Accession Number : AD0712281

Title :   PULSED LANGMUIR PROBE MEASUREMENT OF IONIZATION IN A HIGH-PRESSURE PLASMA,

Corporate Author : VICTORIA UNIV (BRITISH COLUMBIA) DEPT OF PHYSICS

Personal Author(s) : Clements,R. M. ; Smy,P. R.

Report Date : 16 MAR 1970

Pagination or Media Count : 5

Abstract : Measurements with a negatively pulsed probe in an atmospheric-pressure high-density plasma over wide ranges of ionization density (10 to the 15th power to 10 to the 18th power/cubic meters), probe voltage (10-400 volts), and flow velocity (5-40 m/s have confirmed previous results obtained by Thomas, working at a single voltage and flow velocity in which the current initially falls off with 1/t to the y power dependence where y approximately 0.58 and t = time. The results together with those of Thomas show good agreement with a theory based on a physical model involving space-charge controlled expansion of the sheath towards its final position. It is expected that this technique of probe operation will afford a simple and sometimes unique method of measuring ionization density with excellent spatial resolution, under high-pressure conditions where the plasma velocity relative to the probe is not accurately known (for atmospheric-pressure dc measurements this factor often becomes significant with flow velocities >0.1-1m/s). (Author)

Descriptors :   (*PLASMA SHEATHS, IONIZATION), (*LANGMUIR PROBES, HIGH PRESSURE), MODEL THEORY, IONIC CURRENT, CANADA

Subject Categories : Test Facilities, Equipment and Methods
      Plasma Physics and Magnetohydrodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE