Accession Number:

AD0723529

Title:

Ion Temperature Sensitive Effect in Transient Langmuir Probe Response

Descriptive Note:

Corporate Author:

MASSACHUSETTS INST OF TECH CAMBRIDGE FLUID MECHANICS LAB

Personal Author(s):

Report Date:

1971-02-01

Pagination or Media Count:

61.0

Abstract:

A theory is presented for a method, recently proposed by Hester and Sonin, of determining the ion temperature in a plasma by measuring the transient current response of a highly negative, cylindrical Langmuir probe under conditions where collection is collision-free and the ratio of probe radius to Debye length is small. The ion component of the current does not approach its final steady-state value monotonically, but exhibits a strong, ion temperature dependent overshoot in the first few ion-plasma periods following the biasing of the probe. Analytical formulae are derived for a Maxwellian plasma, and convenient graphical results are presented. The possible masking of the overshoot by a transient displacement current is discussed and found to be often negligible. For other conditions an alternative measuring method is suggested in which the contribution of the displacement current cancels out.

Subject Categories:

  • Plasma Physics and Magnetohydrodynamics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE