...I doubt it will fix it. The "rotation" looks more like simply reflections bouncing side to side, around a circle. 3 antenna will just have 3 overlapping sets of random reflections. We shall see...Todd

Quote from: WarpTech on 08/05/2015 01:51 PM...I doubt it will fix it. The "rotation" looks more like simply reflections bouncing side to side, around a circle. 3 antenna will just have 3 overlapping sets of random reflections. We shall see...ToddHere I present the Poynting vector field for the final 14 time slices. It would be fun if somebody makes this into a movieThe truncated cone Yang/Shell is shown with the small base at the top and the big base at the bottom

I assume that the Casimir effect can take place without the need of using a vacuum using normal ranges of atmospheric pressures.

What mesh grid size are you guys using for those meep sims? It seems like more of a stepped cylinder than a tapered cavity, or is that intended?

I'll be the first to point out that the folks here have probably had quite enough of me discussing CoE and over-unity. But to Bae...I had the same thought. The situation is indeed similar. He is asking us to believe that thrust is proportional to the number of bounces, which is directly related to the Q. So he also has a P*Q factor in his thrust equation. And the obvious question is: how can it be that a cavity which is being pumped steady-state with input power P can yield a force that depends on P*Q? How can that be sustainable for seconds and minutes? It appears that one's extracting more than goes in. I confess to being uncertain about this. I saw his experiment where he got thrust that was indeed 2*P*Q/c. The saving grace might well be that photon mirrors only become efficient as the mirror velocity with respect to the light source approaches c. By this logic, he is only sipping at each beam, and despite the fact that multiple reflections are simultaneously in play (which intensifies the beam of course) he is only taking a small fraction out of each individual beam.But that's an unsatisfactory explanation too, because one could engineer around it. Probably only a mathematical argument could settle it for me.

Quote from: rfcavity on 08/06/2015 03:43 AMWhat mesh grid size are you guys using for those meep sims? It seems like more of a stepped cylinder than a tapered cavity, or is that intended?The lattice is 0.2747255683428571 meters long

Quote from: deltaMass on 08/05/2015 06:59 AMI'll be the first to point out that the folks here have probably had quite enough of me discussing CoE and over-unity. But to Bae...I had the same thought. The situation is indeed similar. He is asking us to believe that thrust is proportional to the number of bounces, which is directly related to the Q. So he also has a P*Q factor in his thrust equation. And the obvious question is: how can it be that a cavity which is being pumped steady-state with input power P can yield a force that depends on P*Q? How can that be sustainable for seconds and minutes? It appears that one's extracting more than goes in. I confess to being uncertain about this. I saw his experiment where he got thrust that was indeed 2*P*Q/c. The saving grace might well be that photon mirrors only become efficient as the mirror velocity with respect to the light source approaches c. By this logic, he is only sipping at each beam, and despite the fact that multiple reflections are simultaneously in play (which intensifies the beam of course) he is only taking a small fraction out of each individual beam.But that's an unsatisfactory explanation too, because one could engineer around it. Probably only a mathematical argument could settle it for me.I haven't seen any documentation on Bae's design, but it sounds like you are talking about a situation where a laser is reflecting between a spacecraft and a mirror presumably located on a more massive object (such as the moon). I have thought about that type of system before, and eventually figured out how it can be consistent with conservation laws. The key is that when a photon reflects off something twice the photon's momentum is transferred, but this only corresponds to a tiny fraction of the photon's energy. This means the photon is barely redshifted and can continue transferring nearly the same momentum each time until: the mirror accelerates enough to cause large redshift, the photon is absorbed by a mirror which converts the energy to heat rather than directed kinetic energy, or the photon misses the reflector.Since I was curious about the conservation of energy for a single reflection at 0 velocity (when normally equations give 0 doppler shift), I worked out the expected doppler shift. This was based off conservation of momentum and energy, keeping around terms that are normally neglected in doppler shift, since the momentum transfer to objects is negligible in most applications.the result is:v2/v1 = sqrt(a^2 + 4*a +1)-a-1, where a=m*c^2/(h*v1)where v2 is the new frequency, v1 is the starting frequency, m is the mass of the mirror that the photon reflects off, h and c are the usual constants.To get an idea of how little energy is transferred in this case, for a photon at 3 GHz, and a mirror mass of only 1e-35 kg, the ratio is 0.999997. Any actual physical mirror with reasonable mass would result in an immeasurably small doppler shift even for much higher frequencies. Repeated reflection just means you get to convert more of the photons energy into the desired form (kinetic energy of your craft) before the rest gets lost in some way.On a more EM drive related note, photon drive amplification from reflections against test chamber walls was one of my first guesses at possible sources of the EM drive thrust.

...The key is that when a photon reflects off something twice the photon's momentum is transferred, but this only corresponds to a tiny fraction of the photon's energy. This means the photon is barely redshifted and can continue transferring nearly the same momentum each time until: the mirror accelerates enough to cause large redshift, the photon is absorbed by a mirror which converts the energy to heat rather than directed kinetic energy, or the photon misses the reflector.Since I was curious about the conservation of energy for a single reflection at 0 velocity (when normally equations give 0 doppler shift), I worked out the expected doppler shift. This was based off conservation of momentum and energy, keeping around terms that are normally neglected in doppler shift, since the momentum transfer to objects is negligible in most applications.the result is:v2/v1 = sqrt(a^2 + 4*a +1)-a-1, where a=m*c^2/(h*v1)where v2 is the new frequency, v1 is the starting frequency, m is the mass of the mirror that the photon reflects off, h and c are the usual constants.To get an idea of how little energy is transferred in this case, for a photon at 3 GHz, and a mirror mass of only 1e-35 kg, the ratio is 0.999997. Any actual physical mirror with reasonable mass would result in an immeasurably small doppler shift even for much higher frequencies. Repeated reflection just means you get to convert more of the photons energy into the desired form (kinetic energy of your craft) before the rest gets lost in some way. bolding addedOn a more EM drive related note, photon drive amplification from reflections against test chamber walls was one of my first guesses at possible sources of the EM drive thrust.

v2/v1 = sqrt(a^2 + 4*a +1)-a-1, where a=m*c^2/(h*v1)where v2 is the new frequency, v1 is the starting frequency, m is the mass of the mirror that the photon reflects off, h and c are the usual constants.

Quote from: aero on 08/06/2015 04:13 AMQuote from: rfcavity on 08/06/2015 03:43 AMWhat mesh grid size are you guys using for those meep sims? It seems like more of a stepped cylinder than a tapered cavity, or is that intended?The lattice is 0.2747255683428571 meters longOh please.

Indeed interesting article. It seems as if the EM drive is now getting a marginally better response in articles like this. Unfortunately it will probably see years of so called wars until a conclusion appears one way or the other.