Title :
Initial experiments of a new permanent magnet helicon thruster
Author :
Sheehan, J.P. ; Longmier, B.W. ; Reese, I.M. ; Collard, T.A. ; Ebersohn, F.H. ; Dale, E.T. ; Wachs, B.N. ; Ostermann, M.E.
Author_Institution :
Univ. of Michigan, Ann Arbor, MI, USA
Abstract :
Summary form only given. A new design for a permanent magnet helicon thruster is presented. Its small plasma volume (~10 cm3) and low power requirements (<;100 W) make it ideal for propelling nanosatellites (<;10 kg). The magnetic field reached a maximum of 600 G in the throat of a converging-diverging nozzle and decreased to 0.5 G, the strength of earth´s magnetic field, within 50 cm allowing the entire exhaust plume to develop in the vacuum chamber without being affected by the chamber walls. Low gas flow rates (~10 sccm) and high pumping speeds (~10,000 l/s) were used to more closely approximate the conditions of space. A parametric study of the thruster operational parameters was performed to determine its capabilities as both a thruster and as a plasma source for magnetic nozzle experiments. The plasma density, electron temperature, and plasma potential in the plume were measured with Langmuir probes, double probes, and emissive probes. These measurements characterized the ion acceleration mechanism which produces thrust. Thrust measurements were made with an innovative micronewton thrust stand. Measurements were compared to predictions made with fluid theory and particle-in-cell simulations.
Keywords :
Langmuir probes; nozzles; plasma accelerators; plasma density; plasma magnetohydrodynamics; plasma sources; plasma temperature; Earth magnetic field strength; Langmuir probes; converging-diverging nozzle; double probes; electron temperature; emissive probes; exhaust plume; fluid theory; gas flow rates; ion acceleration mechanism; magnetic nozzle experiments; micronewton thrust stand; nanosatellite propulsion; particle-in-cell simulations; permanent magnet helicon thruster; plasma density; plasma potential; plasma source; plasma volume; pumping speeds; thrust measurements; vacuum chamber; Atmospheric measurements; Particle measurements; Permanent magnets; Plasma measurements; Plasmas; Probes; Temperature measurement;
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.2014.7012225