Mach Probe Measurements in Unmagnetized Plasmas with Subsonicand Supersonic Flow

✍ Scribed by A. Ando; T. K. Watanabe; T. Makita; H. Tobari; K. Hattori; M. Inutake

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 161 KB
• Volume: 46
• Category: Article
• ISSN: 0005-8025
• DOI: 10.1002/ctpp.200610011

✦ Synopsis

Abstract

Characteristics of an up‐down type Mach probe are investigated by using a directional Langmuir probe (DLP) in unmagnetized plasmas with subsonic and supersonic flow produced by a magneto‐plasma‐dynamic arcjet (MPDA). The ion acoustic Mach number M~i~ is derived from plasma flow velocity U~p~ and ion temperature T~i~ measured by spectroscopy and electron temperature T~e~ by Langmuir probe. The obtained values of M~i~ are compared to the DLP data in various conditions of plasma flow and the coefficient of M~c~ in the Mach probe formula,M~i~ = M~c~ ln(J~up~/J~down~ ) , is evaluated. The obtained data are also compared with Hutchinson's PIC simulation results in an unmagnetized plasma and are in good agreement with each other. The dependence of ln(J~up~/J~down~ ) on cos__ϕ__ can be expressed as a quadratic function under subsonic (M~i~ < 1) and supersonic (M~i~ > 1) flow, so that the up‐down type Mach probe can detect the components of plasma flow vector even when the probe collection surface inclines to plasma flow direction. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)