Using Planar Probes to Estimate the Hall Electron Drift Speed in Magnetized Plasma
✍ Scribed by A. Vetushka; S. K. Karkari; Y. Aranda-Gonzalvo; J. W. Bradley
- Publisher
- John Wiley and Sons
- Year
- 2004
- Tongue
- English
- Weight
- 415 KB
- Volume
- 44
- Category
- Article
- ISSN
- 0005-8025
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✦ Synopsis
Abstract
A circular planar probe of diameter 4 mm has been used to determine the ratio of the electron E × B drift speed V~d~ to the thermal speed V~th~ in the bulk plasma of a magnetron discharge. It is found that when the probe is orientated into the E × B drift, with its surface parallel to the local B‐field, significantly higher electron saturation currents are detected than when the probe is orientated away from the drift (i.e. 180 degrees from this orientation). Using the electron and ion saturation current measurements and a simple model of the anisotropic plasma‐probe system, which assumes both Hall and collisional cross‐field transport, V~d~/V~th~ has been determined at different positions in the bulk plasma. The maximum in V~d~/V~th~ is found to be about 0.14 (corresponding to V~d~ = 1 · 10^5^ ms^–1^) and the measured distribution of drift current agrees well with data that was found in a previous study, in which V~d~ was determined from the knowledge of E and B, namely V~d~ = E × B/B^2^, and with V~th~ determined from electron temperature measurements, i.e. V~th~ = (2kT~e~/m~e~)^1/2^. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)