Title :
Assessment of Plasma-Flow Effect on Langmuir Triple-Probe Operation via Kinetic Simulation
Author :
Deline, Christopher ; Choinière, èric ; Gilchrist, Brian E.
Author_Institution :
Univ. of Michigan, Ann Arbor, MI, USA
Abstract :
A self-consistent steady-state 2-D kinetic plasma solver has been applied to the problem of Langmuir triple-probe plasma diagnostic measurements in a flowing collisionless plasma. The triple-probe response is simulated for ion Mach numbers M = 0 - 5 and probe radii rp = 1 - 90 lambdaD (Debye length). Results indicate that a high probe radius and high ion Mach numbers more closely approximate the ideal thin-sheath triple-probe response. Small probe radii on the order of the Debye length can result in temperature errors of the ideal model greater than 70% for a probe bias of 20 V. An analytical approximation is described, approximating triple-probe measurement offsets given arbitrary probe bias and probe radius and ion Mach numbers 0 < M < 5. The fitting error from this analytical approximation is estimated at 2%-6%.
Keywords :
Langmuir probes; plasma diagnostics; plasma sheaths; plasma simulation; Langmuir triple-probe operation; kinetic simulation; plasma diagnostics; plasma simulation; plasma-flow effect; plasma-sheath; Flowing collisionless plasma; Langmuir triple probe; kinetic plasma model; plasma diagnostics; plasma-sheath simulation;
Journal_Title :
Plasma Science, IEEE Transactions on
DOI :
10.1109/TPS.2009.2025277