Author Topic: EM Drive Developments - related to space flight applications - Thread 9  (Read 1079236 times)

Online WarpTech

  • Full Member
  • ****
  • Posts: 1223
  • Do it!
  • Vista, CA
  • Liked: 1290
  • Likes Given: 1740
Another article from Ethan Seigal on the Forbes website:

http://www.forbes.com/sites/startswithabang/2016/11/30/could-dark-matter-be-powering-the-emdrive/#25e019901e53

Interesting conjecture that instead of pushing against the QV (which Woodward tells us the EMDrive can't do), the drive is instead expelling dark matter like a normal rocket through photon-axion interaction.

"How would it work? At any point in time, there are dark matter particles passing through all regions of space, undeterred by the presence of matter or other Standard Model particles. Inside the electromagnetic cavity, photons of a particular frequency bounce around in all directions, conserving momentum and generating no thrust. But if photons moving in a particular direction — towards the ‘back’ of the cavity, for example — are likely to strike a dark matter particle, three things ensue:

1) The photon changes momentum, and moves “less backwards” and “more forwards” than before it struck the dark matter particle.
2) The photon strikes the inside wall of the cavity, reflecting off of it and imparting its momentum in the forward direction to the cavity itself.
3) The struck dark matter particle gains momentum as well in the opposite direction: backwards.

Momentum is conserved because the dark matter carries it away, equal and opposite in magnitude to what the cavity absorbs."


I think it is much more likely and practical, that momentum is carried into the copper and through it by magnetic flux, which pass through due to the voltage drop (losses) from resistance and current.

Offline OnlyMe

  • Full Member
  • ***
  • Posts: 300
  • So. Calif.
  • Liked: 165
  • Likes Given: 178
For those considering building a YBCO based frustum, as I am, here are 2 interesting graphs:

1st is 2015 data showing max H field vs temp vs various superconductors. From this data it would seem that YBCO is the champ material for dealing with high H field, which suggests it can handle very high Q frustum builds.

2nd is 2009 data from Roger Shawyer showing YBCO Rs vs various temperatures at 3.85GHz. Note that the ~78uOhm value in 2009 is now 3uOhm in 2016.

While LNe is somewhat expensive, it does appear to offer a 5x lower Rs (5x higher Q) and 2.5x higher max Hc so maybe worth giving it a shot?

For sure design for LN2 and if you need to go further maybe consider LNe instead of LH2 or LHe?
YBCO is a ceramic compound. The gap to excitations that leads to superconductivity is a result of pairs of electrons (or other fermions) bound together at (very) low temperatures, and thats in the case of ceramic superconductors usualy a surface effect. If a magnetic field is close to  these type of  superconductors  the effect will be lost. (meissner ochsenfeld effect)  as the frustrum works with a crude coil as rf transmitter , so how does Shawyer prevent magnetic interference and loss of superconductivity?

Very good question(s). From what I have read in these discussions and the limited information available from a few of Shawyer's papers/patent, upscalling the frustum to a superconducting cryogenic design is based on an assumption that high Q is the dominant factor in developing high thrust. Without any published experimental data involving a superconducting EmDrive design, it appears to me to be a theoretical leap of faith.

So the short answer is there seems to be a race by some to try and be the first, which demands an almost blind faith in conclusions based on flawed or incomplete theoretical interpretations of .....

I do tend to run on and often present off the wall observations and interpretations of my own, so in the spirit of old maps, "be warned beyond here there be dragons!"

As a non-expert in any of the areas specific to the design and construction of a functional device, and based only on what understanding I have been able to tease out of these discussions, it would seem far more productive to refine a room temperature design which if which of what information that has been made available should be able to developed thrusts in the Newton/Kw range, before chasing what seems purely theoretical upscalling based on what at present is very limited published data from mostly 1st to perhaps 3rd generation engineering attempts to recreate poorly described devices claiming up to triple digit mN/Kw results.

Any device that could consistently produce triple digit mN/Kw thrusts at room temperatures, would provide a far better basis for exploring any functionally measurable design and/or materials based aspects contributing to those results.

Right now from a peanut gallery observer, without better design blueprints from previously successful experiments, chasing superconducting promises of multi ton thrusts, just seems foolish.

The EW paper seems to have provided the first reliable data demonstrating repeatable thrust, but unless I am mistaken the frustum design and TM mode, in those tests, do not represent the only or perhaps even best approach, for obtaining higher room temperature thrusts.

Also I believe in Shawyer's last partnership patent, only the large flat end plate was coated with a superconducting material.

Offline TheTraveller

Here is something to consider.

If we input 1kW of Rf, the radiated heat energy by the frustum side walls and end caps is max 1kW of heat energy, minus any other energy conversions that may occur.

So there should be NO significant effect on sidewall and end plate eddy currents and the resultant heating as cavity Q increases.

Phil
« Last Edit: 12/01/2016 02:38 PM by TheTraveller »
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Offline TheTraveller

For those considering building a YBCO based frustum, as I am, here are 2 interesting graphs:

1st is 2015 data showing max H field vs temp vs various superconductors. From this data it would seem that YBCO is the champ material for dealing with high H field, which suggests it can handle very high Q frustum builds.

2nd is 2009 data from Roger Shawyer showing YBCO Rs vs various temperatures at 3.85GHz. Note that the ~78uOhm value in 2009 is now 3uOhm in 2016.

While LNe is somewhat expensive, it does appear to offer a 5x lower Rs (5x higher Q) and 2.5x higher max Hc so maybe worth giving it a shot?

For sure design for LN2 and if you need to go further maybe consider LNe instead of LH2 or LHe?
YBCO is a ceramic compound. The gap to excitations that leads to superconductivity is a result of pairs of electrons (or other fermions) bound together at (very) low temperatures, and thats in the case of ceramic superconductors usualy a surface effect. If a magnetic field is close to  these type of  superconductors  the effect will be lost. (meissner ochsenfeld effect)  as the frustrum works with a crude coil as rf transmitter , so how does Shawyer prevent magnetic interference and loss of superconductivity?

Very good question(s). From what I have read in these discussions and the limited information available from a few of Shawyer's papers/patent, upscalling the frustum to a superconducting cryogenic design is based on an assumption that high Q is the dominant factor in developing high thrust. Without any published experimental data involving a superconducting EmDrive design, it appears to me to be a theoretical leap of faith.

So the short answer is there seems to be a race by some to try and be the first, which demands an almost blind faith in conclusions based on flawed or incomplete theoretical interpretations of .....

I do tend to run on and often present off the wall observations and interpretations of my own, so in the spirit of old maps, "be warned beyond here there be dragons!"

As a non-expert in any of the areas specific to the design and construction of a functional device, and based only on what understanding I have been able to tease out of these discussions, it would seem far more productive to refine a room temperature design which if which of what information that has been made available should be able to developed thrusts in the Newton/Kw range, before chasing what seems purely theoretical upscalling based on what at present is very limited published data from mostly 1st to perhaps 3rd generation engineering attempts to recreate poorly described devices claiming up to triple digit mN/Kw results.

Any device that could consistently produce triple digit mN/Kw thrusts at room temperatures, would provide a far better basis for exploring any functionally measurable design and/or materials based aspects contributing to those results.

Right now from a peanut gallery observer, without better design blueprints from previously successful experiments, chasing superconducting promises of multi ton thrusts, just seems foolish.

The EW paper seems to have provided the first reliable data demonstrating repeatable thrust, but unless I am mistaken the frustum design and TM mode, in those tests, do not represent the only or perhaps even best approach, for obtaining higher room temperature thrusts.

Also I believe in Shawyer's last partnership patent, only the large flat end plate was coated with a superconducting material.

YBCO seems to have the highest Hc of any superconductor as I posted shortly ago.
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=41732.0;attach=1391109;image

The 60T indicated at LN2 temp is ~4.77x10^7 A/m.

As cavity TE013 H fields are max in the centre of the cavity, the side wall and end plate H fields are very low.

Please check back a few posts for the images.

Spherical cavity E * H fields:
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=41732.0;attach=1391125;image
« Last Edit: 12/01/2016 02:50 PM by TheTraveller »
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Offline zellerium

  • Full Member
  • *
  • Posts: 171
  • Pittsburgh, PA
  • Liked: 279
  • Likes Given: 400
See the attached for clarification. Note the force direction arrows in the bottom images that point to the end plate with the shortest 1/2 wave, that has the highest photon momentum & radiation pressure.

TT, you're showing data for Eagleworks' frustum with dielectric at small end and TE012 mode, where max E & H fields are located near small end.

Whereas zellerium, WarpTech and Star-Drive are discussing Eagleworks' frustum with dielectric at small end and TM212 mode, where max E & H fields are located near big end. Besides, in that particular mode only 10% of the RF energy resides in the PE discs.

Your "shorter vs longer 1/2 wave" conjecture may still apply, but the two field configurations are very different, and their max strength values are located opposite from each other.

We only have data for TE012 for both dielectric and non dielectric forces and direction.

It is which end has the shortest 1/2 that is of interest as the shortest 1/2 wave has the highest momentum and radiation pressure.

As Roger has shown, without dielectrics, as attached, the static force is generated small to big as Paul and I also measured and observed.

Any theory needs to be able to explain the force direction and why it swaps direction with and without dielectric when excited in the same mode.

I may be that where the highest energy density is located is not what is creating the measured static force with a direction big to small when a dielectric is at the small end.

Please note the measured force direction, big to small is the same for ALL the EW tests and seems to be mode independent.

The EW mode map I have seen has shown the TM212 dielectric frustum also has the shortest 1/2 wave at the small end, which is consistent with the measured force direction being big to small.

Zellerium's mode map in TM212 also shows the shortest 1/2 wave at the small end, which us consistent with the EW TM212 mode map.

TT,

For the NASA TE012 mode data, my theory did predict the reversed direction of force when the dielectric was added. However, the TM212 mode simulation that @zellerium just posted shows a different configuration of energy, wavelength and losses. IMO, the only issue is that I went by what was shown on the graphs as "Volume Loss Density", when I believe we should be looking at "Surface Loss Density", to have an accurate representation. Then it would be obvious that in the TM212 mode the majority of losses are at the big end, when the dielectric is present "shielding" the small end from those surface losses.

So one side has losses in the volume and the other has losses on the surface... But somehow the surface losses dissipate momentum differently than the volume losses?
If we wanted to optimize a cavity for thrust, would we want a balance between highest surface losses on one side, highest volume losses on the other side, and quality?


Online meberbs

  • Full Member
  • ****
  • Posts: 1227
  • Liked: 1141
  • Likes Given: 295
According to radiation pressure theory, the big to small accelerative force is the equal but opposite Reaction force to the small to big static Thrust force.
This is not "according to radiation pressure theory." This is from statements by Shawyer in a paper where he utterly fails at a Physics 101 force diagram.

I have asked you many, many times to answer simple questions about a simple mechanical setup (originally in this post), which you have refused to do. These questions are important to clarify the definitions of terms that you are using. You are confusing everyone because you are using the word force in a way that contradicts the definition of a force.

I ask again since this is the beginning of a new thread, and it would be nice to have some rational discourse.

Offline OnlyMe

  • Full Member
  • ***
  • Posts: 300
  • So. Calif.
  • Liked: 165
  • Likes Given: 178
For those considering building a YBCO based frustum, as I am, here are 2 interesting graphs:

1st is 2015 data showing max H field vs temp vs various superconductors. From this data it would seem that YBCO is the champ material for dealing with high H field, which suggests it can handle very high Q frustum builds.

2nd is 2009 data from Roger Shawyer showing YBCO Rs vs various temperatures at 3.85GHz. Note that the ~78uOhm value in 2009 is now 3uOhm in 2016.

While LNe is somewhat expensive, it does appear to offer a 5x lower Rs (5x higher Q) and 2.5x higher max Hc so maybe worth giving it a shot?

For sure design for LN2 and if you need to go further maybe consider LNe instead of LH2 or LHe?
YBCO is a ceramic compound. The gap to excitations that leads to superconductivity is a result of pairs of electrons (or other fermions) bound together at (very) low temperatures, and thats in the case of ceramic superconductors usualy a surface effect. If a magnetic field is close to  these type of  superconductors  the effect will be lost. (meissner ochsenfeld effect)  as the frustrum works with a crude coil as rf transmitter , so how does Shawyer prevent magnetic interference and loss of superconductivity?

Very good question(s). From what I have read in these discussions and the limited information available from a few of Shawyer's papers/patent, upscalling the frustum to a superconducting cryogenic design is based on an assumption that high Q is the dominant factor in developing high thrust. Without any published experimental data involving a superconducting EmDrive design, it appears to me to be a theoretical leap of faith.

So the short answer is there seems to be a race by some to try and be the first, which demands an almost blind faith in conclusions based on flawed or incomplete theoretical interpretations of .....

I do tend to run on and often present off the wall observations and interpretations of my own, so in the spirit of old maps, "be warned beyond here there be dragons!"

As a non-expert in any of the areas specific to the design and construction of a functional device, and based only on what understanding I have been able to tease out of these discussions, it would seem far more productive to refine a room temperature design which if which of what information that has been made available should be able to developed thrusts in the Newton/Kw range, before chasing what seems purely theoretical upscalling based on what at present is very limited published data from mostly 1st to perhaps 3rd generation engineering attempts to recreate poorly described devices claiming up to triple digit mN/Kw results.

Any device that could consistently produce triple digit mN/Kw thrusts at room temperatures, would provide a far better basis for exploring any functionally measurable design and/or materials based aspects contributing to those results.

Right now from a peanut gallery observer, without better design blueprints from previously successful experiments, chasing superconducting promises of multi ton thrusts, just seems foolish.

The EW paper seems to have provided the first reliable data demonstrating repeatable thrust, but unless I am mistaken the frustum design and TM mode, in those tests, do not represent the only or perhaps even best approach, for obtaining higher room temperature thrusts.

Also I believe in Shawyer's last partnership patent, only the large flat end plate was coated with a superconducting material.

YBCO seems to have the highest Hc of any superconductor as I posted shortly ago.

The 60T indicated at LN2 temp is ~4.77x10^7 A/m.

As cavity TE013 H fields are max in the centre of the cavity, the side wall and end plate H fields are very low.

Please check back a few posts for the images.

Spherical cavity E * H fields:
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=41732.0;attach=1391125;image

YBCO Hc field sensitivity vs temp:
http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=41732.0;attach=1391109;image

You are missing the point that this is all a theoretical leap of faith, that assumes there is nothing other than Q that affects the resultant thrust. The EM field being introduced into the frustum interacts with the materials of the frustum walls in more ways than just the Q achieved by design and frequency match. There are other differences between copper and YBCO than just Q.

For that matter has anyone tested how silver plating a polished copper frustum changes the developed thrust? Or even how any coating applied to the copper with the intent of reducing degradation affects performance.

DIY budgets don't often have the financial flexibility to run these kinds of incremental comparison experiments. Especially when a great deal of the design budgets have been consumed in attempts to address a never ending list of potential testing equipment design errors.

I was never interested in lab work. That does not mean I cannot see when or where what should be obvious incremental steps are being skipped, solely based on theoretical projections that have not been proven... Or if they have been proven, the proof is hidden behind walls of secrecy.

From the information provided so far, which is limited for certain, it still suggests that an optimized design of a room temperature copper frustum and microwave source, should produce enough thrust to be useful for satellites and when stacked even potentially manned moon and interplanetary missions.

If that is not the case, it seems to me the constant dangling of superconductor designs, functions more as a snipe hunt to keep everyone guessing and running in circles.

Build and test that self contained battery operated room temperature copper frustum and prove it works!

So far only Yang's first paper which seems suspicious, though potentially significant, EWs recent paper, that documented repeatable results with a less than optimum design and TM mode and a few rumored yet unpublished DIY results, indicate any real latent potential. Jumping from those to superconducting flying cars.., as I said sounds like a snipe hunt, certainly not good methodical science.
« Last Edit: 12/01/2016 03:26 PM by OnlyMe »

Offline TheTraveller

According to radiation pressure theory, the big to small accelerative force is the equal but opposite Reaction force to the small to big static Thrust force.
This is not "according to radiation pressure theory." This is from statements by Shawyer in a paper where he utterly fails at a Physics 101 force diagram.

I have asked you many, many times to answer simple questions about a simple mechanical setup (originally in this post), which you have refused to do. These questions are important to clarify the definitions of terms that you are using. You are confusing everyone because you are using the word force in a way that contradicts the definition of a force.

I ask again since this is the beginning of a new thread, and it would be nice to have some rational discourse.

Static force: Causes a scale or torsion pendulum to record a force acting against or with the scale or torsion pendulum. Equation F = (2 Qu Pwr Df) / c.

Dynamic force: Causes the free to accelerate acceleration of mass and is measured via F = A * M.

Can't measure both forces at the same time.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Online meberbs

  • Full Member
  • ****
  • Posts: 1227
  • Liked: 1141
  • Likes Given: 295
According to radiation pressure theory, the big to small accelerative force is the equal but opposite Reaction force to the small to big static Thrust force.
This is not "according to radiation pressure theory." This is from statements by Shawyer in a paper where he utterly fails at a Physics 101 force diagram.

I have asked you many, many times to answer simple questions about a simple mechanical setup (originally in this post), which you have refused to do. These questions are important to clarify the definitions of terms that you are using. You are confusing everyone because you are using the word force in a way that contradicts the definition of a force.

I ask again since this is the beginning of a new thread, and it would be nice to have some rational discourse.

I thought you'd know by now how TT will answer. The route this conversation takes goes as follows:

1) Statement that the theoretical explanations on offer are non-nonsensical
2) Contradictions are rebuffed by endorsing data above theory
3) Statements to the effect that all theories are flawed but the good ones still make physical sense
4) Appeal to the authority of Shawyer because he made EM Drive work
5) Go to 1
I know, I am just giving it one last shot in light of the new thread (and for casual readers who look through the first few pages of a thread), my response to #2 this time (unless TT changes his pattern, and actually answers my questions) is planned to be along the lines of "I am tired of this cycle but figured I would give it one last shot. Just know that in the future when no one counters your claims it is only because everyone has given up on you listening to reason."

Online meberbs

  • Full Member
  • ****
  • Posts: 1227
  • Liked: 1141
  • Likes Given: 295
According to radiation pressure theory, the big to small accelerative force is the equal but opposite Reaction force to the small to big static Thrust force.
This is not "according to radiation pressure theory." This is from statements by Shawyer in a paper where he utterly fails at a Physics 101 force diagram.

I have asked you many, many times to answer simple questions about a simple mechanical setup (originally in this post), which you have refused to do. These questions are important to clarify the definitions of terms that you are using. You are confusing everyone because you are using the word force in a way that contradicts the definition of a force.

I ask again since this is the beginning of a new thread, and it would be nice to have some rational discourse.

Static force: Causes a scale or torsion pendulum to record a force acting against or with the scale or torsion pendulum. Equation F = (2 Qu Pwr Df) / c.

Dynamic force: Causes the free to accelerate acceleration of mass and is measured via F = A * M.

Can't measure both forces at the same time.
That is not an answer to the questions I asked. That is just providing the same contradictory definitions, because no force measurement is static, they all start with an acceleration, and the torsion  pendulum and scale measure how much force is required to hold back the acceleration. The only way I know how to explain this more clearly is by example, but you refuse to actually work through the example with me.

As I said in reply to RotoSequence:
I am tired of this cycle but figured I would give it one last shot. Just know that in the future when no one counters your claims it is only because everyone has given up on you listening to reason.

Offline flux_capacitor

  • Full Member
  • ****
  • Posts: 546
  • France
  • Liked: 651
  • Likes Given: 902
I would like my simple question to be answered too:

What is causing the 1/2 wave to lengthen on one side and shorten on the other side, but a local variation of the wavelength?

Offline TheTraveller

According to radiation pressure theory, the big to small accelerative force is the equal but opposite Reaction force to the small to big static Thrust force.
This is not "according to radiation pressure theory." This is from statements by Shawyer in a paper where he utterly fails at a Physics 101 force diagram.

I have asked you many, many times to answer simple questions about a simple mechanical setup (originally in this post), which you have refused to do. These questions are important to clarify the definitions of terms that you are using. You are confusing everyone because you are using the word force in a way that contradicts the definition of a force.

I ask again since this is the beginning of a new thread, and it would be nice to have some rational discourse.

Static force: Causes a scale or torsion pendulum to record a force acting against or with the scale or torsion pendulum. Equation F = (2 Qu Pwr Df) / c.

Dynamic force: Causes the free to accelerate acceleration of mass and is measured via F = A * M.

Can't measure both forces at the same time.
That is not an answer to the questions I asked. That is just providing the same contradictory definitions, because no force measurement is static, they all start with an acceleration, and the torsion  pendulum and scale measure how much force is required to hold back the acceleration. The only way I know how to explain this more clearly is by example, but you refuse to actually work through the example with me.

As I said in reply to RotoSequence:
I am tired of this cycle but figured I would give it one last shot. Just know that in the future when no one counters your claims it is only because everyone has given up on you listening to reason.

For sure there is movement.

In the EW torsion pendulum a few um.

On a scale a lot less movement as the mass is reacting against a strain gauge.

If you are asking me what is it pushing against to generate the force, well that is where we will probably never agree until you see an EmDrive levitate.

Nevertheless, the experimental data from EW and Roger are very clear as to the direction of the generated static force that acts on a scale or stiff torsion pendulum to record the level of the generated force.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Offline TheTraveller

I would like my simple question to be answered too:

What is causing the 1/2 wave to lengthen on one side and shorten on the other side, but a local variation of the wavelength?

In a resonant frustum, guide wavelength increases as the tapered waveguide diameter decreases, the group velocity decreases as does the radiation pressure it can generate on a end plate.

This is all existing microwave engineering.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Offline TheTraveller

You are missing the point that this is all a theoretical leap of faith, that assumes there is nothing other than Q that affects the resultant thrust. The EM field being introduced into the frustum interacts with the materials of the frustum walls in more ways than just the Q achieved by design and frequency match. There are other differences between copper and YBCO than just Q

For sure there are other factors. Like the Rs vs freq scaling factor and the Rs vs temp scaling factor. However as a general guide the measured Rs for room temp Cu is ~15,000uOhm and I have been offered YBCO with a 3uOhm at 3.85GHz and 77K, which is a drop of 5,000x.

So estimated Q should increase around 5,000x assuming the YBCO is being working well with-in it's temp and Hc limits.

Then there are Kilpatrick limits on the max E field before the air starts to break down from 100MV/m E fields. So there are engineering issues that need to be addressed but it is not like this is unknown territory.

The experimental data, adjusted for specific force, shows the force scales with Power and Q as attached. My own experimental data suggests the data is real.

Others may have their own opinion and ask for more data. I have no issue with that as I working to provide it.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Online meberbs

  • Full Member
  • ****
  • Posts: 1227
  • Liked: 1141
  • Likes Given: 295
I would like my simple question to be answered too:

What is causing the 1/2 wave to lengthen on one side and shorten on the other side, but a local variation of the wavelength?
That I can help with. The guide wavelength in a waveguide is basically due to the waves bouncing back and forth between the walls rather than straight down the middle. The superposition hides the non-axial portion, so you just see an apparently stretched axial wavelength, while the actual travelling waves maintain their original wavelength. In a smaller waveguide the angle of the bounces is steeper (for the same frequency of radiation), so the apparent wavelength gets longer. What Cullen originally showed was simply that the steeper the bounces, the less of the wave's momentum is in the axial direction, which is a very sensible result.

Something similar happens in an emDrive cavity as waves reflecting off the side walls cause the angles to get steeper towards the small end. You can't easily define a guide wavelength though because at any point the suprimposed waves are not all moving in the same direction, and it is not clear what modes (if any) the apparent standing wave has any meaningful relation to the angles the travelling waves are travelling at. The issue with this description and how Shawyer abuses Cullen's results is that by conservation of momentum, it is obvious that any change in axial momentum due to reflections off the sidewalls transfers that momentum to the sidewalls to end up with no net motion.

(Note:This post used simplified descriptions, to give an intuitive sense of what is going on. Boundary conditions and the wave equation make this more complicated than presented here.)

Offline Bob012345

  • Full Member
  • ****
  • Posts: 513
  • Liked: 103
  • Likes Given: 179
Another article from Ethan Seigal on the Forbes website:

http://www.forbes.com/sites/startswithabang/2016/11/30/could-dark-matter-be-powering-the-emdrive/#25e019901e53

Interesting conjecture that instead of pushing against the QV (which Woodward tells us the EMDrive can't do), the drive is instead expelling dark matter like a normal rocket through photon-axion interaction.

"How would it work? At any point in time, there are dark matter particles passing through all regions of space, undeterred by the presence of matter or other Standard Model particles. Inside the electromagnetic cavity, photons of a particular frequency bounce around in all directions, conserving momentum and generating no thrust. But if photons moving in a particular direction — towards the ‘back’ of the cavity, for example — are likely to strike a dark matter particle, three things ensue:

1) The photon changes momentum, and moves “less backwards” and “more forwards” than before it struck the dark matter particle.
2) The photon strikes the inside wall of the cavity, reflecting off of it and imparting its momentum in the forward direction to the cavity itself.
3) The struck dark matter particle gains momentum as well in the opposite direction: backwards.

Momentum is conserved because the dark matter carries it away, equal and opposite in magnitude to what the cavity absorbs."


I think it is much more likely and practical, that momentum is carried into the copper and through it by magnetic flux, which pass through due to the voltage drop (losses) from resistance and current.

Interesting. In a relativistic photon rocket, the transfer of energy to momentum nears 100% efficiency as the rocket nears c. I've always wondered if the surface effects in a resonant cavity act like a highly relativistic photon rocket transferring photon energy to momentum of the surface plasmons  much higher than 1/c which then push the cavity as a whole. If that were the case, it would be a much simpler model and well within the mainstream of current physics.

Offline Bob012345

  • Full Member
  • ****
  • Posts: 513
  • Liked: 103
  • Likes Given: 179
According to radiation pressure theory, the big to small accelerative force is the equal but opposite Reaction force to the small to big static Thrust force.
This is not "according to radiation pressure theory." This is from statements by Shawyer in a paper where he utterly fails at a Physics 101 force diagram.

I have asked you many, many times to answer simple questions about a simple mechanical setup (originally in this post), which you have refused to do. These questions are important to clarify the definitions of terms that you are using. You are confusing everyone because you are using the word force in a way that contradicts the definition of a force.

I ask again since this is the beginning of a new thread, and it would be nice to have some rational discourse.

I thought you'd know by now how TT will answer. The route this conversation takes goes as follows:

1) Statement that the theoretical explanations on offer are non-nonsensical
2) Contradictions are rebuffed by endorsing data above theory
3) Statements to the effect that all theories are flawed but the good ones still make physical sense
4) Appeal to the authority of Shawyer because he made EM Drive work
5) Go to 1
I know, I am just giving it one last shot in light of the new thread (and for casual readers who look through the first few pages of a thread), my response to #2 this time (unless TT changes his pattern, and actually answers my questions) is planned to be along the lines of "I am tired of this cycle but figured I would give it one last shot. Just know that in the future when no one counters your claims it is only because everyone has given up on you listening to reason."

Data is above theory. Throwing out solid data that doesn't 'fit' current theory is not good science. Of course the key is having good reliable data not just any data. That's what NASA tried to do.

Offline Bob012345

  • Full Member
  • ****
  • Posts: 513
  • Liked: 103
  • Likes Given: 179
According to radiation pressure theory, the big to small accelerative force is the equal but opposite Reaction force to the small to big static Thrust force.
This is not "according to radiation pressure theory." This is from statements by Shawyer in a paper where he utterly fails at a Physics 101 force diagram.

I have asked you many, many times to answer simple questions about a simple mechanical setup (originally in this post), which you have refused to do. These questions are important to clarify the definitions of terms that you are using. You are confusing everyone because you are using the word force in a way that contradicts the definition of a force.

I ask again since this is the beginning of a new thread, and it would be nice to have some rational discourse.

Any closed mechanical system should not provide a means to generate net momentum yet an electromagnetic system might since it is related to relativity, quantum field theory and at least weakly to gravitation.

Offline Notsosureofit

  • Full Member
  • ****
  • Posts: 656
  • Liked: 704
  • Likes Given: 1361
FYI:
http://scitation.aip.org/content/aip/magazine/physicstoday/article/69/12/10.1063/PT.3.3397?
utm_source=Physics%20Today&utm_medium=email&utm_campaign=7773957_December%202016%20Table%2
0of%20Contents&utm_content=Feat5&dm_i=1Y69,4MMF9,E1MTSN,H8E4P,1
« Last Edit: 12/01/2016 08:53 PM by Chris Bergin »

Offline PotomacNeuron

  • Full Member
  • *
  • Posts: 173
  • Do I look like a neuroscientist?
  • MD
  • Liked: 103
  • Likes Given: 24
FYI:


I was surprised that I had never heard of this powerful accelerator. Then I realize I am not the only one who have not.
« Last Edit: 12/01/2016 08:53 PM by Chris Bergin »
I am working on the ultimate mission human beings are made for.

Tags: