Author Topic: Propellantless Field Propulsion and application  (Read 678826 times)

Offline Star-Drive

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Re: Propellantless Field Propulsion and application
« Reply #640 on: 10/08/2009 06:46 PM »
Kkattula:

The interaction between the power generation and propulsion functions could end up being a MAJOR show stopper for this dual use approach, especially in regards to the WB electron flux since they are so light weight in comparison to the He4 ions.  However, once we've established that the WB-XX fusion reactors have met our power generation expectations, and that the M-E is a real propulsion technology to be pursued, then we should perform a detailed analysis of the interactions between the two subsystems to see if there is a happy operational middle ground where both of these subsystems can perform their intended functions without too many comprises for either.  That point is not now, but it is still a future possibility. 
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Offline mlorrey

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Re: Propellantless Field Propulsion and application
« Reply #641 on: 10/09/2009 01:30 AM »
Kkattula:

The interaction between the power generation and propulsion functions could end up being a MAJOR show stopper for this dual use approach, especially in regards to the WB electron flux since they are so light weight in comparison to the He4 ions.  However, once we've established that the WB-XX fusion reactors have met our power generation expectations, and that the M-E is a real propulsion technology to be pursued, then we should perform a detailed analysis of the interactions between the two subsystems to see if there is a happy operational middle ground where both of these subsystems can perform their intended functions without too many comprises for either.  That point is not now, but it is still a future possibility. 

Yes, if the electrons drop energy in synchrotron radiation when you are trying to generate thrust, you could see a lot of thermalization effects, brehmstrahlung, etc which one wants to minimize in a fuzor, so you may need to have two completely different units, one powering the other.
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Offline Star-Drive

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Re: Propellantless Field Propulsion and application
« Reply #642 on: 10/09/2009 12:08 PM »
Kkattula:

The interaction between the power generation and propulsion functions could end up being a MAJOR show stopper for this dual use approach, especially in regards to the WB electron flux since they are so light weight in comparison to the He4 ions.  However, once we've established that the WB-XX fusion reactors have met our power generation expectations, and that the M-E is a real propulsion technology to be pursued, then we should perform a detailed analysis of the interactions between the two subsystems to see if there is a happy operational middle ground where both of these subsystems can perform their intended functions without too many comprises for either.  That point is not now, but it is still a future possibility. 

Yes, if the electrons drop energy in synchrotron radiation when you are trying to generate thrust, you could see a lot of thermalization effects, brehmstrahlung, etc which one wants to minimize in a fuzor, so you may need to have two completely different units, one powering the other.

Mike:

Accepted.  Dr. Neble has to show us that the WB-8 & 8.1 work as advertised and the M-E team needs to conclusively demonstrate that the M-E is real and engineerable into large scale space drives.  If and when those two gates are successfully navigated, we perform a trade study on merging their two functions into one light weight reactor/drive unit.  If it turns out that this is not possible due to the technical issues discussed and any other issues found along the way, we optimize a two major subsystem M-E space drive that also provides power to the rest of the ship loads.   
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Offline isa_guy

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Re: Propellantless Field Propulsion and application
« Reply #643 on: 10/09/2009 09:07 PM »
 http://www.physorg.com/news174293159.html , interesting dont you think so  ;)?

Offline mlorrey

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Re: Propellantless Field Propulsion and application
« Reply #644 on: 10/10/2009 01:38 AM »
http://www.physorg.com/news174293159.html , interesting dont you think so  ;)?

Its an interesting theory however some of Hilbert's predictions have not held up to experiment so I am doubtful that this is going to hold long term.
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Offline Lampyridae

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Re: Propellantless Field Propulsion and application
« Reply #645 on: 10/13/2009 08:25 AM »
Trouble is, electrons don't mass a lot and you won't get a lot of thrust...

Well that depends on how many electrons you are handling plus the mass differential between high speed and low speed sides. If the solid capacitors dielectric atoms can only be varied in mass by 0.001%, and you can instead move 1000 electrons with a mass variance of 50% as they go from .1 c to .999 c from one side of the chamber to the other, and an electron is 0.0005 AMU at rest (thus becoming 0.001 AMU at .999c) then 1000 electrons exhibit a mass variance of 1 AMU per cycle.

Because you can move electrons much faster than ions, then you should be able to achieve MUCH higher cycle frequencies with the electrons in the chamber than you could with ions in a dielectric. As the charts that Paul has posted here indicate, higher the frequency, the higher the efficiency and higher the thrust.

Pulsed-lasers driving electrons with Coulomb explosions would do the trick then. Blast them off a plasma foil, shooting along at ~0.9c, but how do you slow them down? These are pactically cosmic rays now.
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Offline 93143

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Re: Propellantless Field Propulsion and application
« Reply #646 on: 10/13/2009 08:34 AM »
An electron at 0.9c isn't all that energetic.  About 660 kV should do the trick...

Offline khallow

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Re: Propellantless Field Propulsion and application
« Reply #647 on: 10/13/2009 04:09 PM »
One thing neglected in this talk of using electron propulsion is how do you keep the vehicle more or less neutrally charged? You can either just let the vehicle collide with electrons from the plasma (solar wind or interstellar medium) it travels through (this both losses some degree of energy to the collisions and reduces to a minor degree the energy of the electrons in your exhaust stream), or you can add positive charged ions to your exhaust stream to make it neutrally charged. The latter basically reduces the problem to existing and near future electric propulsion systems.
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Offline 93143

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Re: Propellantless Field Propulsion and application
« Reply #648 on: 10/13/2009 06:02 PM »
One thing neglected in this talk of using electron propulsion is how do you keep the vehicle more or less neutrally charged?

...we're not talking about ejecting the electrons.  We're talking about oscillating them in a closed plasma trap in order to leverage the Mach effect.  Take a look at the thread title...

Offline khallow

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Re: Propellantless Field Propulsion and application
« Reply #649 on: 10/14/2009 05:14 AM »
I'm sorry about that. I was wondering what this had to do with the thread. Figured it was some comparison with electric propulsion that drifted a bit.

Glancing through the previous posts, I must admit that I don't like the use of electrons in a plasma. The problem is synchrotron radiation. If you're bouncing electrons in a chamber at a significant fraction of the speed of light, you are generating a lot of photons (not sure what their frequency would be) each time you bend the path of the electron. Maybe that could be used to  transfer energy to another plasma chamber.

How about some sort of lasing mechanism? Pump energy in to a crystal lattice of atoms, pushing the electrons to a higher energy state, on one side of the centrifuge and discharge on the other side. You might even be able to recycle most of the energy involved (excluding of course that expended on net thrust). It doesn't have the raw energy of relativistic electrons, but the energy density might be better.

I wonder if there may even be a way to do this with the nuclei themselves. That is, take a nucleus in the ground state, excite it to a nuclear isomer state and then decay. Glancing around, it appears a better way might be to find a nuclear isomer that decays mostly by beta (electron) decay rather than via gamma ray photons. Perhaps one could even reliably pump that electron in and out of the nucleus.
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Offline mlorrey

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Re: Propellantless Field Propulsion and application
« Reply #650 on: 10/14/2009 11:07 AM »
I'm sorry about that. I was wondering what this had to do with the thread. Figured it was some comparison with electric propulsion that drifted a bit.

Glancing through the previous posts, I must admit that I don't like the use of electrons in a plasma. The problem is synchrotron radiation. If you're bouncing electrons in a chamber at a significant fraction of the speed of light, you are generating a lot of photons (not sure what their frequency would be) each time you bend the path of the electron. Maybe that could be used to  transfer energy to another plasma chamber.

That was my read too. Question: Why is it that electrons orbiting a nucleus do not emit photons unless they are dropping from higher orbits to lower ones? If an electron emits photons any time you bend its path, then the orbit of an electron around a nucleus should cause light emissions, but it does not. Since it does not, why doesn't it, and can we use that to our advantage with some field effect to make the electrons think they are in orbit around a nucleus while orbiting in the trap?

Obviously given electrons are so active in the plasma of a polywell reactor, there are conditions under which synchrotron radiation is limited. From my reading it appears electrons orbit pretty widely in and out of the potential well in the polywell.

Quote

How about some sort of lasing mechanism? Pump energy in to a crystal lattice of atoms, pushing the electrons to a higher energy state, on one side of the centrifuge and discharge on the other side. You might even be able to recycle most of the energy involved (excluding of course that expended on net thrust). It doesn't have the raw energy of relativistic electrons, but the energy density might be better.

I wonder if there may even be a way to do this with the nuclei themselves. That is, take a nucleus in the ground state, excite it to a nuclear isomer state and then decay. Glancing around, it appears a better way might be to find a nuclear isomer that decays mostly by beta (electron) decay rather than via gamma ray photons. Perhaps one could even reliably pump that electron in and out of the nucleus.


Thats an interesting idea. You would need to figure out how to get the electrons to emit from the nucleus all in the same direction. Perhaps by making a Bose-Einstein condensate of high atomic number atoms?
« Last Edit: 10/14/2009 11:12 AM by mlorrey »
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Offline khallow

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Re: Propellantless Field Propulsion and application
« Reply #651 on: 10/15/2009 05:05 PM »

Glancing through the previous posts, I must admit that I don't like the use of electrons in a plasma. The problem is synchrotron radiation. If you're bouncing electrons in a chamber at a significant fraction of the speed of light, you are generating a lot of photons (not sure what their frequency would be) each time you bend the path of the electron. Maybe that could be used to  transfer energy to another plasma chamber.

That was my read too. Question: Why is it that electrons orbiting a nucleus do not emit photons unless they are dropping from higher orbits to lower ones? If an electron emits photons any time you bend its path, then the orbit of an electron around a nucleus should cause light emissions, but it does not. Since it does not, why doesn't it, and can we use that to our advantage with some field effect to make the electrons think they are in orbit around a nucleus while orbiting in the trap?

The short answer is that synchrotron radiation is a classical effect. When you get to the quantum scale (as in the "lasing" example I mentioned), then the classical ideas no longer work. If the chambers were made small enough, then quantum effects (or more accurately a combination of quantum and relavistic effects) would dominate. Technically speaking, the lasing example is the chamber scheme at a quantum scale, but probably with lower energy levels.

Quote
Obviously given electrons are so active in the plasma of a polywell reactor, there are conditions under which synchrotron radiation is limited. From my reading it appears electrons orbit pretty widely in and out of the potential well in the polywell.

Another factor is whether something can reabsorb the emitted synchrotron radiation. That's one of the factors with the polywell. The plasma self-absorbs most of the synchrotron radiation produced. Only the bit produced near the edge of the plasma can escape.

Quote
Quote
How about some sort of lasing mechanism? Pump energy in to a crystal lattice of atoms, pushing the electrons to a higher energy state, on one side of the centrifuge and discharge on the other side. You might even be able to recycle most of the energy involved (excluding of course that expended on net thrust). It doesn't have the raw energy of relativistic electrons, but the energy density might be better.

I wonder if there may even be a way to do this with the nuclei themselves. That is, take a nucleus in the ground state, excite it to a nuclear isomer state and then decay. Glancing around, it appears a better way might be to find a nuclear isomer that decays mostly by beta (electron) decay rather than via gamma ray photons. Perhaps one could even reliably pump that electron in and out of the nucleus.

Thats an interesting idea. You would need to figure out how to get the electrons to emit from the nucleus all in the same direction. Perhaps by making a Bose-Einstein condensate of high atomic number atoms?

No idea here. My thinking here was to look for huge variation in energy density as one way to increase the effects of an MLT. Capacitors, superconducting inductors, and maybe some mechanical systems like micromechanical spinning disks seem pretty much the current or near future viable ways to efficiently store energy that can have a high store/discharge frequency. If you're trying to increase energy density variation by a bunch of orders of magnitude, that requires some sort of pretty exotic system, things like nuclear isomers, spinning miniature black holes, etc.
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Offline randomly

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Re: Propellantless Field Propulsion and application
« Reply #653 on: 10/17/2009 04:50 AM »
That was my read too. Question: Why is it that electrons orbiting a nucleus do not emit photons unless they are dropping from higher orbits to lower ones? If an electron emits photons any time you bend its path, then the orbit of an electron around a nucleus should cause light emissions, but it does not. Since it does not, why doesn't it, and can we use that to our advantage with some field effect to make the electrons think they are in orbit around a nucleus while orbiting in the trap?

Electrons don't actually orbit the nucleus despite the use of the name orbital. An orbital is a wave function that describes the probability distribution of an electron in that orbital. Don't try to apply any real world analogies at the quantum level, they are almost invariable wrong.

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Offline mlorrey

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Re: Propellantless Field Propulsion and application
« Reply #654 on: 10/17/2009 06:19 AM »
That was my read too. Question: Why is it that electrons orbiting a nucleus do not emit photons unless they are dropping from higher orbits to lower ones? If an electron emits photons any time you bend its path, then the orbit of an electron around a nucleus should cause light emissions, but it does not. Since it does not, why doesn't it, and can we use that to our advantage with some field effect to make the electrons think they are in orbit around a nucleus while orbiting in the trap?

Electrons don't actually orbit the nucleus despite the use of the name orbital. An orbital is a wave function that describes the probability distribution of an electron in that orbital. Don't try to apply any real world analogies at the quantum level, they are almost invariable wrong.

"Not only is the universe stranger than we imagine, it is stranger that we CAN imagine." -Sir Arthur Eddington

I'm aware of the probability distribution issue.

So, question: is the wavelength of the synchrotron radiation relative to the turn radius of electron in the betatron cavity? If so, is there an equation that describes how to calculate it?
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Offline randomly

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Re: Propellantless Field Propulsion and application
« Reply #655 on: 10/18/2009 02:14 AM »
So, question: is the wavelength of the synchrotron radiation relative to the turn radius of electron in the betatron cavity? If so, is there an equation that describes how to calculate it?
The wavelength of the synchrotron radiation is relative to the acceleration of the electron. The faster the acceleration the shorter the wavelength. Acceleration is the magnetic field times the velocity of the electron. The turn radius is velocity divided by magnetic field. So increasing the magnetic field is the only way to increase the acceleration.
For a given magnetic field, increasing velocity means increasing radius and acceleration is constant. Decreasing radius means decreasing velocity and again acceleration is same as before.

But take this all with a grain of salt as I only recall this stuff vaguely.

Offline mlorrey

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Re: Propellantless Field Propulsion and application
« Reply #656 on: 10/18/2009 04:36 AM »
So, question: is the wavelength of the synchrotron radiation relative to the turn radius of electron in the betatron cavity? If so, is there an equation that describes how to calculate it?
The wavelength of the synchrotron radiation is relative to the acceleration of the electron. The faster the acceleration the shorter the wavelength. Acceleration is the magnetic field times the velocity of the electron. The turn radius is velocity divided by magnetic field. So increasing the magnetic field is the only way to increase the acceleration.
For a given magnetic field, increasing velocity means increasing radius and acceleration is constant. Decreasing radius means decreasing velocity and again acceleration is same as before.

But take this all with a grain of salt as I only recall this stuff vaguely.

Ok, this is what I expected generally, I guess we need to find out at what point an electron emits synchrotron radiation. If emissions occur for each quanta of energy then using this as a thruster may be limited to a speed differential of less than one quanta, which would obviously put a damper on the upper end performance.

I would also suspect that there may be similar limits on the performance of solid dielectric capacitor based M-E thrusters, in which you wind up generating a lot of radiation emissions when the mass variations exceed a certain percentage of atomic mass, which drains energy.
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Offline randomly

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Re: Propellantless Field Propulsion and application
« Reply #657 on: 10/18/2009 05:40 AM »
I would also suspect that there may be similar limits on the performance of solid dielectric capacitor based M-E thrusters, in which you wind up generating a lot of radiation emissions when the mass variations exceed a certain percentage of atomic mass, which drains energy.

I think dialectric losses will rule out any use of solid dialectrics. Losses will be prohibitive.

Offline mlorrey

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Re: Propellantless Field Propulsion and application
« Reply #658 on: 10/19/2009 10:15 AM »
I would also suspect that there may be similar limits on the performance of solid dielectric capacitor based M-E thrusters, in which you wind up generating a lot of radiation emissions when the mass variations exceed a certain percentage of atomic mass, which drains energy.

I think dialectric losses will rule out any use of solid dialectrics. Losses will be prohibitive.

Well you don't know that for a fact, try reading Woodward's work first.
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Offline randomly

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Re: Propellantless Field Propulsion and application
« Reply #659 on: 10/20/2009 03:08 PM »
Well you don't know that for a fact, try reading Woodward's work first.
That is true. I've only read a little material about Woodward's work so far.
I didn't mean to imply that dialectric losses would preclude observation of the phenomenon. I meant that the losses would probably preclude it's practical application as a space drive. The energy requirements would be so high for useful amount of thrust that it wouldn't be worth it.

I'm not positive I'm correct, but it seems a significant point of concern.

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