Title :
Adiabatic plasma expansion in a magnetic nozzle
Author :
Sheehan, J.P. ; Longmier, Benjamin W. ; Bering, Edgar A. ; Olsen, Christopher S. ; Squire, Jared P. ; Carter, Mark D. ; Cassady, Leonard D. ; Chang Diaz, Franklin R. ; Glover, Timothy W. ; Hin, Andrew V. ; Ballenger, Maxwell G.
Author_Institution :
Univ. of Michigan, Ann Arbor, MI, USA
Abstract :
Summary form only given. A mechanism for ambipolar ion acceleration in a magnetic nozzle is proposed. The plasma is adiabatic in the diverging section of a magnetic nozzle so any energy lost by the electrons must be transferred to the ions via the electric field. Fluid theory indicates that the change in average electron energy equals the change in plasma potential. These predictions were compared to measurements in the VX-200 experiment which has conditions conducive to ambipolar ion acceleration. A planar Langmuir probe was used to measure the plasma potential, electron density, and electron temperature for a range of mass flow rates and power levels. Axial profiles of those parameters were also measured, verifying the adiabatic ambipolar fluid theory.
Keywords :
Langmuir probes; electron density; ion accelerators; nozzles; plasma accelerators; plasma density; plasma dielectric properties; plasma magnetohydrodynamics; plasma transport processes; VX-200 experiment; adiabatic ambipolar fluid theory; adiabatic plasma expansion; ambipolar ion acceleration; average electron energy; axial profiles; diverging section; electric field; electron density; electron temperature; energy lost; magnetic nozzle; mass flow rates; planar Langmuir probe; plasma potential; power levels;
Conference_Titel :
Plasma Sciences (ICOPS) held with 2014 IEEE International Conference on High-Power Particle Beams (BEAMS), 2014 IEEE 41st International Conference on
Conference_Location :
Washington, DC
Print_ISBN :
978-1-4799-2711-1
DOI :
10.1109/PLASMA.2014.7012590
