therefore apply at both ends of the frustrum?
You have to look at the energy density regarding radiation pressure, and don't ignore the lateral conical walls.
Then perform a quantum tunneling analysis.  Momentum will be favored to one side if there is a gradient of emission.
When I first visited this blog and started to review the tons of papers and wonderful ideas here just to try to get up to speed I ran across this article. It got me to ask (not only for the thermal issues) but the tunneling effect, if anyone had used or considered using extruded metal. I'm not sure but wouldn't the tunneling effect be greater (correct selection of sized holes) with the extruded metal as the deformation of the waveforms impacting the holed areas would be less?
Crazy idea maybe and just thought I'd throw it out there. I'm still planning on using a solid copper construction


Offline sneekmatrix

Wouldn't the tunnelling effect also be constrained by conservation of momentum and therefore apply at both ends of the frustrum?
You have to look at the energy density regarding radiation pressure, and don't ignore the lateral conical walls.
Then perform a quantum tunneling analysis.  Momentum will be favored to one side if there is a gradient of emission.
When I first visited this blog and started to review the tons of papers and wonderful ideas here just to try to get up to speed I ran across this article. It got me to ask (not only for the thermal issues) but the tunneling effect, if anyone had used or considered using extruded metal. I'm not sure but wouldn't the tunneling effect be greater (correct selection of sized holes) with the extruded metal as the deformation of the waveforms impacting the holed areas woconstructiony
Crazy idea maybe and just thought I'd throw it out there. I'm still planning on using a solid copper construction
. Shawyer did mention reflective coating not silver or gold .. Perhaps titanium dioxide? May even help with reducing thermal    problem.

Offline ppnl

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As has been pointed out, getting Q*photon-rocket thrust might be OK so long as it isn't allowed to do work. Well, much work, anyway. We have equations for that, using the stored energy and the power input.
Well, I never promised you a rose garden with constant acceleration for constant power.  This thing has been tested at NASA for periods of what ? about 40 seconds ? and people are already extracting conclusions based on constant acceleration for constant power going to the stars, and forgetting about the 2nd Law ???  ;)

It is interesting that the understanding of the problem has not progressed since I was last here.

If the thing does not give constant thrust but rather thrust that depends on its velocity then you have created a preferred or privileged frame.

Now if you understand that you are creating a privileged frame then you can theorize anything you want. You can even theorize violations of COE or COM as long as you understand that that is what you are doing. If you don't understand the obvious consequences of your own theory then you have little chance of doing anything useful. 

Offline X_RaY

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Wouldn't the tunnelling effect also be constrained by conservation of momentum and therefore apply at both ends of the frustrum?
You have to look at the energy density regarding radiation pressure, and don't ignore the lateral conical walls.
Then perform a quantum tunneling analysis.  Momentum will be favored to one side if there is a gradient of emission.

correct and
The tunneling effect acts instantaneous. At the moment a photon is tunneling it impulse acts, that's like its reflected in a wall <z (lower qua the real length of the cavity). There has to be a blue shift of the signal means higher frequency like calculated r and z dependent.

Are you sure that's a net blue shift?  The frustum has to gain momentum which means the photon loses energy and red shifts.  Is the blue shift something that photon's do when they tunnel?
Yes, if there is a potential barrier (cutoff frequency, diameter )most of the photons would be reflected (may be at the sidewall may be at the energy barrier) but some photons able to tunneling that barrier in just zero time, i think than the cavity acts like shorter than it is.
The small end looks like it is narrow to the small end. Its more a intuitiv thing, i have the luck to work with conical cavities for special applications. Got network analyser, Spectrum Analyzer, circulator, load, tapered cavities all available and i am able to build conical cavities like a want but in K-Band area
 8)
« Last Edit: 06/03/2015 09:34 PM by X_RaY »

Online Rodal

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...It is interesting that the understanding of the problem has not progressed since I was last here....
We have been having fun over here.  Have you had any fun since  you were last here?  ;)
« Last Edit: 06/03/2015 09:55 PM by Rodal »

Offline phaseshift

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Wouldn't the tunnelling effect also be constrained by conservation of momentum and therefore apply at both ends of the frustrum?
You have to look at the energy density regarding radiation pressure, and don't ignore the lateral conical walls.
Then perform a quantum tunneling analysis.  Momentum will be favored to one side if there is a gradient of emission.

correct and
The tunneling effect acts instantaneous. At the moment a photon is tunneling it impulse acts, that's like its reflected in a wall <z (lower qua the real length of the cavity). There has to be a blue shift of the signal means higher frequency like calculated r and z dependent.

Are you sure that's a net blue shift?  The frustum has to gain momentum which means the photon loses energy and red shifts.  Is the blue shift something that photon's do when they tunnel?
Yes, if there is a potential barrier (cutoff frequency, diameter )most of the photons would be reflected (may be at the sidewall may be at the energy barrier) but some photons able to tunneling that barrier in just zero time, i think than the cavity acts like shorter than it is.
The small end looks like it is narrow to the small end. Its more a intuitiv thing, i have the luck to work with conical cavities for special applications. Got network analyser, Spectrum Analyzer, circulator, load, tapered cavities all available and i am able to build conical cavities like a want but in K-Band area
 8)

Just so I know we are saying the same thing - the tunneling itself produces a small blue shift, the transfer of momentum a large red shift - the net is a red shift.  Without a transfer of momentum there would be only the blue shift.

The tunneling is what opens up the closed system to preserve CoM.



"It doesn't have to be a brain storm, a drizzle will often do" - phaseshift

Offline frobnicat

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Apart from the F = P/v (trash Einstein) and F = constant (trash Noether) dynamic models, I did propose a third model which is probably best named "frustrated momentum". In this case, the static F persists until a certain momentum value has been established, equal to an initial impulse given to the system. This momentum having been fully established, F returns to zero Newton.

Shawyer's video seems to fit the "frustrated momentum" bill. McCullough's theory also predicts it IIRC.

Sorry if I may have skipped your model in previous posts. Is it supposed to trash neither ? Can you give a numerical example roughly consistent with current claimed observations (1 or 2 order of magnitude in the ballparks) for a short period (say, about 40s) modest deltaV gain in deep space ?
0/ classical action/reaction thrust(t) ( not sure I get that one, short initial impulse ? )
1/ em drive injected power(t)
2/ mass of spacecraft(t)
3/ acceleration(t) 
from t=0- (initial conditions) to t=40+ (stationary coasting at the new velocity)

Offline PaulF

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Well goup, I'm taking the plunge...right now. At the risk of being ridiculed by my wife, and maybe a couple on these threads ;) , I have attached a Preliminary rev of my proposed emdrive experiment. I welcome any constructive comments, corrections and suggestions. I am putting it out in rough/prelim form to elicit feedback before I get underway in earnest this summer.

In addition, it might motivate others out there to get busy themselves!

p.s. Special thanks to Zellerium for "inspiration" on the experiment outline...

Note: My approach is not to replicate. I've decided on a lower power model for reasons stated in the paper. Nothing written yet has precluded the use of these lower power levels. Perhaps my humble efforts might help with that aspect.

Dave
Good luck with that! As regards the effect of heated air, you'll find (either by calculation or experiment) that if the device is able to let any air escape or enter, the change in weight due to lost air far exceeds the change in weight to due to buoyancy in air caused by ballooning.

You can do a lot better than 100 mg rez on your weighing device for quite moderate bucks. I bought my used Mettler H20 for $80 online and it gets 10 ug.

I'd recommend a fully mechanical weighing device, so as to avoid e/m effects on its electronics.

@rfmwguy: The loss of weight due to air escaping due to heating, can be solved by encasing the part of the experiment that has to be weighed, in an airtight container, preferably transparent :) i.e. perspex or plexiglass. Inexpensive and can be cut to size by the vendor on a standard table top saw. Use a good quality adhesive and you have an airtight container. Bonus: non-conducting. Be sure to ventilate between powerons :) plexiglass does deform at relatively low temps, i think from 60 C it will sag under its own weight. So maybe a somewhat stiffer frame is needed.
« Last Edit: 06/03/2015 10:25 PM by PaulF »

Offline wallofwolfstreet

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As has been pointed out, getting Q*photon-rocket thrust might be OK so long as it isn't allowed to do work. Well, much work, anyway. We have equations for that, using the stored energy and the power input.

Would greatly appreciate a link to this discussion, or maybe a quick summary if it isn't too much trouble. 

Offline WarpTech

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{Yeah, we're on the same page alright. I can't answer this right now, I'm working on the same puzzle but with the TM01 mode, because with an axial conductor down the middle, it's easier to calculate. For any mode, you need to solve the equation;
force density = dD/dt X B + D X dB/dt
Surface charge is one way to look at it, another is the magnetic moment. In free space, the "difference" between these 2 cross products is typically a photon rocket. Inside a cavity however, it becomes an "attenuation rocket". I'm not sure of the outcome yet, so I'm working on it....}

Warptech
When you get some free time have a look at papers by Martin Tajmar.

I have not seen anything new in years, but his old stuff was "misguided". I struggled with his math for a while only to conclude he was doing it wrong and making bogus conclusions.

Offline WarpTech

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...

A mass in a gravitational field "falls" yet nothing is coming out of the enclosing control volume either. It falls precisely because the stress energy Tensor in that volume is skewed to one side. This is what is happening inside the frustum, but only over a narrow bandwidth of the EM spectrum.

If I get it right, you are assuming that a gravitational field is induced by the electromagnetic fields within the frustrum, which I concede since EM fields are sources of the Einstein equations. However, back of the envelope calculations (looking for the gravity due to the mass of a huge EM field within a 1 m**3 volume) show that even in the best scenario the expected gravitational thrusts effects are orders of magnitude below what it has been observed (or claimed).  I would like to have a look at a peer-reviewed reference where the amplification mechanism for narrow bandwith of the EM spectrum is duly explained.

You can look in "Gravity" by Misner, Thorne and Wheeler. I don't have it handy to look up the reference exactly, but if I recall correctly, it's in the section where they talk about gravitational red shift. It is shown that the effect of gravity on a wave function is simply to cause a phase shift that shifts the frequency of the light as it propagates "upward" in a gravitational field. The metric tensor is multiplied by the Energy-momentum 4-vector to transform it into the wave in curved space-time.

P^u*P_u = g_uv*P^u*P^v

or

P^u*P_u = g_uv*(w, k)*(w, k)

Where "w" is the angular frequency and "k" is the wave vector.

The ONLY difference is that gravity attenuates all frequencies and wavelengths identically, where the attenuation of the frustum cavity is ONLY affecting a very narrow bandwidth around the cut-off. The physical effect on those frequencies is identical to gravity. It takes an enormous amount of force, ~ G/c^4 to affect "all" the frequencies in the bandwidth of matter, down to quarks inside of protons. To affect only a narrow bandwidth of EM waves, the energy requirement it is far more reasonable.

What we have here is a frequency dependent metric. |g_uv| = 1, "except" in a narrow bandwidth near the cut-off, and there, -g_11/g_00 = 1 + (a/k)^2, where "a" is the attenuation factor and "k" is the wave number.

Is that clear enough now?

Todd
« Last Edit: 06/04/2015 02:25 AM by WarpTech »

Offline deltaMass

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As has been pointed out, getting Q*photon-rocket thrust might be OK so long as it isn't allowed to do work. Well, much work, anyway. We have equations for that, using the stored energy and the power input.
Well, I never promised you a rose garden with constant acceleration for constant power.  This thing has been tested at NASA for periods of what ? about 40 seconds ? and people are already extracting conclusions based on constant acceleration for constant power going to the stars, and forgetting about the 2nd Law ???  ;)
Yup, and yet other people tell you F = P/v because there's a preferred frame :):):)

Offline ppnl

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...It is interesting that the understanding of the problem has not progressed since I was last here....
We have been having fun over here.  Have you had any fun since  you were last here?  ;)

Well yes. In my spare time I play a zombie survival game. Thing is if I do not understand the rule set of the game then the zombies will eat my brains. Something similar will happen if you don't understand the rule set of the fantasy game you are playing. You may not have zombies but you will do the intellectual equivalent of playing chess with yourself... and cheating.

It is even worse if there is something to the emdrive. There is a marvelous invention out there that you will never understand because you refuse to understand the consequences of your own rule set.

Frame invariance was important long before Einstein. Since Einstein it has become exponentially more important. You can try to find some way to discard it or you can keep it and discard something else. You will make little progress while ignoring it and even less while not even understanding it.

Offline deltaMass

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As has been pointed out, getting Q*photon-rocket thrust might be OK so long as it isn't allowed to do work. Well, much work, anyway. We have equations for that, using the stored energy and the power input.

Would greatly appreciate a link to this discussion, or maybe a quick summary if it isn't too much trouble.
It's dead simple. There's a constant input power P and an initial stored energy E. In a time T the maximum energy that can be extracted is (P*T + E), which would deplete E entirely. This corresponds to an effective average power of (P + E/T). If we equate this to Q*P (true until E is depleted) then we get a determination of the max time we can get away with doing this, i.e. T = E / (P*(Q-1))

Online Mulletron

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Yes
Then, if the fellows in Aachen, Germany, have scaled all their cavity dimensions for Baby EM Drive such that

bigdiameterAACHEN = bigdiameterNASA / (frequencyAACHEN/frequencyNASA)

smalldiameterAACHEN =smalldiameterNASA / (frequencyAACHEN/frequencyNASA)

lengthAACHEN = lengthdiameterNASA / (frequencyAACHEN/frequencyNASA)

they don't have to worry about operating at frequencyAACHEN = 24 GHz, since the number of cycles needed for the photons in the cavity to accelerate to c (if they were free to do so), the coupling, would be what your curve shows at around frequencyNASA = 2 GHz, the NASA frequency ?

Photons don't accelerate. No reference required. It is basic. Any theory requiring such condition needs to go.

Eh- it might just be my peanut gallery prowess speaking here but... what happens when photons or other particles are in one medium and cross the boundary to another medium? Fer instance... particles in the water bath of a nuclear pile (they produce blue glowey stuff known as Cherenkov radiation) because they exceed the speed of light for that medium and shed energy. Bear with me...

So now they leave the water for open air or a vacuum. what happens then?  The speed limit is now faster than they are traveling...could they ( here I mean photons not massive particles) accelerate to the new limit?

EDIT:  And what of experiments with "slow light?" That's where photons are slowed down below their natural speed in recent high tech experiments. Does a slow or trapped photon mean a photon that can be accelerated?
http://en.wikipedia.org/wiki/Cherenkov_radiation
Cherenkov radiation, also known as Vavilov-Cherenkov radiation,[a] is electromagnetic radiation emitted when a charged particle (such as an electron) passes through a dielectric medium at a speed greater than the phase velocity of light in that medium.

https://van.physics.illinois.edu/qa/listing.php?id=2026
https://sciencequestionswithchris.wordpress.com/2014/06/26/how-does-a-photon-accelerate-to-light-speed-so-quickly/
http://www.quora.com/Do-photons-of-light-ever-accelerate
http://www.abc.net.au/science/articles/2015/04/08/4192741.htm

Lastly, "slow light" is the reduction in group velocity, not phase velocity, and has nothing to do with accelerating photons. Also note that "slow light" isn't the same thing as light traveling slower in a medium. "Slow light" is a very particular situation. See below:
http://en.wikipedia.org/wiki/Slow_light
http://physicscentral.com/explore/action/light.cfm
Quote
The BEC is usually opaque, but the researchers made the material transparent by exposing it to a specific arrangement of laser beams. The lasers allowed incoming photons to combine with atoms to form a hybrid particle known as a polariton. Because polaritons get mass from the atoms, they move slower than c. In a BEC, many atoms condense to form one large, super atom. The super atoms are very heavy, and so are the polaritons formed with the incoming photons, and as a result they move much slower than c.
Once again, no photons being accelerated or decelerated.

Yes
Then, if the fellows in Aachen, Germany, have scaled all their cavity dimensions for Baby EM Drive such that

bigdiameterAACHEN = bigdiameterNASA / (frequencyAACHEN/frequencyNASA)

smalldiameterAACHEN =smalldiameterNASA / (frequencyAACHEN/frequencyNASA)

lengthAACHEN = lengthdiameterNASA / (frequencyAACHEN/frequencyNASA)

they don't have to worry about operating at frequencyAACHEN = 24 GHz, since the number of cycles needed for the photons in the cavity to accelerate to c (if they were free to do so), the coupling, would be what your curve shows at around frequencyNASA = 2 GHz, the NASA frequency ?

Photons don't accelerate. No reference required. It is basic. Any theory requiring such condition needs to go.

I can't say I am exactly following them but there is this article here, http://www.nature.com/nphys/journal/v9/n12/full/nphys2777.html .  They seem to suggest acceleration of the beam. 

I always thought of photons more of as waves though considering the path followed by them from a double slit experiment has them emanating not from the holes but from between the holes and then they follow curved paths near the holes then straight paths later on.  On the other hand there is quantum physics. 

I also thought light slowed down when entering a gravitational well but one being in that gravitational well still measures speed c from inside due space time distortion but still I think light should slow down in the well with respect to the rest of space.  I am not sure I would call the change in speed acceleration, though maybe it is. 

I noticed their equation f*c/g is unit-less.  Again, I can't say I understand it but I thought maybe it was in context of the article above?

Okay, where to start...how about what addressing what I actually said, notice I said nothing about the speed of light, yet all the rebuttals were talking about the speed of light. I said acceleration, not speed. I'll entertain those other arguments too.

Quote
Photons don't accelerate. No reference required. It is basic. Any theory requiring such condition needs to go.

http://www.creol.ucf.edu/Research/Publications/7155.pdf (The actual diametric drive paper)
Quote
Similarly, in photonic guiding structures, the effective photon mass can be positive or negative depending on the sign of the associated group velocity dispersion3,4
Photons in this situation have an "effective mass." In this context these particles are now known as polaritons. This is analogous to the BEC slow light situation in the paragraph above. They don't come out and say polaritons, but I'll provide proof of "photons with effective mass" are called polaritons. Polaritons (in this context) arise when photons interact with matter.
http://en.wikipedia.org/wiki/Effective_mass_%28solid-state_physics%29
http://en.wikipedia.org/wiki/Photon#Photons_in_matter
http://en.wikipedia.org/wiki/Polariton (nice hint here about Copper(I) oxide)
http://www.materialsviews.com/cuprous-oxide-a-new-super-material/
http://onlinelibrary.wiley.com/doi/10.1002/pssb.201147402/pdf

Maybe it would be a good exercise to stop treating photons as massive particles and referring to or giving them weight* or accelerating* them and start looking at how photons can gain effective mass???
*http://emdrive.wiki/@notsosureofit_Hypothesis

On light speed in a gravitational well:
http://en.wikipedia.org/wiki/Propagation_of_light_in_non-inertial_reference_frames
http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/speed_of_light.html
Quote
light speeds up as it ascends from floor to ceiling, and it slows down as it descends from ceiling to floor; it's not like a ball that slows on the way up and goes faster on the way down.  Light travels faster near the ceiling than near the floor.  But where you are, you always measure it to travel at c; no matter where you place yourself, the mechanism that runs the clock you're using to measure the light's speed will speed up or slow down precisely in step with what the light is doing.  If you're fixed to the ceiling, you measure light that is right next to you to travel at c.  And if you're fixed to the floor, you measure light that is right next to you to travel at c.  But if you are on the floor, you maintain that light travels faster than c near the ceiling.  And if you're on the ceiling, you maintain that light travels slower than c near the floor.


You are correct. Anyone who thinks photons do not accelerate needs to study General Relativity. A gravitational field "Is" an accelerated reference frame and photons in a g field "do" accelerate relative to a distant observer who is not in the g field. It is called the "coordinate speed of light". To someone observing from inside the g field, c appears to be constant on their relative tangent plane, but that is only because gravitational length contraction and time dilation conspire to make it so in that coordinate system. From the respective coordinate system of a distant observer, c/K in a gravitational field slower than c in free space!

This is a fact, if you don't believe it please study GR and the PV Model of GR. The  speed of light is ONLY constant in an inertial reference frame. As soon as you introduce acceleration or gravity, it is not constant.

Thank you.
Todd

Okay, you're conflating the issue by talking about the speed of light. That isn't addressing the issue....the proposition of massless photons experiencing acceleration, which they cannot. What you are saying about the speed of light is true, but where you are going wrong is counting this as acceleration. This does not mean that photons accelerate or decelerate. Light does not get slowed or sped up. Light being affected by gravity is a geometric argument, light follows the null geodesic.
http://home.comcast.net/~peter.m.brown/gr/c_in_gfield.htm
http://www.physlink.com/Education/AskExperts/ae13.cfm
http://en.wikipedia.org/wiki/Geodesics_in_general_relativity

Once again, just because the speed of light appears to be different in or out of a gravity well as viewed by a distant observer, has nothing to do with photons being accelerated/decelerated.

Light entering a gravity well is blueshifted, light exiting a gravity well is red shifted. Light crossing a gravity well is curved. That is what really happens.

Now onto the PV model of GR...
Harold E. Puthoff has a lot of neat ideas (I've read his work too) and his PV model (his alternative approach to general relativity and quantum mechanics) certainly is interesting reading but none of it is accepted by the scientific community. I do find some merit in some of what he says (because the QED vacuum is a dielectric and vacuum polarization is a real thing) but there is no proof that it has anything to do with gravitation.

EmDrive is already on very shaky ground from a theoretical standpoint, and reports of thrust from them are also on shaky ground. Do we really need fringe science on the table right now? We're all screaming, "It ain't a warp drive!" and you're bringing taboo science to the table that isn't accepted by the scientific community, and proclaiming, it is a warp drive.
http://www.earthtech.org/publications/PV_Found_of_Physics.pdf
http://arxiv.org/find/physics/1/au:+Puthoff_H/0/1/0/all/0/1
« Last Edit: 06/04/2015 03:07 AM by Mulletron »
Challenge your preconceptions, or they will challenge you. - Velik

Online Mulletron

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As many have said before the EW drive just can't work without violating CoM.  ...
Who has said that "the EM Drive drive just can't work without violating CoM"? I don't know of any author that has advocated that the EM Drive works by violating Conservation of Momentum.  Every single theory I know of, Shawyer, McCulloch, Yang, White, you name it, postulates that the EM Drive does not violate conservation of momentum (they all have different explanations as to why momentum is conserved).

I think you can find the forum is full of extremely knowledgeable people who have said as such.  Yes, the authors you listed have made claims but in each case have opened their system such that CoM appears to not be violated and that's how they make the 'claim' they are not violating basic physics.

Focusing on the question I asked might be more productive.  How did Yang open her system such that CoM does not appear to be violated?  Or do you really believe that the EM Drive, a closed cavity, is not violating CoM without a mechanism for opening it up and therefore in your opinion this line of questioning can lead no where?
Perhaps we are using different languages to express this.

I use the following definition of an open system:

"A open system is a system that has external interactions. Such interactions can take the form of information, energy, or material transfers into or out of the system boundary, depending on the discipline which defines the concept. An open system is contrasted with the concept of an isolated system which exchanges neither energy, matter, nor information with its environment. An open system is also known as a constant volume system or a flow system."

According to that definition Dr. White's theory is opening the system by involving the Quantum Vacuum, if we take that the Quantum Vacuum was not part of the system being considered.

 I think that neither Shawyer, McCulloch or Yang are "opening the system".    I don't think that discussing a gradient of group velocity, or Unruh radiation, or considering current density J is opening the system. But I guess that it all depends on what one means by an open system.

As to what Prof. Yang is doing, I don't completely understand it, but my take (with a grain of salt) is that she maybe considering the case of a cavity coupled externally with a waveguide or a coaxial. Thus, the excitations of a mode in a cavity can be modeled by an equivalent electric ( J ) or magnetic (  Jm ) density current representing the sources of the modes. The equivalent magnetic sources are, for example, the magnetic field on a coupling slot between the waveguide and the cavity and the magnetic field generated by a loop coupled with a cavity, while the equivalent electric sources are the currents on a small antenna coupled with the cavity.

We are using the same definition of open system :)

I do think Shawyer  attempted to "open" the cavity by invoking Special Relativity (incorrectly). White uses the QV (almost in an extra dimensional way) to open the system. Yang appears to make no attempt at doing so and thus the reason for my question.

Going extra dimensional, 4+1, also opens up the cavity. However, in looking over Randall/Sundrum I realized that their +1 is not on our D-Brane and is rather the bulk itself.  According to string theory this means RF energy can not enter the +1 dimension,yet  in the same breath Randall wonders if Standard Model particles are in the bulk.  Of course there is the possibility of other dimensions outside of their theory.

I am hoping that given Yang's substantially higher thrust that the manner in which the cavity is opened up could be discerned helping theory move forward.

A perfectly reasonable argument for calling it an open system is to acknowledge that vacuum fluctuations of the electromagnetic field are common to both inside and outside the cavity. They are everywhere.
« Last Edit: 06/04/2015 03:25 AM by Mulletron »
Challenge your preconceptions, or they will challenge you. - Velik

Offline Notsosureofit

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"Maybe it would be a good exercise to stop treating photons as massive particles and referring to or giving them weight* or accelerating* them and start looking at how photons can gain effective mass???
*http://emdrive.wiki/@notsosureofit_Hypothesis"

Yes, "gain effective mass" is the correct interpretation.

Offline deltaMass

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Since a photon cannot be accelerated, no matter how powerful the means brought to bear to effect this, we can say that it possesses an equivalent inertia of infinity. You will note that the equivalence principle is in a bit of trouble as a consequence.

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