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#500
by
dustinthewind
on 12 May, 2021 19:58
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The apparent negative results of the Tajmar Group experiment on the EM-Drive phenomenon associated with an asymmetric cavity were analysed by Mike McCulloch and refuted.
8
Tajmar put the cavity in a metal enclosure, making it act as a horizon for Unrhu radiation, thus totally disrupting its influence on the inertias expected for the EM-Drive phenomenon to occur.
All this is explained in more detail and rigour on Mike McCulloch's Blog.
Tajmar needs to redo his test by removing the damn metal enclosure that disrupted everything.
The EM-Drive is still alive!
https://physicsfromtheedge.blogspot.com/2021/04/response-to-tajmars-new-cavity-results.htmlhttps://physicsfromtheedge.blogspot.com/2021/04/response-to-tajmars-new-cavity-results.html
I'm not quite up to date on Mikes method or concept of Unruh radiation so maybe I have something to learn here. How exactly is the unruh radiation inside an assymetric Faraday can or EM Drive supposed to push the can if it can't escape the can? If it can escape the emdrive can, how is it not supposed to escape Tajmar's Faraday cage to carry away momentum?
I take it this Unruh radiation doesn't really behave like a gravitational field in that it can't penetrate a shielded source so then what kind of field is this? I know White references virtual particles. Is this supposed to be a virtual particle field? How does it escape the em drive can and not a Faraday cage?
I am also curious in that he predicts galaxy rotation, attributed to dark matter halos, but also just recently this dark matter halo was attributed to gravitomagnetic possibly. It would need to be investigated how these predictions differ from one another.
I know one way a dark matter halo would differ from gravitomagnetism is that one is a magnetic effect and the other is not. An object moving against the flow of gravitomagnetism, with opposite angular velocity would experience a repulsive effect, whereas with a dark-matter Halo it would still experience an attractive effect. Something to look for between the collision of 2 galaxies with appropriate spin. I am curious of mikes prediction and how he would define this Unruh radiation.
edit: ok I have something here that indicates Unruh radiation is a lot like hawking radiation in which they observe it in which either space time is rotated or an objects is rotated with respect to its local space time via the equivalence principle. I would suggest this has a lot to do with the radiation emitted during some experiments with the dynamical Casimir effect as well.
I am still at a loss how this radiation is supposed to escape the em drive but not a Faraday cage. I would assume there may be a connection to generating waves of such radiation and generating high frequency gravitational waves and the radiation is emitted as a result of the object's vector rotating its space vector into the time vector where observation of such radiation becomes real and reflecting such radiation emits it for real observation. Maybe similar to how moving through a magnetic field induces a real observation of a dipole electric field in which the object really reacts to such a field as opposed to an object not moving through such a magnetic field does not observe or react to such a dipole electric field . Dipole electric fields dropping off with distance cubed as do magnetic fields and observation being velocity dependent and related to space time, defined as such because magnetic fields would not exist if not for relativistic effects.
So still at a loss how the radiation is escaping the emdrive can and not a Faraday cage.
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#501
by
Mark7777777
on 15 May, 2021 01:36
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The apparent negative results of the Tajmar Group experiment on the EM-Drive phenomenon associated with an asymmetric cavity were analysed by Mike McCulloch and refuted.
8
Tajmar put the cavity in a metal enclosure, making it act as a horizon for Unrhu radiation, thus totally disrupting its influence on the inertias expected for the EM-Drive phenomenon to occur.
All this is explained in more detail and rigour on Mike McCulloch's Blog.
Tajmar needs to redo his test by removing the damn metal enclosure that disrupted everything.
The EM-Drive is still alive!
https://physicsfromtheedge.blogspot.com/2021/04/response-to-tajmars-new-cavity-results.htmlhttps://physicsfromtheedge.blogspot.com/2021/04/response-to-tajmars-new-cavity-results.html
I'm not quite up to date on Mikes method or concept of Unruh radiation so maybe I have something to learn here. How exactly is the unruh radiation inside an assymetric Faraday can or EM Drive supposed to push the can if it can't escape the can? If it can escape the emdrive can, how is it not supposed to escape Tajmar's Faraday cage to carry away momentum?
I take it this Unruh radiation doesn't really behave like a gravitational field in that it can't penetrate a shielded source so then what kind of field is this? I know White references virtual particles. Is this supposed to be a virtual particle field? How does it escape the em drive can and not a Faraday cage?
I am also curious in that he predicts galaxy rotation, attributed to dark matter halos, but also just recently this dark matter halo was attributed to gravitomagnetic possibly. It would need to be investigated how these predictions differ from one another.
I know one way a dark matter halo would differ from gravitomagnetism is that one is a magnetic effect and the other is not. An object moving against the flow of gravitomagnetism, with opposite angular velocity would experience a repulsive effect, whereas with a dark-matter Halo it would still experience an attractive effect. Something to look for between the collision of 2 galaxies with appropriate spin. I am curious of mikes prediction and how he would define this Unruh radiation.
edit: ok I have something here that indicates Unruh radiation is a lot like hawking radiation in which they observe it in which either space time is rotated or an objects is rotated with respect to its local space time via the equivalence principle. I would suggest this has a lot to do with the radiation emitted during some experiments with the dynamical Casimir effect as well.
I am still at a loss how this radiation is supposed to escape the em drive but not a Faraday cage. I would assume there may be a connection to generating waves of such radiation and generating high frequency gravitational waves and the radiation is emitted as a result of the object's vector rotating its space vector into the time vector where observation of such radiation becomes real and reflecting such radiation emits it for real observation. Maybe similar to how moving through a magnetic field induces a real observation of a dipole electric field in which the object really reacts to such a field as opposed to an object not moving through such a magnetic field does not observe or react to such a dipole electric field . Dipole electric fields dropping off with distance cubed as do magnetic fields and observation being velocity dependent and related to space time, defined as such because magnetic fields would not exist if not for relativistic effects.
So still at a loss how the radiation is escaping the emdrive can and not a Faraday cage.
I didn’t study uni physics but it may be something to do with the answer of “b” given here:
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#502
by
dustinthewind
on 18 May, 2021 20:26
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The apparent negative results of the Tajmar Group experiment on the EM-Drive phenomenon associated with an asymmetric cavity were analysed by Mike McCulloch and refuted.
8
Tajmar put the cavity in a metal enclosure, making it act as a horizon for Unrhu radiation, thus totally disrupting its influence on the inertias expected for the EM-Drive phenomenon to occur.
All this is explained in more detail and rigour on Mike McCulloch's Blog.
Tajmar needs to redo his test by removing the damn metal enclosure that disrupted everything.
The EM-Drive is still alive!
https://physicsfromtheedge.blogspot.com/2021/04/response-to-tajmars-new-cavity-results.htmlhttps://physicsfromtheedge.blogspot.com/2021/04/response-to-tajmars-new-cavity-results.html
I'm not quite up to date on Mikes method or concept of Unruh radiation so maybe I have something to learn here. How exactly is the unruh radiation inside an assymetric Faraday can or EM Drive supposed to push the can if it can't escape the can? If it can escape the emdrive can, how is it not supposed to escape Tajmar's Faraday cage to carry away momentum?
I take it this Unruh radiation doesn't really behave like a gravitational field in that it can't penetrate a shielded source so then what kind of field is this? I know White references virtual particles. Is this supposed to be a virtual particle field? How does it escape the em drive can and not a Faraday cage?
I am also curious in that he predicts galaxy rotation, attributed to dark matter halos, but also just recently this dark matter halo was attributed to gravitomagnetic possibly. It would need to be investigated how these predictions differ from one another.
I know one way a dark matter halo would differ from gravitomagnetism is that one is a magnetic effect and the other is not. An object moving against the flow of gravitomagnetism, with opposite angular velocity would experience a repulsive effect, whereas with a dark-matter Halo it would still experience an attractive effect. Something to look for between the collision of 2 galaxies with appropriate spin. I am curious of mikes prediction and how he would define this Unruh radiation.
edit: ok I have something here that indicates Unruh radiation is a lot like hawking radiation in which they observe it in which either space time is rotated or an objects is rotated with respect to its local space time via the equivalence principle. I would suggest this has a lot to do with the radiation emitted during some experiments with the dynamical Casimir effect as well.
I am still at a loss how this radiation is supposed to escape the em drive but not a Faraday cage. I would assume there may be a connection to generating waves of such radiation and generating high frequency gravitational waves and the radiation is emitted as a result of the object's vector rotating its space vector into the time vector where observation of such radiation becomes real and reflecting such radiation emits it for real observation. Maybe similar to how moving through a magnetic field induces a real observation of a dipole electric field in which the object really reacts to such a field as opposed to an object not moving through such a magnetic field does not observe or react to such a dipole electric field . Dipole electric fields dropping off with distance cubed as do magnetic fields and observation being velocity dependent and related to space time, defined as such because magnetic fields would not exist if not for relativistic effects.
So still at a loss how the radiation is escaping the emdrive can and not a Faraday cage.
I didn’t study uni physics but it may be something to do with the answer of “b” given here:
Thanks, I'm guessing it is likely related to the dynamical Casimir effect. White was proposing also that virtual particles were involved. The unruh effect is also linked to virtual particles. In an accelerated frame it seems the accelerated observer perceives radiation coming from the space that is accelerating with respect to them or they are accelerating with respect to, equivalence effect. I think they can model these virtual particles as flowing at different velocities in different regions of space, influenced by a gravitational field. An accelerated frame over space has different rotation with respect to neighboring regions over space. This seems to effect the rate of time also in neighboring regions. Ultimately it is probably linked to space time and some quantum interpretation of it but that field of research needs a lot of development, at least that I am aware of, linking general relativity and the quantum vacuum. My guess is if correct a quantum interpretation should reduce to general relativity. I know they take the Casimir effect to see barriers from reflective surfaces but gravity naturally penetrates. Radiation reflects but magnetic fields penetrate, charge inside a metal sphere also penetrates the sphere so maybe a link there.. There is an intricate link with effects related to gravity and the hawking effect where we are seeing an unerving connection between the two, gravity and the quantum vacuum. There needs to be some clarity why he thinks the em cavity could push against something that escapes but that something can't escape a Faraday cage though.
Maybe in a gravitomagnetic field there is a flow of such virtual particles
Edit:
I think this is related and shows how when you change perspective from a coordinate speed of light to a constant speed of light you perceive the vacuum as having radiation pressure or a gradient. Basically shifting Viewpoint from a non-local Observer to a local Observer. What is important is that there is an equivalence effect of being in a gravitational field with rotated space or an accelerated observer and how they perceive space time here.
The Electromagnetic Zero-point Field and the Flat Polarizable Vacuum Representation
JT Desiato, CR Storti
So maybe like the unruh effect as virtual radiation/virtual particles?
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#503
by
flux_capacitor
on 24 May, 2021 18:05
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dustinthewind, when you put an asymmetrical object within a symmetrical Faraday cage, the Faraday cage is no more symmetrical from the point of view of quantized inertia. It becomes asymmetrical. Think like a boolean subtracting operation where the volume of the Faraday cage is subtracted by the volume of the frustum (case
c below):
Figure (a) shows an incomplete understanding of quantised inertia. The Unruh waves seen by a highly-accelerated object (photon, black circle) in an asymmetric cavity are more energetic (hotter) at the wide end (red), and cooler at the narrow end (blue), so an internal object is pushed left, but the cavity is not: any forces are only internal. A better picture is (b): the Unruh waves seen by the accelerated object also exist outside the cavity which is partially transparent to them and therefore the cavity ‘falls down’ the Unruh gradient. This is how quantised inertia predicts thrust. In case (c), representing Tajmar’s copper or silver cavity tests, the cavity is inside a metal box so there will be a push (see colours) between the cavity & box but friction stops movement. QI predicts that the combined cavity+box must show no or much less thrust: there’s no background gradient.
Source:
https://physicsfromtheedge.blogspot.com/2021/04/response-to-tajmars-new-cavity-results.html
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#504
by
dustinthewind
on 25 May, 2021 15:32
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dustinthewind, when you put an asymmetrical object within a symmetrical Faraday cage, the Faraday cage is no more symmetrical from the point of view of quantized inertia. It becomes asymmetrical. Think like a boolean subtracting operation where the volume of the Faraday cage is subtracted by the volume of the frustum (case c below):
Figure (a) shows an incomplete understanding of quantised inertia. The Unruh waves seen by a highly-accelerated object (photon, black circle) in an asymmetric cavity are more energetic (hotter) at the wide end (red), and cooler at the narrow end (blue), so an internal object is pushed left, but the cavity is not: any forces are only internal. A better picture is (b): the Unruh waves seen by the accelerated object also exist outside the cavity which is partially transparent to them and therefore the cavity ‘falls down’ the Unruh gradient. This is how quantised inertia predicts thrust. In case (c), representing Tajmar’s copper or silver cavity tests, the cavity is inside a metal box so there will be a push (see colours) between the cavity & box but friction stops movement. QI predicts that the combined cavity+box must show no or much less thrust: there’s no background gradient.
Source: https://physicsfromtheedge.blogspot.com/2021/04/response-to-tajmars-new-cavity-results.html
Ok, so there is something that can escape the cavity via the induction of some type of semi virtual radiation which sees the cavity as semi transparent. I am guessing this would have to be some 2ndary interaction of accelerated electrons inside the cavity interacting with photons or real radiation inside the cavity which push harder at one end of the cavity but push lighter at the other, generating some type of
edit: unidirectional semi virtual radiation which escapes the cavity.
Here is the problem. There shouldn't be nearly as much radiation outside the cavity as there is inside the cavity. While the space between the Faraday cage and the cavity is also assymetrical there aren't the same levels of real radiation so there shouldn't be any highly accelerated objects in that space that I am aware of.
Let's say that semi virtual radiation is escaping the semitransparent cavity, how is the Faraday cage not semitransparent? How is this semi virtual radiation being generated between the cavity and the Faraday cage for an equal and opposite push?
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#505
by
Alex_O
on 28 May, 2021 19:59
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dustinthewind, when you put an asymmetrical object within a symmetrical Faraday cage, the Faraday cage is no more symmetrical from the point of view of quantized inertia. It becomes asymmetrical. Think like a boolean subtracting operation where the volume of the Faraday cage is subtracted by the volume of the frustum (case c below):
Figure (a) shows an incomplete understanding of quantised inertia. The Unruh waves seen by a highly-accelerated object (photon, black circle) in an asymmetric cavity are more energetic (hotter) at the wide end (red), and cooler at the narrow end (blue), so an internal object is pushed left, but the cavity is not: any forces are only internal. A better picture is (b): the Unruh waves seen by the accelerated object also exist outside the cavity which is partially transparent to them and therefore the cavity ‘falls down’ the Unruh gradient. This is how quantised inertia predicts thrust. In case (c), representing Tajmar’s copper or silver cavity tests, the cavity is inside a metal box so there will be a push (see colours) between the cavity & box but friction stops movement. QI predicts that the combined cavity+box must show no or much less thrust: there’s no background gradient.
Source: https://physicsfromtheedge.blogspot.com/2021/04/response-to-tajmars-new-cavity-results.html
Ok, so there is something that can escape the cavity via the induction of some type of semi virtual radiation which sees the cavity as semi transparent. I am guessing this would have to be some 2ndary interaction of accelerated electrons inside the cavity interacting with photons or real radiation inside the cavity which push harder at one end of the cavity but push lighter at the other, generating some type of edit: unidirectional semi virtual radiation which escapes the cavity.
Here is the problem. There shouldn't be nearly as much radiation outside the cavity as there is inside the cavity. While the space between the Faraday cage and the cavity is also assymetrical there aren't the same levels of real radiation so there shouldn't be any highly accelerated objects in that space that I am aware of.
Let's say that semi virtual radiation is escaping the semitransparent cavity, how is the Faraday cage not semitransparent? How is this semi virtual radiation being generated between the cavity and the Faraday cage for an equal and opposite push?
Let's say that semi virtual radiation is escaping the semitransparent cavity, how is the Faraday cage not semitransparent? How is this semi virtual radiation being generated between the cavity and the Faraday cage for an equal and opposite push?Take a look at the
tutorial model from COMSOL. Two optical waveguides were placed at a distance of about 10
-6 meters.
The tutorial discusses near-field physics in a microscopic volume.
https://www.comsol.ru/model/download/841301/models.woptics.directional_coupler.pdfLight that propagates through a dielectric waveguide has most of the power concentrated
within the central core of the waveguide. Outside the waveguide core, in the cladding, the
electric field decays exponentially with the distance from the core. However, if you put
another waveguide core close to the first waveguide (see Figure 1), that second waveguide
perturbs the mode of the first waveguide (and vice versa). Thus, instead of having two
modes with the same effective index, one localized in the first waveguide and the second
mode in the second waveguide, the modes and their respective effective indices split and
you get a symmetric supermode (see Figure 2 and Figure 4 below), with an effective index
that is slightly larger than the effective index of the unperturbed waveguide mode, and an
antisymmetric supermode (see Figure 3 and Figure 5), with an effective index that is
slightly lower than the effective index of the unperturbed waveguide mode.
The details are not important, from an engineering point of view, for solving the problems of space flights without the release of reactive mass, you need to find some suitable physical effect in the already known physics. These can be different physical effects. A case study from the COMSOL shows that when discussing Faraday cages and so on (Unruh waves), one should look for
good ideas in physics in the near field.
And yes, it is very likely that the thick walls of the vacuum chamber can greatly affect the subtle phenomena in the physics of the near zone, completely change the distribution of the Unruh wave flows in the system.
Where are Unruh waves created? In the skin layer, the thickness for optical waveguides is on the order of less than a micrometer? Then the wall thickness of the vacuum chamber exceeds this by at least 5 orders of magnitude.
Waveguide wall structure and chemical composition can also make a big difference.
For example:
http://journals.ioffe.ru/articles/viewPDF/6923It is shown that to create an efficient waveguide, it is necessary to use layers of the n-AlxGa1 - xAs solid solution with x <0.45 at an electron concentration of N> 5 × 1018 cm - 3 and layers of the p-AlxGa1 - xAs solid solution of any composition at a hole concentration of P ≥ 3 1019 cm - 3. In such a waveguide, the phase matching of the “initial” waves and the “difference”
waves can be achieved due to the anomalous dispersion of the refractive index of GaAs near the transverse phonon energy hωTO = 33.25 meV [8]
.
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#506
by
dustinthewind
on 30 May, 2021 17:52
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...
Regarding the induction to a nearby waveguide. This has to do with the exponentially decaying field which in a dielectric containing the radiation allows the radiation to penetrate and even exist a bit outside the guide so that if another guide is brought close some of that radiation in the waveguide can tunnel to the other waveguide by order of the remaining amplitude existing from the exponentially decaying imaginary wave of its near field.
For a metal that skin depth is much smaller and depending on the metal thickness that wave may never even exist outside the metal for total internal reflection and containment inside the metal waveguide.
If radiation was being induced to escape the cavity it should be able to be measured inside the Faraday cage and the power stored in the Faraday cage emdrive gap could be estimated. I am guessing this should not be large with respect to what is stored in the emdrive cavity.
The virtual radiation is a factor of rotated space time one observes from either general relativity via hawking radiation where local space time is highly rotated or via an equivalence effect from one undergoing acceleration. It might be suggested that undergoing such an acceleration induces such radiation from space time and is the source of radiation generated from the dynamical Casimir effect.
edit:Also seeThe Electromagnetic Zero-point Field and the Flat Polarizable Vacuum Representation
JT Desiato, CR Storti
Where from the point of view of a constant speed of light [not a coordinate speed of light] the vacuum acquires a changing gradient in a gravitational field.An escaping wave would have a local rotation and a change in potential in which accompanying it is a wave of excited virtual particles. Emiting such a wave would require energy transfer between space time and some accelerated mechanism.
To enhance interaction with virtual particles one might introduce electric and magnetic fields. Something that occurs around stars which seem to have an effect on local light which changes the local space time index of refraction. Podkletnov was using very large magnetic and electric fields when he induced his charge acceleration on his capacitors which induced his unusual gravity impulse wave. One might wonder if there is a connection there to enhancing interaction with local space time. Such a wave escaping should allow what appears to be virtual radiation to escape. Basically space time manipulation.
Something that resembles a lot the measured unruh and dynamical Casimir effect, or the equivalence effect of hawking radiation to an accelerated observer, Podkletnov's experiment, and the mach/woodward effect. None of this guarantees the emdrive is actually achieving any of this but as required by the woodward effect it does have a possible assymetry of charge acceleration inside
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#507
by
TheTraveller
on 18 Jun, 2021 23:43
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At IAC 2021 Roger Shawyer will present a paper on his cryo superconducting CubeSat EmDrive with a 12.3N/kWe specific thrust.
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#508
by
sghill
on 20 Jun, 2021 08:13
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Pardon me for asking, but wouldn't a super conducting em-drive cubesat effectively be a big floating electro-magnet?
If so, in orbit, it would immediately act like a compass, align itself with the Earth's magnetic field, and start rotating as the cube sat travels around the planet (and also relative to the Sun's magnetic field lines).
Just turning the thing on would show immediate motion, as it oriented itself with the field lines,, but that has nothing to do with thrust....
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#509
by
dustinthewind
on 21 Jun, 2021 17:38
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Pardon me for asking, but wouldn't a super conducting em-drive cubesat effectively be a big floating electro-magnet?
If so, in orbit, it would immediately act like a compass, align itself with the Earth's magnetic field, and start rotating as the cube sat travels around the planet (and also relative to the Sun's magnetic field lines).
Just turning the thing on would show immediate motion, as it oriented itself with the field lines,, but that has nothing to do with thrust....
Something interesting to note about the superconductors is that they exclude the magnetic field except the field lines they allow to pass through the vortices when the superconductivity kicks in so they lock into the magnetic field. You have ever seen those superconductor race tracks? They follow the track of constant magnetic field but resist moving to a region where there would be a change in the magnetic field so it hovers above the track and won't fall off. Due to assymetry in earths magnetic field it would be an interesting way to lock a satellite into position but energy would be required to keep it superconducting and cool.
I think he is interested in the superconducting properties because of the increase in quality of the cavity. It increases radiation reflectivity, minimizing losses so more cycles of energy before the energy is lost to heat. If some small percentage energy were being converted per cycle then increasing the cycles allows more energy to be converted. This happens in the combustion engine or nasa recycled photon thruster and other various methods of converting energy. This is why the desiel engine is inherently more effecient than gasoline so the concept of increasing cavity quality is universal to converting energy (i think we as humanity have still yet to truly take advantage of this). 2 black holes orbiting also complete cycles and convert energy per cycle to space time energy waves "gravity waves" losing kinetic energy which is so massive it has mass equivalent and they say they throw off so many solar masses of energy falling to a lower potential energy state. Notice they effectively throw off something into space time which lowers their potential so what they throw off should have a Higher potential than the local space time as it carries it off. If you dig a deeper hole you have a pile of dirt above the hole, dirt conserved, energy conserved and the heart of conservation probably coming from the vacuum itself.
https://en.m.wikipedia.org/wiki/No-hiding_theoremAlso same as highly energetic sound waves carrying off thermally excited energy actually have buoyancy or effective negative mass with respect to the local air via their positive thermal energy. So negative mass from positive energy. Think of a thermally excited quantum vacuum and its relation of space time potential, and coordinate speed of light, time, and radioactive decay. Anyways an interesting thought about magnets in space, though superconductors are a bit different than normal magnets but yes there should be some interaction with the earths magnetic flux tubes passing through the superconductors when it gains superconductivity.
Maintaining superconductivity would cost power lowering newton's per watt. I think we are all still expecting a demonstration. Hang it from a really long string with battery in an insulated clear bubble and let her rip. Measure the angle of deflection. Show us the change in wavelength of the light inside @TheTraveler.
Maybe use antiviberation tech to hang the string so no wobble. Long tall room with no air currents. Maybe use laser perpendicular to the cavity to measure change in angle or dual mirrors to amplify angle change.
Could even drop it from known angle and measure damping then factor in a known impulse thrust at pendulums resonant frequency to get theoretical max amplitude to amplify angle of pendulum displacement. Doesnt sound like that small of a thrust though.
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#510
by
WarpTech
on 06 Aug, 2021 00:45
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...
edit:Also see
The Electromagnetic Zero-point Field and the Flat Polarizable Vacuum Representation
JT Desiato, CR Storti
Where from the point of view of a constant speed of light [not a coordinate speed of light] the vacuum acquires a changing gradient in a gravitational field.
...
That is a VERY old paper. The Engineering Model has come a long way since then. This is the JBIS published paper on warp drive:
linkThis is the latest paper on the Model:
linkHere are my latest research presentations from APEC:
Slide presentations are found on Researchgate.net.
Enjoy!
[zubenelgenubi: Very long url's must be shortened, or they will destroy the automatic formatting. Suggestion: bracket "link" or other text with the Insert Hyperlink button above.]
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#511
by
davamanra
on 06 Aug, 2021 02:14
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I can see how this "drive" could work in an atmosphere. This conical shape could focus the microwaves and cause air molecules to vibrate outside of the cone, creating a little friction and thus expansion and forming "thrust." This "thrust" would be finite as soon as the aero dynamic pressures on the other side equalized. A lot of energy used, but a miniscule amount actual "thrust". A bass speaker would yield much better results!
Now take this thing into space where there is no atmosphere to interact with, and all you have is a floating drum that can pop popcorn inside itself quickly, but will go absolutely nowhere, just like the bass speaker analogy.
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#512
by
edzieba
on 06 Aug, 2021 10:11
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Now take this thing into space where there is no atmosphere to interact with, and all you have is a floating drum that can pop popcorn inside itself quickly, but will go absolutely nowhere, just like the bass speaker analogy.
Minor nit: if the emission is asymmetric, there would be a small amount of thrust from photon emission. It'd just be a remarkably inefficient photon drive, even for photon drives!
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#513
by
davamanra
on 06 Aug, 2021 12:04
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Now take this thing into space where there is no atmosphere to interact with, and all you have is a floating drum that can pop popcorn inside itself quickly, but will go absolutely nowhere, just like the bass speaker analogy.
Minor nit: if the emission is asymmetric, there would be a small amount of thrust from photon emission. It'd just be a remarkably inefficient photon drive, even for photon drives!
If that is the case, then you might as well go with a device that shoots lasers out the back and use that for thrust.
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#514
by
edzieba
on 06 Aug, 2021 13:53
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If your reactionless drive can't beat a lightbulb next to a parabolic mirror, it's not going to be of much practical use.
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#515
by
axavier
on 26 Oct, 2021 10:40
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Hi everyone,
I work as a technologist in the Brazilian space agency, but as a physicist, I have been interested in the issue and debate of the EMdrive in my spare time.
I believe a deeper treatment of this system from the point of view of physics is still lacking, which prevents the proper understanding of the many experimental results obtained so far. Much has been said and written about this problem, but to me, classical physics provides both a starting point of analysis and a good answer.
So, I think people here will be interested in the recent pre-print: "The law of momentum conservation in free microwave cavities containing coherent radiation" (available here:
https://www.researchgate.net/publication/352209473_The_law_of_momentum_conservation_in_free_microwave_cavities_containing_coherent_radiation or through Arxiv.org),
where I do an in-depth analysis ( using classical electrodynamics ) of the amount of EM momentum (stored) in a free and closed microwave cavity of cylindrical symmetry.
The approach considers the cavity as an electromechanical system in which the mechanical momentum (manifested in the mechanical subsystem) can be exchanged with the momentum stored in the fields (the electromagnetic subsystem) so that the total momentum is conserved. Moreover, any field momentum stored in the EM mode can be converted into mechanical motion, provided the EM center of energy doesn't coincide with the original center of mass.
There is a mechanical displacement (in relation to the center of energy of the system) when the cavity is fed with EM energy in the so-called transient phase. Thus, it is true that some displacement (transient motion) is expected for such a closed system, as demanded by momentum conservation (contrary to what has been said).
Anyway, the predicted displacement is very small and the corresponding 'thrust' is too feeble to be observed in experiments.
Maybe it could be enhanced in the future - or fully demonstrated by a suitable change in the experimental arrangement.
Regards,
Ademir Xavier
https://www.researchgate.net/profile/Ademir_Xavier
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#516
by
Alex_O
on 30 Oct, 2021 09:16
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At IAC 2021 Roger Shawyer will present a paper on his cryo superconducting CubeSat EmDrive with a 12.3N/kWe specific thrust.
Hi TT. Any new information on Shawyer's report?
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#517
by
TheTraveller
on 03 Nov, 2021 13:31
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EmDrive update from Roger, where he comments
"I have attached the two EmDrive papers for the recent IAC-21 conference in Dubai. I didn’t go myself due to Covid restrictions, but links to the two video lectures I gave are now on our emdrive.com website.
I think you might find the background to EmDrive in the Solar Power Satellite paper particularly interesting. Now that the cabinet papers, referenced in the paper, have been declassified, the politics behind the original instruction to us to “think the unthinkable” are now clear. EmDrive has been known about in both the US and the UK for 46 years!"
And 2 papers as attached
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#518
by
edzieba
on 04 Nov, 2021 07:52
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EmDrive has been known about in both the US and the UK for 46 years!"
I'm not sure if "we have been unable to produce any independently verifiable evidence that any effect exists for nearly half a century" is really what Roger realised he was saying.
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#519
by
D_Dom
on 04 Nov, 2021 16:05
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Contributors from a peer reviewed version of the IAC 2014 paper available on his emdrive.com website.
References
[1] R.J. Shawyer, Microwave propulsion – progress in the EmDrive
programme SPR Ltd UK IAC-08-C4.4.7, Glasgow, 2008.
[2] Juan Yang, etal., Prediction and Experimental Measurement of the
Electromagnetic Thrust Generated by Microwave Thruster System
NWPU Xi'an China Chinese Physical Society and IOP PublishingLtd.,
2013.
[3] D. Brady, etal., Anomalous thrust production from an RF test device
measured on a low thrust torsion pendulum. NASA US AIAA Joint
Propulsion Conference, Cleveland, 2014.
[4] G.P. Fetta, Experimental and numerical results on a superconducting
prototype of a new thruster technology which requires no on-board
propellant to generate thrust. Cannae LLC US AIAA Joint Propulsion
Conference, Cleveland, 2014.
[5] R.J. Shawyer, TheEmDrive – a new satellite propulsion technology
SPR Ltd UK 2nd Conference on disruptive technology in space
activities, Toulouse, 2010.
R. Shawyer/ActaAstronautica116(2015)166–174 167
Not sure where you place the bar for "independently verifiable evidence". I would like to see results from a 12U cubesat experiment as described. Certainly not holding my breath...
