Electrostatic ion-cyclotron wave experiments in the WVU Q machine

Author

Koepke, Mark E. ; Amatucci, William E.

Author_Institution

Dept. of Phys., West Virginia Univ., Morgantown, WV, USA

Volume

20

Issue

6

fYear

1992

fDate

12/1/1992 12:00:00 AM

Firstpage

631

Lastpage

635

Abstract

The influence of transverse, localized, DC electric fields (TLEs) on the current-driven electrostatic ion-cyclotron (CDEIC) instability is being investigated in a Q machine. A small (diameter ~10 ion gyroradii) segmented disk electrode is being used to excite the mode in a narrow electron-current channel along which exists a radial electric field between regions that magnetically map to the different circular segments (separated by a radial gap of ~3 ion gyroradii). Experiments aimed at demonstrating a TLE dependence in the threshold current for mode excitation are described. A comparison of observed and predicted mode frequencies over a range of magnetic field strengths is presented for the benchmark case of no applied transverse electric field. When the electric field is present, ion-cyclotron fluctuations are observed for cases in which the current is below the CDEIC instability threshold

Keywords

electric field effects; plasma devices; plasma instability; WVU Q machine; current-driven electrostatic ion-cyclotron instability; electron-current channel; electrostatic ion cyclotron wave experiments; instability threshold; magnetic field strengths; magnetic mapping; radial gap; segmented disk electrode; transverse localised DC electric fields; Electrodes; Electrostatics; Fluctuations; Frequency; Magnetic resonance; Magnetosphere; Plasma applications; Plasma properties; Plasma waves; Threshold current;

fLanguage

English

Journal_Title

Plasma Science, IEEE Transactions on

Publisher

ieee

ISSN

0093-3813

Type

jour

DOI

10.1109/27.199504

Filename

199504