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

fYear

2014

fDate

25-29 May 2014

Firstpage

1

Lastpage

1

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;

fLanguage

English

Publisher

ieee

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

Type

conf

DOI

10.1109/PLASMA.2014.7012590

Filename

7012590