EM drive - predictive analysis

#40 by dustinthewind on 15 Feb, 2017 03:12
Quote from: meberbs on 03 Feb, 2017 16:34
Energy and momentum conservation show that photons thrust is the best you can do if you start with pure energy. Generating particles to emit as reaction mass consumes energy and reduces the thrust per input power. I can just look at the initial and final conditions of your claimed setup and tell that you are violating energy or momentum conservation.

This means you are making a mistake in the middle somewhere. There is plenty of room for you to post your math here, and then someone (me if I have time) can help you find your mistake.

The photon recycling thruster immediately disproves the assumption that the best thrust you can get is that of collimated light. The thrust achievable with photon recycling thrusters is larger.
#41 by dustinthewind on 15 Feb, 2017 03:37
It appears to me your on a similar subject to what I was looking into earlier. Here is a paper I wrote on the subject. It is underdeveloped as I haven't had a lot of time to work on it.

Here is one quote from the paper,

Quote
III. THEORY OF ACCELERATED LIGHT AND OTHER SOURCES
If one searches for the term “waveguide” in the book, “Theory of Photon Acceleration” by J T Mendonca2 it discussed how the eﬀective mass of a photon can change in a waveguide that approaches cutoﬀ wavelength, as well as a plasma. Another source was found discussing a change in the eﬀective mass of light in a waveguide approaching cutoﬀ wavelength titled, “Alternative perspective on photonic tunneling” by Zhi-Yong Wang1, Cai-Dong Xiong, Bing He5. It appears they show how a photon in a narrow waveguide may appear to change in mass and how it relates to evanescent waves. The author suspects how photons in the vacuum can excite electron positron (ep) pairs and those pairs when they annihilate can create photon pairs suggest that photons may them selves be low level excitations of overlapping ep pairs. If our quantum vacuum is made up of hidden ep pairs, then an acceleration of light may directly be a form of accelerating the quantum vacuum. This may parallel to locally accelerating a frame as happens when light enters a gravitational ﬁeld.

The document is attached below and I will give you the research gate link here: https://www.researchgate.net/project/Is-the-frustum-EM-Drive4-decelerating-light-for-propellantless-propulsion

It might be possible that anti-matter is negative matter running backwards in time. That is a positron is a negative energy electron running in reverse time such that it appears to have a positive charge and appears to be positive matter. When a position overlaps with a positive energy electron that runs forward in time, the time should cancel and the appearance of the positron overlapping with the electron should be that of negative energy canceling with positive energy and they should vanish into the vacuum.

However, the vacuum not being empty is full of other such pairs which never truly disappear and osculate at minimum energy (the minimum temperature of the vacuum). Upon experiencing the electric field of the two pairs annihilating these other pairs are disturbed and so a light wave is excited upon the annihilation of a positron-electron pair.

If we reverse time all that light converging on one point will excite again the formation of this e-p pair. As we can see energy is conserved upon the annihilation of the pair.

If we can accelerate light and its local frame we may be accelerating the local pairs in which most matter may be in an intricate dance with, called the vacuum.

I suspect the stretching of the wavelength of the light in the cone tip of the frustum may be changing the effective mass of the pairs, which are not fully separated (very small separation) such that they transfer different ratio's of energy to a certain side of the cavity as opposed to the other side due to differences in effective mass. This would explain why the Q of the cavity is important or with each photon reflection cycle a bit more energy is transferred to the cavity and the light should lose energy. The change in frequency of the light would represent a change in the local frame of the e-p pairs or an acceleration of them and in doing so influence the cavity.

Hopefully that isn't too confusing of an explanation.

I have been very busy unfortunately as of late, however message me if you have any specific questions.

Is the frustum EM Drive4 decelerating light for propellantless propulsion_v1.12.pdf
#42 by as58 on 15 Feb, 2017 06:35
Quote from: dustinthewind on 15 Feb, 2017 03:12
Quote from: meberbs on 03 Feb, 2017 16:34
Energy and momentum conservation show that photons thrust is the best you can do if you start with pure energy. Generating particles to emit as reaction mass consumes energy and reduces the thrust per input power. I can just look at the initial and final conditions of your claimed setup and tell that you are violating energy or momentum conservation.

This means you are making a mistake in the middle somewhere. There is plenty of room for you to post your math here, and then someone (me if I have time) can help you find your mistake.

The photon recycling thruster immediately disproves the assumption that the best thrust you can get is that of collimated light. The thrust achievable with photon recycling thrusters is larger.

Yes, and the reason for this has been explained many times. It has nothing at all to do with propellantless thrust.
#43 by sanman on 15 Feb, 2017 17:07
Quote from: as58 on 15 Feb, 2017 06:35
Quote from: dustinthewind on 15 Feb, 2017 03:12
The photon recycling thruster immediately disproves the assumption that the best thrust you can get is that of collimated light. The thrust achievable with photon recycling thrusters is larger.

Yes, and the reason for this has been explained many times. It has nothing at all to do with propellantless thrust.

You're right that the Recycling Thruster has nothing to do with the Quantum Vacuum and Propellantless Propulsion. However, it does demonstrate that Resonance can milk more juice out of photons to obtain more momentum transfer than is possible from an ordinary Photon Rocket like a flashlight-in-space.

Unlike Prof Bae's Recycling Thruster, the EMdrive concept seeks to do the Propellantless Propulsion, but it seeks to exploit the Resonance to help it do so in a meaningful way - ie. achieve a more meaningful amount of thrust than would otherwise be possible without the resonance.
#44 by dustinthewind on 16 Feb, 2017 00:23
Quote from: sanman on 15 Feb, 2017 17:07
Quote from: as58 on 15 Feb, 2017 06:35
Quote from: dustinthewind on 15 Feb, 2017 03:12
The photon recycling thruster immediately disproves the assumption that the best thrust you can get is that of collimated light. The thrust achievable with photon recycling thrusters is larger.

Yes, and the reason for this has been explained many times. It has nothing at all to do with propellantless thrust.

You're right that the Recycling Thruster has nothing to do with the Quantum Vacuum and Propellantless Propulsion. However, it does demonstrate that Resonance can milk more juice out of photons to obtain more momentum transfer than is possible from an ordinary Photon Rocket like a flashlight-in-space.

Unlike Prof Bae's Recycling Thruster, the EMdrive concept seeks to do the Propellantless Propulsion, but it seeks to exploit the Resonance to help it do so in a meaningful way - ie. achieve a more meaningful amount of thrust than would otherwise be possible without the resonance.

I think you got the point. It is about effectively siphoning the energy from a photon if possible. A large object firing off a very weak in mass projectile is a recipe for transferring very little kinetic energy to the large object. A laser firing into space would observe very little energy received as kinetic energy from such an act.

However, if the mass of a photon can change with its electric field. That is if changing its wavelength in free space changes the effective impulse of a photon. Or in other words, a photon is actually a phantom e-p pair that can change effective mass depending on separation. (non-fully formed e-p pair out of the vacuum) then by effectively changing mass maybe its possible to change effective impulse or ratio of energy transferred to one side of the cavity.

After many reflections it may be possible to more effectively drain energy from light, similar to the way a recycling photon thrust works, but where as a recycling photon thruster pushes on its other half. An object pushing off light (a closed cavity) might be accelerating the local frame of light (e-p pairs in the vacuum) inducing Doppler shifts that effectively drain energy from light to kinetic energy of the large object.

Indeed some experiments have already shown detection of changes in the impulse of light when it changes in wavelength and reflects off a mirror. Particularly in water. This seems to imply an effective change in mass of the photon, changing its ratio of energy exchanged with the mirror.
#45 by sanman on 18 Feb, 2017 02:27
Could the Rocket Bell in conventional chemical rockets provide a useful analogy?

Whether or not you have the Rocket Bell there, you are still spewing the same hot gas out of your combustion chamber.

But having the Rocket Bell there allows you to extract more useful energy from the exhaust gas than would otherwise be possible.
#46 by dustinthewind on 18 Feb, 2017 02:49
Quote from: sanman on 18 Feb, 2017 02:27
Could the Rocket Bell in conventional chemical rockets provide a useful analogy?

Whether or not you have the Rocket Bell there, you are still spewing the same hot gas out of your combustion chamber.

But having the Rocket Bell there allows you to extract more useful energy from the exhaust gas than would otherwise be possible.

My guess is just an educated guess because I haven't studied much in rocket physics. I would guess the bell shape is more to direct the propellant in a certain direction. Probably as it exits with out it the particles may scatter in all direction. What you want is collimation of the propellant, so it all travels in the opposite direction of the desired thrust.

Propellant scattering degrades the thrust. I would guess the bell helps focus this. It is similar with laser light as the light is highly collimated but laser light provides so very little thrust because of its extremely small "effective" mass compared to the mass of the ship exhausting it. With propellant the particles are much more massive with respect to the ship compared to photons. Be careful not to tell people that photons have mass. They only have "effective" mass because of the energy they possess.

Often to get more thrust, more energy is given to the exhaust so it has higher velocity, but the ratio of energy exchanged between each particle of propellant expelled and the ship remains the same, depending on their respective masses.
#47 by sanman on 18 Feb, 2017 03:31
Meh - in the end, even a Rocket Bell seems to be about extracting more energy or momentum for better performance.

The question is - do the photons bouncing around in EMdrive get used up? And if they do, then where do the skeptics think that energy goes?
#48 by aero on 18 Feb, 2017 07:01
The de-Laval nozzle or convergent-divergent nozzle (bell nozzle) is designed to provide a uniform increase in cross-sectional area as a distance from the nozzle throat, and based on the throat radius. Making the area increase linearly avoids shock waves forming in the nozzle flow. That is, internal to the nozzle, once the flow exits, well we've seen the videos showing shocks in rocket exhaust.
#49 by iRoman on 14 Mar, 2017 09:17
Quote from: cristian on 29 Jan, 2017 19:37
I want to emphasize a few points related to this issue. I will assume that the thrust experimentally observed, as related to the EM drive, is a real phenomenon, and I will try to explain it. I will mention the following interconnected effects, the dynamical Casimir effect, Unruh radiation of accelerated mirrors, and the Schwinger effect.

Law of conservation of momentum: The geometric sum of the momenta of the bodies making up the closed system remains constant for any motions and interactions of the bodies of the system. This is one of the fundamental laws of physics. If EM Drive has uncompensated force in an experiment, then is not closed system (have is interaction with the external environment). I repeat, effects are secondary and are the result of interaction with the external environment. F(EM) = 0
#50 by ppnl on 18 Mar, 2017 01:51
Quote from: cristian on 06 Feb, 2017 14:03

Note that the "battery" energy (the energy required to set up the system), is only used at stage 1 and stage 2. Stage 3 is all about the energy stored in the Coulomb fields of the nuclei of the atoms in the metal (the crystal lattice that will accelerate the positrons generated at stage 2). This is what makes the difference, and what makes this superior to a pure photonic drive.

There is energy in fields but you cannot use that energy without destroying the field. Like all energy if you use it it must go away.

In the case of an atom you may extract energy by splitting or fusing the atom. With electrons you can get energy by annihilating them with anti-electrons. In all cases you will vastly alter the particle that furnishes the energy.

There is no free lunch. If there is a source of energy and you use it then you use that source up. It is just another battery.