http://www.esa.int/gsp/ACT/pro/op/IEC/IEC_Overview.htm
Inertial Electrostatic Confinement Thrusters
http://erps.spacegrant.org/uploads/imag ... 11-311.pdf
On the kinetic modeling of fusion processes in IEC devices
http://pure.ltu.se/portal/files/4268060 ... 591366.pdf
Inertial Electrostatic Confinement Devices as an Advanced Electric Propulsion System
IEC Propulsion research in Europe
Re: IEC Propulsion research in Europe
Some interesting reading. A couple of quick points. George Miley has proposed IEC thrusters several years ago, and characterized some advantages over more conventional ion thrusters.
The Jet vs the Star mode in the glow discharge IEC device (fusor) is reversed in the thesis. The Star mode tends to occur at lower pressures than the Jet (electron beam I believe). The plasma appearance progresses from the what I call the adherent mode (much of the glow proximal to the wires) to Bugle mode to Jet mode and finally Star mode as the pressure drops. There are other variables but this is the general pattern. These beams reflect a predominance of charged particles flowing between the wires. In a fusor this increases the transparency of the grid from perhaps 80 percent to perhaps 95%. People have tried to improve this transparency and this is of course one of the prime goals of the Polywell, where the transparency has been claimed to be as much as 99.99 percent or more. Note that this transparency is related to the positive ions, the electrons only make ~ 1 pass before hitting the vacuum vessel walls. The Elmore Tuck Watson scheme reversed the orientation so that electrons make more passes, but the ions are now lost, though if the ions can be introduced at strategic radii, the confined electrons may confine them some with a potential well. The Polywell is again an extension of this with additional magnetic components that push the electron confinement (effectively the grid transparency) even further.
In terms of a space rocket thruster, the question of efficiency is different. You are not trying to break even with fusion. In this regard the Jet mode serves as a method for focusing a beam of high energy charged particles in a favorable direction. In some ways it is similar to an ion thruster (literally), but it may have some advantages in thrust vs input energy and higher ISP and possible greater power than that achieved with Hall effect, etc. ion thrusters. How would it compare with a VASMIR type of thruster?.
Dan Tibbets
The Jet vs the Star mode in the glow discharge IEC device (fusor) is reversed in the thesis. The Star mode tends to occur at lower pressures than the Jet (electron beam I believe). The plasma appearance progresses from the what I call the adherent mode (much of the glow proximal to the wires) to Bugle mode to Jet mode and finally Star mode as the pressure drops. There are other variables but this is the general pattern. These beams reflect a predominance of charged particles flowing between the wires. In a fusor this increases the transparency of the grid from perhaps 80 percent to perhaps 95%. People have tried to improve this transparency and this is of course one of the prime goals of the Polywell, where the transparency has been claimed to be as much as 99.99 percent or more. Note that this transparency is related to the positive ions, the electrons only make ~ 1 pass before hitting the vacuum vessel walls. The Elmore Tuck Watson scheme reversed the orientation so that electrons make more passes, but the ions are now lost, though if the ions can be introduced at strategic radii, the confined electrons may confine them some with a potential well. The Polywell is again an extension of this with additional magnetic components that push the electron confinement (effectively the grid transparency) even further.
In terms of a space rocket thruster, the question of efficiency is different. You are not trying to break even with fusion. In this regard the Jet mode serves as a method for focusing a beam of high energy charged particles in a favorable direction. In some ways it is similar to an ion thruster (literally), but it may have some advantages in thrust vs input energy and higher ISP and possible greater power than that achieved with Hall effect, etc. ion thrusters. How would it compare with a VASMIR type of thruster?.
Dan Tibbets
To error is human... and I'm very human.
Re: IEC Propulsion research in Europe
Hey Guys,
For what it is worth, Carl Detrich at MIT did his PhD thesis on IEC for space propulsion in 2007. Then he went on to found a company which builds flying cars. Somewhere I have a link to his thesis.
http://web.mit.edu/invent/a-winners/a-dietrich.html
For what it is worth, Carl Detrich at MIT did his PhD thesis on IEC for space propulsion in 2007. Then he went on to found a company which builds flying cars. Somewhere I have a link to his thesis.
http://web.mit.edu/invent/a-winners/a-dietrich.html