Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1879887 times)

Offline sghill

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Quick question.

In my physics education.  "Q" stood for heat energy, or charge, or resonance efficiency, depending on what you are talking about.

In most of these EMDrive conversations, the distinction hasn't been particularly worrisome, but I find myself asking what does "Q" mean in the context of these latest conversations.  Relatedly, is the definition of "Q" interchangeable in this context?

Thanks.
Bring the thunder Elon!

Offline Rodal

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Quick question.

In my physics education.  "Q" stood for heat energy, or charge, or resonance efficiency, depending on what you are talking about.

In most of these EMDrive conversations, the distinction hasn't been particularly worrisome, but I find myself asking what does "Q" mean in the context of these latest conversations.  Relatedly, is the definition of "Q" interchangeable in this context?

Thanks.

Take Q to stand for "quality of resonance factor", a dimensionless quantity, which is inverse to damping: see https://en.wikipedia.org/wiki/Q_factor  in this thread, unless otherwise defined.

Q= 1 / (2 DampingRatio)  (where https://en.wikipedia.org/wiki/Damping_ratio )



Black spring= high Q, low damping
Blue spring= low  Q, high damping



____

(*) In general, Q it is not directly interchangeable with heat in this context (remember, Q is inverse to damping), except that energy dissipated by damping goes into heat
« Last Edit: 06/16/2015 03:49 PM by Rodal »

Offline madsci

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  Haha, cute gif  :)

Offline Rodal

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I've updated my Theory on the Wiki.

http://emdrive.wiki/Todd_Desiato_(@WarpTech)%27s_Evanescent_Wave_Theory#Application_of_Theory_to_the_EmDrive

The EM Drive is intentionally designed to have asymmetrical attenuation. As such, energy is reflected from the large end to be stored at the small end as induced currents. Standing waves store energy and as such, store mass. As the EM drive charges and the Q ramps up, energy from the input source is reflected from the large end and stored in the small end on each successive reflection cycle. This energy is stored as induction currents caused by the near-field effects of evanescent waves. Due to the phase shift, the Power Factor is not zero as it is with standing waves. Therefore, work can be done to move the EM Drive. This dynamic action of storing mass-energy toward the front causes the center of mass to walk forward. The increasing pressure on the small end causes the EM Drive to accelerate forward due to the internal pressure gradient, until the pressure is equalized. Then the cycle builds again. This dynamic implies that a high Q value is not required, but rather how quickly can energy be ramped up under extreme attenuation conditions.
Todd
Got to find some way that enough mass (or energy) leaks out (somehow) asymmetrically of the EM Drive to justify the claimed self-acceleration of its center of mass without breaking Conservation of Momentum.

Either that, or you have to couple to an external directional field.

(delete)

EDIT: I'm confused as to why putting energy "in" does not result in the same physics as letting energy "out". If the system is gaining energy from the outside, +dm/dt, why is that not the same as expelling it to the outside as -dm/dt in the opposite direction?

If you draw a boundary around the exterior boundary of the spaceship, the energy powering the EM Drive is internally produced (say by a nuclear powerplant inside the spaceship  ;) ).  The EM Drive proponents propose that there is no need of external energy coming in.  They also propose that there is no mass or energy coming out to enable the propulsion.

Something's got to give.

Otherwise it breaks Conservation of Momentum and Conservation of Energy.

Either there is enough mass (or energy) leaking out (somehow) asymmetrically of the EM Drive to justify the claimed self-acceleration of its center of mass, or you have to couple to an external directional field.
« Last Edit: 06/16/2015 04:27 PM by Rodal »

Offline rfmwguy

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I've updated my Theory on the Wiki.

http://emdrive.wiki/Todd_Desiato_(@WarpTech)%27s_Evanescent_Wave_Theory#Application_of_Theory_to_the_EmDrive

The EM Drive is intentionally designed to have asymmetrical attenuation. As such, energy is reflected from the large end to be stored at the small end as induced currents. Standing waves store energy and as such, store mass. As the EM drive charges and the Q ramps up, energy from the input source is reflected from the large end and stored in the small end on each successive reflection cycle. This energy is stored as induction currents caused by the near-field effects of evanescent waves. Due to the phase shift, the Power Factor is not zero as it is with standing waves. Therefore, work can be done to move the EM Drive. This dynamic action of storing mass-energy toward the front causes the center of mass to walk forward. The increasing pressure on the small end causes the EM Drive to accelerate forward due to the internal pressure gradient, until the pressure is equalized. Then the cycle builds again. This dynamic implies that a high Q value is not required, but rather how quickly can energy be ramped up under extreme attenuation conditions.
Todd
Got to find some way that enough mass (or energy) leaks out (somehow) asymmetrically of the EM Drive to justify the claimed self-acceleration of its center of mass without breaking Conservation of Momentum.

Either that, or you have to couple to an external directional field.

This has been my thought experiment...a point or points coupling to a natural entropic force. Surfing the wave so to speak or riding the wind. Sorry for the basic description...I cannot visualize particle or wave ejection/leakage thrusting forward nor thermal radiation of some sort. If emdrive works I'm convinced (without the math to prove it yet) that its being coupled to an elemental, natural force we have yet to measure directly. I'll leave it as an entropic force for the time being...the natural tendency for all energy and matter to disperse.

Offline sghill

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Jose,

Thanks for the explanation of "Q"! :)

One more quick sophomoric question for anyone if I may:  Could the EM Drive be creating an energy allegory to mass (for this narrow slice of frequency)?  And it's the allegorical mass that is reacting to the directional field.  In other words, E=mc2, so the more "E" we feed into the device, the more our allegorical mass grows until we can detect the space-time distortion with a laser (as Eagleworks did).  That then begs the question of whether our allegorical mass is preferential in its formation due to the frustum shape shaping field lines, resulting "falling" in a preferential direction (viewed as thrust to an external viewer).
« Last Edit: 06/16/2015 05:18 PM by sghill »
Bring the thunder Elon!

Offline Rodal

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Jose,

Thanks for the explanation of "Q"! :)

One more quick sophomoric question for anyone if I may:  Could the EM Drive be creating an energy allegory to mass (for this narrow slice of frequency)?  And it's the allegorical mass that is reacting to the directional field.  In other words, E=mc2, so the more "E" we feed into the device, the more our allegorical mass grows until we can detect the space-time distortion with a laser (as Eagleworks did).  That then begs the question of whether our allegorical mass is preferential in its formation due to the frustum shape, resulting in perceived thrust to an external viewer, when really it's just "falling" in a preferential direction.

We had physicist Marco Frasca "StrongGR" in the EM Drive thread 2, discuss his recent paper "Einstein-Maxwell equations for asymmetric resonant cavities" ( https://www.researchgate.net/publication/277334213_Einstein-Maxwell_equations_for_asymmetric_resonant_cavities ) where he shows that none of the present researchers have tested EM Drive geometries that would allow any significant coupling with General Relativity to produce the claimed measured thrust forces.  The measured thrust forces are a huge number of orders of magnitude much greater than any such interaction.  His calculations ruled out, with a very high degree of confidence, a General Relativity gravitational effect affecting the EM Drive.  However, he shows that a proper choice of the geometrical parameters of the cavity (a pointy cone) can make the gravitational effects significant for an interferometric setup. This could make possible to realize table-top experiments involving gravitational effects.

« Last Edit: 06/16/2015 05:24 PM by Rodal »

Offline deltaMass

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All of known physics is based on CoM. All of it.
Therefore, you are not going to get anywhere with known physics as an explanatory method for EmDrive.
Therefore, either EmDrive is an artifact of poor experimental technique, or new physics is required.
There is no third way.

Offline MyronQG

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All of known physics is based on CoM. All of it.
Therefore, you are not going to get anywhere with known physics as an explanatory method for EmDrive.
Therefore, either EmDrive is an artifact of poor experimental technique, or new physics is required.
There is no third way.
I wouldn't say it better.

Offline SeeShells

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I look at it this way and correct me if I'm wrong. The EM Drive could be thought of like this. You are trapped in an enclosed tank with a fire extinguisher and you turn on the fire extinguisher expecting it to move the tank, it doesn't because it's a enclosed system, but if you run up the side of the tank changing the local enclosed gravity profile of the tank, then you can move it in the direction you are running. And you haven't violated any laws just changed the local enclosed profile.
Shell

It's an interesting idea, but the flaw is the concept of an enclosed system. In moving up the tank wall you are working against the local gravity which is part of the working system. If your tank was in orbit, you could run around the inside all day and you'd get the tank spinning, but not change your orbit, as opposed to rolling across the ground, constantly applying a torque and lifting yourself against gravity.

Thanks for answering and you are very correct in classical physics there is no way, but maybe I need to take it up one notch as there is something happening.

It's not so much as it rolling the tank against local gravity on dirt I'm talking about. It's creating a small localized gravity differential on the side of the tank and a corresponding one is created on the other side. Yes and space is warped in the vicinity where I'm running (or the end of the EM Thruster in buildup of energy with Q), just a little as it will not take very much.

In my thought experiment I'm simply trying to logically define what is happening, using Occam's Razor. I asked what must be happening to get to the outside or the outside getting in? I thought being in the hypothetical tank the walls are going to protect you from the crushing gravity of a let's say black hole? Unless you were orbiting the hole and then you feel effectively 0 g, and if I'm right orbiting is acceleration (a slow spiral into the object) (Einstein said this). In orbiting you create your own localized warpage of space time and that is why we can orbit.

What else can leak out of the metal Frustum to mimic an effect like thrust, a potential to want to move to another position in spacetime?  Tunneling quantum particles normally will only travel through 3-5um of material, a problem showing up in microelectronics and maybe a boon for quantum computing but that's another story. Evanescent waves or virtual particles (like those that form at 1/3 of a wavelength of an antenna) a big maybe and if they do I think they could be also responsible for the other half of the spacetime warpage in front of the Frustum. It seems not much could escape those walls but this.

WarpTech (thanks) says that speed while relative you still need to "keep track" of your speed and this is done by your apparent mass and your apparent space timeframe. We know this is true because  a long time ago two watches were used to prove it. One stayed put while the other flew around the world and when they landed there was a difference in time. Moving in spacetime keeps track by increasing your mass and changing time, the quarks and gluons and atoms squeeze just a little more together get a little more dense and gain mass. Increase the mass and time slows down. The EM Frustum seems to match this and if someone was smart they would put a clock into a Frustum and one outside and measure after just to see if there was a time differential. I suspect a clock in the smaller end of the Frustum will beat a little slower.

I know we're not supposed to talk to much about warp drive here but this is more like a gravity drive and geez this Occam's Razor is cutting deep.

Shell

Offline WarpTech

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All of known physics is based on CoM. All of it.
Therefore, you are not going to get anywhere with known physics as an explanatory method for EmDrive.
Therefore, either EmDrive is an artifact of poor experimental technique, or new physics is required.
There is no third way.

Here's a proposal I've been contemplating, but I'm sure it will raise some controversy and I’m not sure I’ve worded it absolutely perfectly. I'm trying to convey the concept at this point, rather than the Math. It is the QM version of the Lorentz Force and gauge potentials, as applied to a frustum.

Newtonian gravity is simply the gradient of a scalar potential. We have such a scalar potential inside the frustum, it is the gradient in magnetic flux, Φ. Consider a constant azimuthal B-field circulating around the axis of the frustum. There will be less flux at the small end than at the large end. This is a "difference in potential", and as such it contributes to the Lorentz force through the Bohm-Aharanonov effect.

In this magnetic field configuration, current flows from the big end toward the small end along the walls. The current density J is increasing as it approaches the small end. Force density is increasing;

f = J x B,

The drift velocity of the electrons in the copper is accelerating;

vd = J/n*e,

Where n is the density of electrons in copper, and e is the electron's charge. For constant current, the acceleration depends on the cross sectional area, "A";

ad = (I/n*e)(1/A2)*dA/dt,

Which is negative since A is decreasing toward the front. This can be cast in the form;

φ = (q/hbar)*(Φ(small end) - Φ(big end)),

where φ is the Phase, Φ is the Magnetic flux and q is the total charge. This represents a phase shift of the electron wave functions as they accelerate. Due to this potential difference, current flowing in the walls should feel a force toward the small end. In the CM frame, the copper atoms are moving in the opposite direction and feel a force in the same direction. So the system "falls" forward, or one can think of it as the CM drags it forward, as in Frame Dragging. This is just another way in which the frustum mimics gravity.

As the energy builds up inside the frustum, the CM walks forward increasing this gradient until the frustum moves forward to compensate. At which time the CM falls backwards to begin the cycle again. Inside, the CM is oscillating back and forth, gaining mass as it moves forward, losing it as it moves backwards as it would "in an accelerated reference frame". IMO, this should cause thrust as the frustum moves to compensate it.
Todd
« Last Edit: 06/16/2015 06:21 PM by WarpTech »

Offline deltaMass

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If I understand correctly your intent to attribute cavity momentum to a field property, then the field will carry off equal and opposite momentum. So are you describing radiation reaction?

If you are, then because the system is closed, there is net zero momentum expressed externally.

You also need to account for forces that are 1000x greater than that expected of a photon rocket, and you seem intent on doing that using electromagnetism. Known physics says that this is impossible.

Offline Paul Novy

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Quote from: rfmwguy

This has been my thought experiment...a point or points coupling to a natural entropic force. Surfing the wave so to speak or riding the wind. Sorry for the basic description...I cannot visualize particle or wave ejection/leakage thrusting forward nor thermal radiation of some sort. If emdrive works I'm convinced (without the math to prove it yet) that its being coupled to an elemental, natural force we have yet to measure directly. I'll leave it as an entropic force for the time being...the natural tendency for all energy and matter to disperse.

So how do you explain life? Self organizing, becoming more and more complex, Fibonacci patterned from micro to macro scale. Apparently it is defying this mighty force.
« Last Edit: 06/16/2015 06:35 PM by Paul Novy »

Offline deltaMass

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Life does not violate thermodynamics.

Offline WarpTech

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If I understand correctly your intent to attribute cavity momentum to a field property, then the field will carry off equal and opposite momentum. So are you describing radiation reaction?

If you are, then because the system is closed, there is net zero momentum expressed externally.

You also need to account for forces that are 1000x greater than that expected of a photon rocket, and you seem intent on doing that using electromagnetism. Known physics says that this is impossible.

"Known" does not mean "understand", since I "know" that gravity can be mimicked by an EM effect, and this is not well understood by others. So this response does not surprise me.  :)

In a Newtonian gravitational field, an object falls to lower its potential energy. It loses energy and gains mass in the process. It does not eject mass to conserve momentum;

E => E/sqrt(K)
m => m*K^3/2

In what I've proposed, the frustum "falls" forward to lower it's potential energy as it gains mass. The frustum is charged by a magnetron to raise it's potential energy and input more mass. It doesn't lose mass if it gains velocity.

The "New Physics" you want is right in front of you! I'm showing you how to mimic gravity using magnetic flux as a gauge-gravity potential. This is about as NEW as it gets! Gauge potentials are simply the potential for a phase shift. The phase shift caused by magnetic flux is indistinguishable from the phase shift caused by a gravitational field, acting on the identical wave function. Most people do not understand this clearly.
Todd
« Last Edit: 06/16/2015 07:00 PM by WarpTech »

Offline Rodal

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If I understand correctly your intent to attribute cavity momentum to a field property, then the field will carry off equal and opposite momentum. So are you describing radiation reaction?

If you are, then because the system is closed, there is net zero momentum expressed externally.

You also need to account for forces that are 1000x greater than that expected of a photon rocket, and you seem intent on doing that using electromagnetism. Known physics says that this is impossible.

"Known" does not mean "understand", since I "know" that gravity can be mimicked by an EM effect, and this is not well understood by others. So this response does not surprise me.  :)

In a Newtonian gravitational field, an object falls to lower its potential energy. It loses energy and gains mass in the process. It does not eject mass to conserve momentum;

E => E/sqrt(K)
m => m*K^3/2

In what I've proposed, the frustum "falls" forward to lower it's potential energy as it gains mass. The frustum is charged by a magnetron to raise it's potential energy and input more mass. It doesn't lose mass if it gains velocity.

The "New Physics" you want is right in front of you! I'm showing you how to mimic gravity using magnetic flux as a gauge-gravity potential. This is about as NEW as it gets! Gauge potentials are simply the potential for a phase shift. The phase shift caused by magnetic flux is indistinguishable from the phase shift caused by a gravitational field, acting on the identical wave function. Most people do not understand this clearly.
Todd

There is no problem in visualizing moving an object with an external electromagnetic field, external to the object.

But in the EM Drive the electromagnetic field is inside the cavity, instead of the cavity being inside an external electromagnetic field.

The example you give is of an object falling, with  a gravity field that is all around, external to the object as well.


Offline demofsky

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Is it really correct to view an EM drive as a closed system?  For instance, as far as I know, no one has measured the external magnetic fields these things throw off.  Most experiments use copper fustrums and so they must be coupled electromagnetically to the outside world. 


Offline madsci

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Df = 0.7311 @ 24,100,700,000Hz (from their freq meter) @ TE01x as per attached

  I think it would be useful to estimate the expected thrust for the Baby Em Drive according to various models.

  To get the ball rolling, let's start with the calculation posted by TheTraveller.
  He used:
    PIn=1W
    Q=50e3
and got
    Thrust=0.244mN

   However, the power for the radar module is much smaller than 1W, probably 3-10mW.
   For example this module

   http://www.alibaba.com/product-detail/360degree-radar-24ghz-K-Band-Bistatic_60028127891.html

has the following specifications:
   Frequency Setting:   24.050~24.250 GHz
   Radiated Power (EIRP):   2.0~3.0mW
   Settling Time:     5~20μSec
   Received Signal Strength:    150~250μVp-p
   Noise:     4.0~5.0mVrms
   Supply Voltage:     4.75~5.25 VDC
   Current Consumption:     25~45mA
   Pulse Repetition Frequency:    1.8~3.0 KHz
   Pulse Width:     10~30μSec
   Operating Temperature:    -20~60C
   Weight:     2.5~4.0g

  Moreover, the Q=50e3 seems high for the cavity given its rough walls, big hole for the microwave cable, etc..
  Let's say that Q is in the range 5e3-10e3.
  Maybe other people with microwave experience can give better estimations.

  So the new data is:
   PIn=3 - 10mW
   Q=5e3 - 10e3
therefore
   Thrust=0.073uN - 0.488uN


  I assumed that the thrust scales linearly with power and Q.
  So, even in the best case the thrust is half of a micro Newton, which is very small. The NASA lab experiments were looking for thrusts of 10-50uN, if I'm not mistaken, and even they found difficult to discern the signal from the noise.
« Last Edit: 06/16/2015 07:29 PM by madsci »

Offline ElizabethGreene

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I have the following design equation for a box resonator.
L,M,N being the number of half wavelengths for the box dimensions d,b,a respectively.


Is there a similar equation for truncated cone shaped resonators?  I do not trust my ability to derive it.
Thanks.

Offline madsci

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  This is TheTraveler's model thrust prediction for the Baby EmDrive:

   PIn=3 - 10mW
   Q=5e3 - 10e3
therefore
   Thrust=0.073uN - 0.488uN

  Can someone calculate the thrust predictions given by the other models, using the same data ?

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