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#2800 by FattyLumpkin on 28 May, 2016 08:21
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Dr. Rodal, I'm unclear (after the prolonged discussion) as to whether or not a consensus was reached re the calculating of the "Q" for a given cavity. Should one default to the methodology employed by EWL?, and how in fact did they go about their predicting of Q, and calculating the actual Q in their experiments? I'd like to jot these down into the "agreed upon" column if possible. If no consensus, I'll default to their methodology notwithstanding, and place an "*" by it.
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#2801 by dustinthewind on 28 May, 2016 08:34
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I keep thinking back to the photonic laser thruster . I remember hearing elsewhere that any amount of force can be exerted on the mirrors while stationary, if you have enough light bouncing between the mirrors and low enough losses. It is when the mirrors start to accelerate that you get losses and if it is the light exerting that exerts the force then then by energy conservation it will be red-shifted.
I know that the photonic laser thruster is a different system from an EM drive, but if the light inside a cavity is exerting a force on the cavity, "and the cavity accelerates" then inside the cavity should be observed red-shifted light by conservation of energy. This does lead to a traveling wave and indicates energy transference. (combine one wave traveling one direction and another opposite traveling wave, slightly red-shifted=traveling wave.)
So how might an EM drive be like the photonic thruster? I can't say it is, but here is some speculation on how it might be. Suppose that light at the narrow end is heavier similar to entering a gravitational field. Consider the polarized vacuum equations that suggest light entering a gravity field decreases in velocity which I think was V(K)=Vo/K but increases in mass more rapidly as m(K)=mo*K^(3/2) and over all increasing in momentum, if I remember all this correctly, P(K)=P*K^(1/2). So this is supposing the narrow end is similar to a high K region. I am not sure this would parallel to the wavelength becoming longer toward the narrow end. This is just speculation but I think the light striking one side of the cavity would give it more of a kick than the light striking the other side. After a while if the cavity is free to accelerate the photon should begin to lose energy or red-shift but this is in a closed cavity and supposing the light is increasing in momentum at one end. I really don't know why the K value would change at the narrow end though, and if assuming the K value changes at the narrow end just implies gravity is pulling the cavity.
Now how could it exceed the thrust of a photon rocket. Consider a photon that strikes a mirror once provides a kick of momentum and only loses a small amount of energy due to the acceleration of the object (perfectly reflective). Its momentum is now reversed and it lost some energy to the accelerate mirror so it is ever so slightly red-shifted.
Now consider the photonic laser rocket where light is bounced many times and losses energy due to acceleration of the mirror after many bounces. There is still energy conservation and more energy is lost in this fashion.
Now consider a trapped photon inside a cavity that normally wouldn't lose energy but because its momentum changes on one side via the K value imbalance, the cavity is accelerated and so light inside must lose energy. Would the push of the light be as efficient as photonic laser thruster, corresponding to the energy lost? I am not sure the PV concept would actually give such an acceleration by changing the momentum of the light inside, it is just used as an example in a case where for some reason light does exert such a force inside the cavity and I ask myself is it as efficient as a photonic laser thruster.
Not sure any of that hypothesis makes sense, but I would think if the light is doing the work on the cavity and the cavity accelerates that it should possibly be observable that the light is losing energy and changing in frequency inside. -
#2802 by Rodal on 28 May, 2016 13:18
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Dr. Rodal, I'm unclear (after the prolonged discussion) as to whether or not a consensus was reached re the calculating of the "Q" for a given cavity. Should one default to the methodology employed by EWL?, and how in fact did they go about their predicting of Q, and calculating the actual Q in their experiments? I'd like to jot these down into the "agreed upon" column if possible. If no consensus, I'll default to their methodology notwithstanding, and place an "*" by it.
As to how NASA predicted their quality of resonance Q, they did it by using the definition of Q:
and using COMSOL Finite Element analysis to calculate this formula. The energy stored is a function of the mode shape, which is dictated by the cavity's geometry and excitation method, while the dissipated energy is a function of the the cavity's geometry and excitation method as well as the metal's conductivity.
There are no arbitrary parameters in this definition. No "3 db", no "measure from peak to here".
Concerning reaching consensus on how to measure it experimentally, it appears that no consensus was reached.
When people have asked what is Q, the moderator answered providing a formula on how to approximately estimate Q instead of answering with the actual physical meaning of Q: which is the formula above, an inverse measure of damping of oscillations. Appealing to one of several arbitrary ways to approximately estimate the Q that ignore the mode shape and excitation methods in such a calculation, and use arbitrary numbers like "3 db", or measure this from the peak to "here", of course results in lack of consensus. There are several such approximation estimates.
Imagine if somebody would ask what is the meaning of "height of a tree": what do you think the answer should be? the answer should be the length measurement from base to top of the tree, measured along the line of action of gravity. The answer should not be an approximate method on how to estimate the height of the tree. We should keep a clear mental distinction between the process of approximately estimating something and what is the definition of what one is trying to estimate. Particularly when one estimates numbers like Q=244,000 which are outside of what is expected.
One can approximately estimate the height of the tree by using the angle of elevation and the horizontal distance to the top, for example, but that should not be used as the definition of its height, as it confuses a measurement estimate with its true definition and meaning. An even worse "definition" would be comparing with a measureable object nearby the trunk, eg. a pole or a house of which you know or can measure the height and by looking from a distance how many times that objects fits the tree (that would be like using these estimates using arbitrary numbers like "3 db" that ignore the mode shape and the excitation method).
The estimate is just that, an approximate estimate, and it better make physical sense. A Q of 244,000 for the moderator's copper frustum of a cone is much larger than a) the Q that one would calculate based on a perfect geometry and perfect surface using COMSOL or an exact solution (which would give a maximum Q of less than 100,000) and b) much larger than the experimental values of Q's found in the literature for copper cavities. A Q of 244,000 is to be severely questioned: is it a result of a faulty estimation method? Is it a result of faulty approximations?
NASA's comparisons (Brady et.al.'s report) inspire much more confidence as to the agreement between estimate and COMSOL prediction:QuoteIn this test configuration, the VNA system indicated a quality factor of ~7320...The COMSOL analysis for the first TM211 mode had a predicted quality factor of 7961 (TM212)....
The measured quality factor was ~22,000, with a COMSOL prediction of 21,817 (TE012).
from:
Anomalous Thrust Production from an RF Test Device Measured on a Low-Thrust Torsion Pendulum
David A. Brady*, Harold G. White†, Paul March‡, James T. Lawrence§, and Frank J. Davies**
50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference
The moderator recently posted a FEKO calculation for the mode shape, showing the electric field for mode shape TM013. No figure was posted for the calculated quality factor from FEKO. What quality of resonance Q does FEKO predict for a perfect geometry and perfect surface, based on copper's published value of conductivity?
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#2803 by Monomorphic on 28 May, 2016 13:32
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and using COMSOL Finite Element analysis to calculate this formula.
So NASA calculated their Q using a COMSOL simulation? Does this mean their Q calculation is based on the perfect geometry of the frustum mesh? If so, this could mean their measured Q was much lower, as no build is anywhere near perfect. I have no doubt my Q would be in the tens of thousands if I used FEKO to do the same. Would be nice to see their measured VNA traces and do the standard 3dB measurement. -
#2804 by Rodal on 28 May, 2016 13:35
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NASA estimated their Q using the VNA, as well as performed COMSOL FEA calculations to predict the Q, they did both:and using COMSOL Finite Element analysis to calculate this formula.
So NASA calculated their Q using a COMSOL simulation? Does this mean their Q calculation is based on the perfect geometry of the frustum mesh? If so, this could mean their measured Q was much lower, as no build is anywhere near perfect. I have no doubt my Q would be in the tens of thousands if I used FEKO to do the same. Would be nice to see their measured VNA traces and do the standard 3dB measurement.QuoteIn this test configuration, the VNA system indicated a quality factor of ~7320...The COMSOL analysis for the first TM211 mode had a predicted quality factor of 7961 (TM212)....
The measured quality factor was ~22,000, with a COMSOL prediction of 21,817 (TE012).
So for example, for TM212 the COMSOL FEA prediction, based on a perfect geometry and surface finish and copper conductivity value was Q=7961 while the estimated value based on VNA measurement using NASA's Q estimation method was Q=7320 -
#2805 by Rodal on 28 May, 2016 13:38
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What is particularly concerning about the moderator's measurement estimate of Q as being 244,000 for his frustum of a cone, is that he posted a FEKO computer run showing mode shape TM013.
What is FEKO's calculated value of Q for the TM013 mode shape that was posted for the moderator's frustum?
I understand that his estimated measurement of Q is ~244,000 but I don't recall seeing a predicted (FEKO ?) value of Q.
Is the RF feed still being injected at the big end, as in the moderator's previous experiments?
What is the predicted natural frequency by FEKO for the posted mode shape TM013 and the moderator's frustum geometry? -
#2806 by X_RaY on 28 May, 2016 14:05
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Feko seems to use the same -3dB definition, couldn't find a definitive number of Q created by the program.Dr. Rodal, I'm unclear (after the prolonged discussion) as to whether or not a consensus was reached re the calculating of the "Q" for a given cavity. Should one default to the methodology employed by EWL?, and how in fact did they go about their predicting of Q, and calculating the actual Q in their experiments? I'd like to jot these down into the "agreed upon" column if possible. If no consensus, I'll default to their methodology notwithstanding, and place an "*" by it.
As to how NASA predicted their quality of resonance Q, they did it by using the definition of Q:
and using COMSOL Finite Element analysis to calculate this formula. The energy stored is a function of the mode shape, which is dictated by the cavity's geometry and excitation method, while the dissipated energy is a function of the the cavity's geometry and excitation method as well as the metal's conductivity.
There are no arbitrary parameters in this definition. No "3 db", no "measure from peak to here".
Concerning reaching consensus on how to measure it experimentally, it appears that no consensus was reached.
When people have asked what is Q, the moderator answered providing a formula on how to approximately estimate Q instead of answering with the actual physical meaning of Q: which is the formula above, an inverse measure of damping of oscillations. Appealing to one of several arbitrary ways to approximately estimate the Q that ignore the mode shape and excitation methods in such a calculation, and use arbitrary numbers like "3 db", or measure this from the peak to "here", of course results in lack of consensus. There are several such approximation estimates.
Imagine if somebody would ask what is the meaning of "height of a tree": what do you think the answer should be? the answer should the length measurement from base to top of the tree, measured along the line of action of gravity. The answer should not be an approximate method on how to estimate the height of the tree. We should keep a clear mental distinction between the process of approximately estimating something and what is the definition of what one is trying to estimate. Particularly when one estimates numbers like Q=244,000 which are outside of what is expected.
One can approximately estimate the height of the tree by using the angle of elevation and the horizontal distance to the top, for example, but that should not be used as the definition of its height, as it confuses a measurement estimate with its true definition and meaning. An even worse "definition" would be comparing with a measureable object nearby the trunk, eg. a pole or a house of which you know or can measure the height and by looking from a distance how many times that objects fits the tree (that would be like using these estimates using arbitrary numbers like "3 db" that ignore the mode shape and the excitation method).
The estimate is just that, an approximate estimate, and it better make physical sense. A Q of 244,000 for the moderator's copper frustum of a cone is much larger than a) the Q that one would calculate based on a perfect geometry and perfect surface using COMSOL or an exact solution (which would give a maximum Q of less than 100,000) and b) much larger than the experimental values of Q's found in the literature for copper cavities. A Q of 244,000 is to be severely questioned: is it a result of a faulty estimation method? Is it a result of faulty approximations?
NASA's comparisons (Brady et.al.'s report) inspire much more confidence as to the agreement between estimate and COMSOL prediction:QuoteIn this test configuration, the VNA system indicated a quality factor of ~7320...The COMSOL analysis for the first TM211 mode had a predicted quality factor of 7961 (TM212)....
The measured quality factor was ~22,000, with a COMSOL prediction of 21,817 (TE012).
from:
Anomalous Thrust Production from an RF Test Device Measured on a Low-Thrust Torsion Pendulum
David A. Brady*, Harold G. White†, Paul March‡, James T. Lawrence§, and Frank J. Davies**
50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference
The moderator recently posted a FEKO calculation for the mode shape, showing the electric field for mode shape TM013. No figure was posted for the calculated quality factor from FEKO. What quality of resonance Q does FEKO predict for a perfect geometry and perfect surface, based on copper's published value of conductivity?
That's why I used EMPro for these calculations:
http://forum.nasaspaceflight.com/index.php?topic=39214.msg1536095#msg1536095
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#2807 by Rodal on 28 May, 2016 14:09
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...
Feko seems to use the same -3dB definition, couldn't find a definitive number of Q created by the program.
That's why I used EMPro for these calculations:
http://forum.nasaspaceflight.com/index.php?topic=39214.msg1536095#msg1536095
Prof. Robert Collin in his book "Foundations for Microwave Engineering" in page 508,Figure 7.18 compares the Q for different mode shapes, and shows that the Q for mode shape TE011, TE012, etc., is two to three times higher than the Q for mode shapes TM010, etc.
So it is very concerning that the Q for mode shape TM013 is being estimated by the moderator as 244,000.
The Q for mode shapes TM010, TM011, TM012, TM013 are supposed to be much lower than the Q for mode shapes TE012 and TE013 claimed by Shawyer and by Yang to be used for their frustums.
So, if a Q for mode shape TE012 or TE013 is 80,000 to 100,000 for a perfect geometry, then the Q for mode shape TM013 should 40,000 to 50,000 at most instead of the value of 244,000 estimated by the moderator. -
#2808 by frobnicat on 28 May, 2016 14:14
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.../...
It is trivial to show that black body radiation is a form of photon radiation that is less efficient than a perfectly collimated photon rocket (since photons participating in black body radiation are not high in the energy spectrum).
.../...
Wholeheartedly agree to the rest of your post, but allow me to ask/propose a clarification specifically about the efficiency related to energy of photons : in the frame of the emitter a given photon carries away a momentum p=hυ/c for a loss of energy E=hυ. Thrust (in Newtons) is momentum impulses per second and spent power is energy packets per second, hence Thrust/Power(in N/W)=(hυ/c)/hυ=1/c
The efficiency as "figure of merit" in terms of Thrust/Power ratio doesn't depend on frequency (or proportionately to Planck constant, on energy) of single photons. What would depend (in the case of blackbody radiation) on temperature is the magnitude of radiated power for emitter of a given cross section. Thus a black-body emitter radiating in the "white hot" (say tungsten heated at 2400K) would radiate (in deep space) much more Watts (and by that have much more thrust) that the same body just in far infra red (just warm to the touch), but thrust/power is the same.
BTW the far infrared photons of a warm to the touch dissipating EM drive frustum in deep space are much higher on the energy scale than the original photons of the microwaves that dissipated by losses in the copper. The thermodynamics unenlightened in me finds that aspect fascinating...
What might limit the efficiency (in N/W) of unintentionally asymmetric waste heat radiation pressure compared to perfectly collimated photon rocket (whatever the photons, visible light ok, X ray ok, microwaves ok, same efficiency bound in principle) is the collimation : waste heat usually radiates in all directions and isn't collimated in near parallel rays.
In all circumstances thrust/power of 1/c (3.33µN/kW) is an upper bound for "self powered radiation propulsion".
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#2809 by Rodal on 28 May, 2016 14:17
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.../...
It is trivial to show that black body radiation is a form of photon radiation that is less efficient than a perfectly collimated photon rocket (since photons participating in black body radiation are not high in the energy spectrum).
.../...
Wholeheartedly agree to the rest of your post, but allow me to ask/propose a clarification specifically about the efficiency related to energy of photons : in the frame of the emitter a given photon carries away a momentum p=hυ/c for a loss of energy E=hυ. Thrust (in Newtons) is momentum impulses per second and spent power is energy packets per second, hence Thrust/Power(in N/W)=(hυ/c)/hυ=1/c
The efficiency as "figure of merit" in terms of Thrust/Power ratio doesn't depend on frequency (or proportionately to Planck constant, on energy) of single photons. What would depend (in the case of blackbody radiation) on temperature is the magnitude of radiated power for emitter of a given cross section. Thus a black-body emitter radiating in the "white hot" (say tungsten heated at 2400K) would radiate (in deep space) much more Watts (and by that have much more thrust) that the same body just in far infra red (just warm to the touch), but thrust/power is the same.
BTW the far infrared photons of a warm to the touch dissipating EM drive frustum in deep space are much higher on the energy scale than the original photons of the microwaves that dissipated by losses in the copper. The thermodynamics unenlightened in me finds that aspect fascinating...
What might limit the efficiency (in N/W) of unintentionally asymmetric waste heat radiation pressure compared to perfectly collimated photon rocket (whatever the photons, visible light ok, X ray ok, microwaves ok, same efficiency bound in principle) is the collimation : waste heat usually radiates in all directions and isn't collimated in near parallel rays.
In all circumstances thrust/power of 1/c (3.33µN/kW) is an upper bound for "self powered radiation propulsion".
You are correct, thank you for taking your time to point it out. Thrust is higher with radiating higher power but what was being discussed was the figure of merit: thrust/power remains unchanged. I corrected the original post accordingly, as collimation is what will affect the figure of merit, and not the frequency of the photons.
The fact that in all circumstances thrust/power of 1/c (3.33µN/kW) is an upper bound for "self powered radiation propulsion" is a very neat result, and continues to be one of the most valuable lessons in these threads.
There is no way out of this unless there is an external source of force/energy, thus Shawyer's explanation is a non-starter. People may argue whether Dr. White's degradable and mutable Quantum Vacuum, or Dr. McCulloch Unruh effect, or Prof. Woodward Mach Effect (the inertial effect on the drive of all the bodies in the Cosmos, no matter how far) can actually exist and be operational, but such discussions are at a higher level, as Shawyer's explanation just contradicts what Shawyer assumes in the first place: it contradicts his use of Maxwell's equations and Special Relativity. Shawyer's explanation is self-inconsistent.
Shawyer's explanation ignores basic known facts about Maxwell's equations:
1) Maxwell's equations already satisfy (without any extra statements) Special Relativity and hence Lorentz transformations.
2) Maxwell's equations already satisfy (without any extra statements) conservation of energy and conservation of momentum.
This is why the scientific community reacted the way they did to Shaywer's article in New Scientist 2006.
If the EM Drive is capable of what is claimed, something beyond Maxwell's equations and Special Relativity is needed.
Thus Chris Bergin was correct to move the entire contents of these threads out of "Advanced Concepts" into something called "New Physics", as what EM Drive experimenters claim runs contrary to the physics of Maxwell and Special Relativity. Dr. White, McCulloch, Woodward, Puthoff and others understand that.
If the EM Drive works for space propulsion better than a photon rocket, it must be due to something that Shawyer did not consider. There are many such examples in Physics: Arno Penzias and Robert Woodrow Wilson received the Nobel prize for "discovering the microwave background radiation" that they thought was due to pesky noise from birds drops on their microwave dish. Wilson and Penzias had the birds trapped and then cleaned the equipment, but the signals continued.
http://www.smithsonianmag.com/smithsonian-institution/how-scientists-confirmed-big-bang-theory-owe-it-all-to-a-pigeon-trap-180949741/?no-ist
A big difference is that Penzias and Wilson promptly corrected their views on the source of the noise, and Penzias and Wilson understood what is the microwave background radiation while Shawyer is still insisting in his not-self-consistent explanation, and ignoring instead of addressing the criticism.
When the original inventor insists on an explanation that is not self-consistent, does not specifically address the criticism (i.e. what is the privileged frame he uses for Kinetic Energy) and has not reported a single experiment in partial vacuum (to eliminate thermal convection effects), not a single experiment using a torsional pendulum (the instrument of choice in Aerospace micro-thrusters and for gravitation experiments) and not a single experiment using batteries instead of power cords, it is not surprising that the EM Drive is still a subject of such debate after more than 15 years of starting SPR Ltd.
By contrast, Penzias and Wilson addressed all the sources of noise, learned about the microwave background radiation and the rest is history. -
#2810 by Eusa on 28 May, 2016 17:03
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I've got some new ideas based on my theory of a QG Drive. (QuantumGravity). Thoughts are connected on using a microwave cavity and resonant conducter...
It could be useful insert some narrow cut cone -shaped waveguides in the cavity (thin conducter material). For example four waveguides vertically centrally with length 3/5 of cavity inner height and with a TE225 mode (in waveguides TE113)... And spherical ends of course. -
#2811 by dustinthewind on 28 May, 2016 17:07
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So if we change the speed of light upon impact then we change the thrust per power ratio? Supposing upon impact the photon is slowed to c/2 then that gives 6.66µN/kW?.../...
It is trivial to show that black body radiation is a form of photon radiation that is less efficient than a perfectly collimated photon rocket (since photons participating in black body radiation are not high in the energy spectrum).
.../...
Wholeheartedly agree to the rest of your post, but allow me to ask/propose a clarification specifically about the efficiency related to energy of photons : in the frame of the emitter a given photon carries away a momentum p=hυ/c for a loss of energy E=hυ. Thrust (in Newtons) is momentum impulses per second and spent power is energy packets per second, hence Thrust/Power(in N/W)=(hυ/c)/hυ=1/c
The efficiency as "figure of merit" in terms of Thrust/Power ratio doesn't depend on frequency (or proportionately to Planck constant, on energy) of single photons. What would depend (in the case of blackbody radiation) on temperature is the magnitude of radiated power for emitter of a given cross section. Thus a black-body emitter radiating in the "white hot" (say tungsten heated at 2400K) would radiate (in deep space) much more Watts (and by that have much more thrust) that the same body just in far infra red (just warm to the touch), but thrust/power is the same.
BTW the far infrared photons of a warm to the touch dissipating EM drive frustum in deep space are much higher on the energy scale than the original photons of the microwaves that dissipated by losses in the copper. The thermodynamics unenlightened in me finds that aspect fascinating...
What might limit the efficiency (in N/W) of unintentionally asymmetric waste heat radiation pressure compared to perfectly collimated photon rocket (whatever the photons, visible light ok, X ray ok, microwaves ok, same efficiency bound in principle) is the collimation : waste heat usually radiates in all directions and isn't collimated in near parallel rays.
In all circumstances thrust/power of 1/c (3.33µN/kW) is an upper bound for "self powered radiation propulsion".
Also with the polarizable vacuum equations p*E is constant so then p/E is not. p(K)=po*K^(1/2) and E=Eo/K^(1/2) then p/E gives p/E(K)=po/Eo*K. https://arxiv.org/ftp/gr-qc/papers/9909/9909037.pdf "Polarizable-Vacuum (PV) representation of general relativity, H. E. Puthoff " (realized later P(K) is only to 1/2 power not 3/2). It is interesting that the K value changes as K=ro^2/r^2 such that the µN/kW would change with distance squared from a gravitating body. -
#2812 by Gilbertdrive on 28 May, 2016 17:15
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I've read there is a sort of privileged frame, and space, the vacuum itself is the road...
http://arxiv.org/pdf/0708.3519v4Quote"Consider that the vacuum medium is described by the vacuum states of
quantum fields and then its total momentum vanishes, it is reasonable for us to assume that
the vacuum medium as a whole is always resting with respect to all inertial observers. In
other words, the relative velocity between the vacuum medium and an arbitrary inertial
observer cannot be measured (i.e., it is an unobservable quantity), such that one can think it
always vanishes. On the other hand, consider that the velocity of light in vacuum is
invariant with respect to all inertial observers, and the eigenvalues of electron’s velocity
operator are equal to the velocity of light in vacuum, one can present the following
hypotheses: the velocity of light in vacuum ( 1 c = ) and the velocity of the vacuum medium
( ) are only two genuine velocities in our universe, they are invariant constants for all
inertial frames of reference; all other velocities are the apparent (or average) velocities of
massless fields moving in a zigzag manner. Such a zigzag motion, just as the
electromagnetic waves that are reflected back and forth by perfectly conducting walls as
they propagate along the length of a hollow waveguide, concerns two mutually orthogonal
0 u =
114D momentum components, i.e., a time-like 4D momentum (called the longitudinal
component) and a space-like 4D momentum (called the transverse component), respectively,
where the former corresponds to the usual 4D momentum of particles while the latter
contributes to the rest mass of particles."
There are several ways of interacting with the vacuum that were mentionned and discussed in these threads. For example The degradable quantum vacuum, or some new forms of the old Aether theories. But they are all new physics, or at least non standard physics. The point is that, in standard GR, there is no way to push against space like against a road.
So, the main point, the main problem with Shawyer, is that he claims that his explanations work with standard physics. If he thinks that there is a way to push against space, he should explicit it in his "Emdrive Basis" and he should recognize that it is non-standard physics. Something else than GR.
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#2813 by X_RaY on 28 May, 2016 18:02
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I've got some new ideas based on my theory of a QG Drive. (QuantumGravity). Thoughts are connected on using a microwave cavity and resonant conducter...
Interesting idea. Please note the following:
It could be useful insert some narrow cut cone -shaped waveguides in the cavity (thin conducter material). For example four waveguides vertically centrally with length 3/5 of cavity inner height and with a TE225 mode (in waveguides TE113)... And spherical ends of course.
Any inner structures inside the cavity will shift the resonant natural frequency of all modes and increase losses* and therefore lowers the Q.
https://forum.nasaspaceflight.com/index.php?topic=38577.msg1455560#msg1455560
*For dielectric materials this is due to the tanδ.
*For the case of additional conductive materials in the cavity the surface to volume relation will be more worse, therefore ohmic losses will increase. -
#2814 by Eusa on 28 May, 2016 19:17
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But in my theory both the pure form of standing wave and the energy content do matter. The right form of radiation field is more important to achieve the spacetime warping effect.I've got some new ideas based on my theory of a QG Drive. (QuantumGravity). Thoughts are connected on using a microwave cavity and resonant conducter...
Interesting idea. Please note the following:
It could be useful insert some narrow cut cone -shaped waveguides in the cavity (thin conducter material). For example four waveguides vertically centrally with length 3/5 of cavity inner height and with a TE225 mode (in waveguides TE113)... And spherical ends of course.
Any inner structures inside the cavity will shift the resonant natural frequency of all modes and increase losses* and therefore lowers the Q.
https://forum.nasaspaceflight.com/index.php?topic=38577.msg1455560#msg1455560
*For dielectric materials this is due to the tanδ.
*For the case of additional conductive materials in the cavity the surface to volume relation will be more worse, therefore ohmic losses will increase.
Hence, if lowering Q makes it possible to get more beautiful standing wave remaining as much as possible longitudinal components of magnetic components, it's worth of implement.
Secondly, the optimal wave form reduce energy loss in respect of the power of effect... -
#2815 by FattyLumpkin on 28 May, 2016 19:45
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dustinthewind, I am confused about the concept/analogy you made re the laser photonic thruster or perhaps have missed your point entirely. As noted in the video and in the image (attached) there are two mirrors (both moving) one faster than the other: The "slower" moving (first) reflector which apparently is also producing energy for the laser appears to employ conventional propulsion (chemical) for thrust, and the "spacecraft" although moving faster acts entirely as a (second) reflector. Relative to one another the spacecraft is increasing in velocity more quickly than the "main laser/reflector chemical rocket". The spacecraft is being "pushed" by the main laser/mirror/chemical stage. Certainly this would be the red-shifting and decrease in thrust going on in this configuration/concept, yet there is no cavity. The questions of COE or COM do not arise here. Would you please explain where I'm wrong in this? I just don't see where/how this LPR can be compared with the close resonant cavity. Of course anyone please jump in to straiten me out. LOL FL
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#2816 by X_RaY on 28 May, 2016 19:52
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I am not really familar with your theory. Have you a paper about to share (or if already available here the link to the specific post)?
But in my theory both the pure form of standing wave and energy contents does matter. The right form of radiation field is more important to achieve the spacetime warping effect.I've got some new ideas based on my theory of a QG Drive. (QuantumGravity). Thoughts are connected on using a microwave cavity and resonant conducter...
Interesting idea. Please note the following:
It could be useful insert some narrow cut cone -shaped waveguides in the cavity (thin conducter material). For example four waveguides vertically centrally with length 3/5 of cavity inner height and with a TE225 mode (in waveguides TE113)... And spherical ends of course.
Any inner structures inside the cavity will shift the resonant natural frequency of all modes and increase losses* and therefore lowers the Q.
https://forum.nasaspaceflight.com/index.php?topic=38577.msg1455560#msg1455560
*For dielectric materials this is due to the tanδ.
*For the case of additional conductive materials in the cavity the surface to volume relation will be more worse, therefore ohmic losses will increase.
Hence, if lowering Q makes it possible to get more beautiful standing wave remaining as much as possible longitudinal components of magnetic components, it's worth of implement.
Secondly, the optimal wave form reduce energy loss in respect of the power of effect...
Nevertheless, lower Q means lower energy density in the field.
Also especially additional metallic parts tend to deform the the mode because of the field have to satisfy the boundary conditions. That means to satisfy your "beautiful standing wave" the dimsions like cone angle and curving of the endplates should be corrected in this regard?
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#2817 by Eusa on 28 May, 2016 20:00
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Trying ascii graphics because I'm mobile right now.
Fine. It works. There is the idea. Waveguides fill the middle of the cavity, not from end to end. -
#2818 by mwvp on 28 May, 2016 20:26
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I've read there is a sort of privileged frame, and space, the vacuum itself is the road...
http://arxiv.org/pdf/0708.3519v4Quote"Consider that the vacuum medium is described by the vacuum states of
quantum fields and then its total momentum vanishes, it is reasonable for us to assume that
the vacuum medium as a whole is always resting with respect to all inertial observers. In
other words, the relative velocity between the vacuum medium and an arbitrary inertial
observer cannot be measured (i.e., it is an unobservable quantity), such that one can think it
always vanishes. On the other hand, consider that the velocity of light in vacuum is
invariant with respect to all inertial observers, and the eigenvalues of electron’s velocity
operator are equal to the velocity of light in vacuum, one can present the following
hypotheses: the velocity of light in vacuum ( 1 c = ) and the velocity of the vacuum medium
( ) are only two genuine velocities in our universe, they are invariant constants for all
inertial frames of reference; all other velocities are the apparent (or average) velocities of
massless fields moving in a zigzag manner. Such a zigzag motion, just as the
electromagnetic waves that are reflected back and forth by perfectly conducting walls as
they propagate along the length of a hollow waveguide, concerns two mutually orthogonal
0 u =
114D momentum components, i.e., a time-like 4D momentum (called the longitudinal
component) and a space-like 4D momentum (called the transverse component), respectively,
where the former corresponds to the usual 4D momentum of particles while the latter
contributes to the rest mass of particles."
There are several ways of interacting with the vacuum that were mentionned and discussed in these threads. For example The degradable quantum vacuum, or some new forms of the old Aether theories. But they are all new physics, or at least non standard physics. The point is that, in standard GR, there is no way to push against space like against a road.
Agreed, at least directly or first-hand. And I infer the authors of the paper I quoted will agree too, for they state:Quotethe relative velocity between the vacuum medium and an arbitrary inertial
observer cannot be measured (i.e., it is an unobservable quantity), such that one can think it
always vanishes.
Now, you can hardly push on something that cannot even be "measured", being an "unobservable quantity", that "always vanishes".
Yet,
Space, the vacuum, that immeasurable, unobservable, vanishing quantity supports fields that manifest as particles that can be measured, observed and are apparent, and that we build rockets out of, and describe with Einstein's and Maxwell's equations. So we polarize, excite and react against it with other modes of polarized, excited energy propagating through it. Very interesting paper, wish I could understand much more of it.So, the main point, the main problem with Shawyer, is that he claims that his explanations work with standard physics. If he thinks that there is a way to push against space, he should explicit it in his "Emdrive Basis" and he should recognize that it is non-standard physics. Something else than GR.
I think Shawyer should be far, far more forthcoming because I believe he's keeping trade secrets.
There are alternatives between Shawyer's present flawed theory and the need for non-standard physics, as I've presented over the months I've striven here, though not often to you personally Gilbertdrive.
Theoretical strawmen can be setup, hacked and burned. Pinatas of Shawyer can be bashed. Emulation is said to be the sincerest form of flattery. Trees are known by their fruit, and wisdom of her children. -
#2819 by Rodal on 28 May, 2016 20:30
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dustinthewind, I am confused about the concept/analogy you made re the laser photonic thruster or perhaps have missed your point entirely. As noted in the video and in the image (attached) there are two mirrors (both moving) one faster than the other: The "slower" moving (first) reflector which apparently is also producing energy for the laser appears to employ conventional propulsion (chemical) for thrust, and the "spacecraft" although moving faster acts entirely as a (second) reflector. Relative to one another the spacecraft is increasing in velocity more quickly than the "main laser/reflector chemical rocket". The spacecraft is being "pushed" by the main laser/mirror/chemical stage. Certainly this would be the red-shifting and decrease in thrust going on in this configuration/concept, yet there is no cavity. The questions of COE or COM do not arise here. Would you please explain where I'm wrong in this? I just don't see where/how this LPR can be compared with the close resonant cavity. Of course anyone please jump in to straiten me out. LOL FL
You are entirely correct that the problems with Conservation of Momentum and Conservation of Energy which plague the EM Drive do not arise in the Photonic Laser Thruster.
Not only there is no cavity, but what is worse is that the photonic laser thruster consists of one vehicle that must travel backward for the main vehicle to move forward. Thus, for the photonic laser thruster to go far one needs a huge infrastructure of resource vehicles placed ahead of time in its travel path (how did those vehicles get there in the first place? -- they must use other forms of propulsion to get there in the first place !!!) because the photonic laser thruster efficiency decreases with distance between the two vehicles to the point that for the main vehicle to continue moving forward it needs newer resource vehicles to thrust itself. This has been recognized by the inventor.