maybe they just found a way to interact with neutrinos... instead of virtual particles...
Quote from: Rodal on 06/13/2015 04:00 pm(*) Sorry, no, that's not what happens in the attenuation we are discussing. The attenuation we are discussing is geometrical attenuation that does not result in heat losses, but rather change of phase.Hmmm... isn't "attenuation" the opposite of "amplification" , consequently meaning a decrease in amplitude and the elongation of the frequency till in the end, it becomes zero?A change of phase is just linear shift.Although I understand that, when the wave hits the endplate, the effect of both situations means the wave no longer resonates between the plates , because frequency and distance have to match, I do not understand where the phase shift comes from....I can understand that the waves change amplitude and frequency as they're dragged along the frustum side walls, because they loose some of their energy and consequently have to change in frequency/amplitude. At least that's how I understood (maybe wrongly?) Todd's idea.I don't see why a wave would just shift it's phase, but keep amplitude and frequency the same?I'm just trying to visualize what's happening and how a momentum transfer in a frustum could happen...euh.. Do I have the wrong idea about this whole thing then...?ah well, until we got some serious proof it actually works all theories mean nothing. Sad to see we got 2 DIY that have to postpone their builds, due to circumstances. All hopes are now on the EagleWorks setup.. that's, if they're ever allowed to report back to us in the future...
(*) Sorry, no, that's not what happens in the attenuation we are discussing. The attenuation we are discussing is geometrical attenuation that does not result in heat losses, but rather change of phase.
For the truncated spherical cone and indeed any closed surface there is no net force due to radiation pressure:http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.htmlQuotemaybe they just found a way to interact with neutrinos... instead of virtual particles...Neutrinos do not have much mass. It would take a massive (sorry) flux of neutrinos to produce a detectable reaction force.
Quote from: vulture4 on 06/13/2015 08:19 pmFor the truncated spherical cone and indeed any closed surface there is no net force due to radiation pressure:http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/Cavity.htmlQuotemaybe they just found a way to interact with neutrinos... instead of virtual particles...Neutrinos do not have much mass. It would take a massive (sorry) flux of neutrinos to produce a detectable reaction force.Greg Egan also said; "If the cavity contains a standing wave, then the fields will have a harmonic time dependence of the form sin(ωt) or cos(ωt), and over one complete cycle of the mode, a period of 2π/ω, all the fields will return to their origin values. So at each point in the interior of the cavity, we will have:∫cycle (∂Si / ∂t) dt = Si(t0+2π/ω) – Si(t0) = 0So, averaged over a complete cycle in the same way, each component of the net force on the wall will sum to zero."When the sin(wt) or cos(wt) functions are multiplied by an exponential decay factor, their time average is not zero. So when Q is increasing or Q is decreasing, there should be thrust. If Q is steady, there will be no thrust.Todd
Quote from: deltaMass on 06/13/2015 06:08 pmQuote from: Star One on 06/13/2015 02:36 pmSecond test of the baby EM drive and problems with oscillation. I think they are looking for suggestions to resolve this?...More info.https://hackaday.io/project/5596-em-drive/log/19417-torsion-test-no-data-due-to-oscillationsI find this quite bizarre. The motion seems to have little to do with the natural frequency or its friction, and little to do with whether the drive is on or off. It seems instead to be showing a chaotic time series of air circulation flows local to the apparatus.A vacuum chamber is called for!Probably due to the heat from the light fixture creating natural thermal convection currents. The power from this Baby EM Drive is so small that its effect on the environment is overwhelmed by the light fixture. It is common in Germany to use this kind of light (particularly annoying in hotel rooms ). Short of using a vacuum chamber they should explore lighting that produces a minimum of heat.
Quote from: Star One on 06/13/2015 02:36 pmSecond test of the baby EM drive and problems with oscillation. I think they are looking for suggestions to resolve this?...More info.https://hackaday.io/project/5596-em-drive/log/19417-torsion-test-no-data-due-to-oscillationsI find this quite bizarre. The motion seems to have little to do with the natural frequency or its friction, and little to do with whether the drive is on or off. It seems instead to be showing a chaotic time series of air circulation flows local to the apparatus.A vacuum chamber is called for!
Second test of the baby EM drive and problems with oscillation. I think they are looking for suggestions to resolve this?...More info.https://hackaday.io/project/5596-em-drive/log/19417-torsion-test-no-data-due-to-oscillations
Quote from: WarpTech on 06/13/2015 08:42 pmQuote from: vulture4 on 06/13/2015 08:19 pmIf the evanescent waves leak to the outside, that may produce acceleration of the center of mass.This is why I'm somewhat quiet. It seems that evanescent waves might be the key to this thing and I'm digging. It's interesting a evanescent wave is a standing wave, and could be considered a static stress-energy pressure gradient, only if static and not acting like the off tuned harmonics of a frustum. Evanescent waves are found in near-field regions out to 1/3 wavelength of any RF antenna. So what happens when the Frustum T-mode harmonics collapse creating in the small end decaying evanescent waves? http://en.wikipedia.org/wiki/Evanescent_wave Then this crops uphttp://iopscience.iop.org/0295-5075/76/2/189;jsessionid=B5C4696705DCDDFC9F814A979EDDF64E.c3EPL (Europhysics Letters) Volume 76 Number 2A. A. Stahlhofen and G. Nimtz 2006 Europhys. Lett. 76 189 doi:10.1209/epl/i2006-10271-9Former QED-based studies of evanescent modes identified these with virtual photons. Recent experimental studies confirmed the resulting predictions about non-locality, non-observability, violation of the Einstein relation and the existence of a commutator of field operators between two space-like separated points. Relativistic causality thus is violated by the near-field phenomenon evanescent modes while primitive causality is untouched.Back to digging...Shell
Quote from: vulture4 on 06/13/2015 08:19 pmIf the evanescent waves leak to the outside, that may produce acceleration of the center of mass.This is why I'm somewhat quiet. It seems that evanescent waves might be the key to this thing and I'm digging. It's interesting a evanescent wave is a standing wave, and could be considered a static stress-energy pressure gradient, only if static and not acting like the off tuned harmonics of a frustum. Evanescent waves are found in near-field regions out to 1/3 wavelength of any RF antenna. So what happens when the Frustum T-mode harmonics collapse creating in the small end decaying evanescent waves? http://en.wikipedia.org/wiki/Evanescent_wave Then this crops uphttp://iopscience.iop.org/0295-5075/76/2/189;jsessionid=B5C4696705DCDDFC9F814A979EDDF64E.c3EPL (Europhysics Letters) Volume 76 Number 2A. A. Stahlhofen and G. Nimtz 2006 Europhys. Lett. 76 189 doi:10.1209/epl/i2006-10271-9Former QED-based studies of evanescent modes identified these with virtual photons. Recent experimental studies confirmed the resulting predictions about non-locality, non-observability, violation of the Einstein relation and the existence of a commutator of field operators between two space-like separated points. Relativistic causality thus is violated by the near-field phenomenon evanescent modes while primitive causality is untouched.Back to digging...Shell
If the evanescent waves leak to the outside, that may produce acceleration of the center of mass.
The two are not equal, because the wave decays in the time longer time t + dt, before it can transfer its momentum to the other side.
... No virtual particles. No 5 D Branes. No Woodward instant-action from afar hypothesis. No neutrinos. No breaking of CoM. No dark energy. No dark mass. No fifth force.
Quote from: aceshigh on 06/13/2015 07:37 pmQuote from: Rodal on 06/13/2015 12:52 pmBut the issue we are struggling with is that if there is no mass or no energy being emitted outside the device, how can anything done inside it accelerate its center of mass? Doing so would run counter to the law of conservation of momentum, one of our most cherished laws in Physics.I can move a spacecraft by hitting it with tennis balls from the outside. Or by using a magnet on it from the outside. I cannot move the center of mass of a spacecraft by asymmetrically using a magnet on the inside or asymmetrically hitting its internal walls with tennis balls. One needs to either emit mass or energy to the outside to have propulsion.this is where you need Dr White's explanation right? In that case, the virtual particles are everywhere and I guess they move through the device too. Like if it was water and the device a propeller. Somehow it would be interacting with particles that go through the matter of the device?maybe they just found a way to interact with neutrinos... instead of virtual particles...depending of the case, IF the measurements are real, EVEN if this can never be used for a space drive, it would still be very interesting from a pure scientific standpoint depending on what is causing the effect.@aero in his MEEP FDTD computations gets the evanescent waves to emanate to the outside and outperform a photon rocket. No virtual particles. No 5 D Branes. No Woodward instant-action from afar hypothesis. No neutrinos. No breaking of CoM. No dark energy. No dark mass. No fifth force.
Quote from: Rodal on 06/13/2015 12:52 pmBut the issue we are struggling with is that if there is no mass or no energy being emitted outside the device, how can anything done inside it accelerate its center of mass? Doing so would run counter to the law of conservation of momentum, one of our most cherished laws in Physics.I can move a spacecraft by hitting it with tennis balls from the outside. Or by using a magnet on it from the outside. I cannot move the center of mass of a spacecraft by asymmetrically using a magnet on the inside or asymmetrically hitting its internal walls with tennis balls. One needs to either emit mass or energy to the outside to have propulsion.this is where you need Dr White's explanation right? In that case, the virtual particles are everywhere and I guess they move through the device too. Like if it was water and the device a propeller. Somehow it would be interacting with particles that go through the matter of the device?maybe they just found a way to interact with neutrinos... instead of virtual particles...depending of the case, IF the measurements are real, EVEN if this can never be used for a space drive, it would still be very interesting from a pure scientific standpoint depending on what is causing the effect.
But the issue we are struggling with is that if there is no mass or no energy being emitted outside the device, how can anything done inside it accelerate its center of mass? Doing so would run counter to the law of conservation of momentum, one of our most cherished laws in Physics.I can move a spacecraft by hitting it with tennis balls from the outside. Or by using a magnet on it from the outside. I cannot move the center of mass of a spacecraft by asymmetrically using a magnet on the inside or asymmetrically hitting its internal walls with tennis balls. One needs to either emit mass or energy to the outside to have propulsion.
Quote from: aero on 06/13/2015 10:20 pm...Just not nearly enough force. Better than a Photon rocket though, that's true.Well, it is only 2-D at the moment, and we don't fully understand why the force is greater than a photon rocket, so perhaps if we understand it better, we could construct a better model (3-D ?), perhaps with better constitutive properties (imaginary susceptibility? coupling coefficients? nonlinear coefficients?) that would show even greater response.
...Just not nearly enough force. Better than a Photon rocket though, that's true.
It is frustrating that they have not yet disclosed the internal dimensions of the Baby EM Drive, (last time I checked), although people have asked them in their blog. NASA (Paul March) and Iulian Berca promptly disclosed their geometry, etc. Need the internal dimensions to find out what are the nearby natural frequencies and mode shapes, to know what mode shapes are being excited, and their participation.
Quote from: aero on 06/13/2015 10:20 pm...Just not nearly enough force. Better than a Photon rocket though, that's true.Well, it is only 2-D at the moment, and we don't fully understand why the force is greater than a photon rocket, so perhaps if we understand it better, we could construct a better model (3-D ?), perhaps with better constitutive properties (imaginary susceptibility? coupling coefficients? nonlinear coefficients?) that would show even greater response. Then, again, the force may really be less than a photon rocket in the final analysis.
Baby EmDrive dimensions now released.Height 24.37mmdiameter1 29.64mmdiameter2 16.12mmsmall dameter top edge to centre of injector 5.60mm.
... you seem to violate CoM but don't let that be a brick wall just because someone tells you it does ...