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Title: Experimental investigation of the early stage of the PRI in a weakly magnetized discharge plasma

Abstract

An instability triggered by a positive electrode in a weakly magnetized discharge plasma is studied experimentally. The instability is excited by a 2 cm diameter plane electrode, which is immersed into the plasma column with its surface perpendicular to the magnetic field lines. The magnetic field density is 0.02 T, the Larmor radius for argon ions is around 1 cm and for electrons around 0.1 mm. The electron temperature is kT{sub e} = 2 eV, the ion temperature kT{sub i} = 0.1 eV and the plasma density n = 2-8 x 10{sup 10} cm{sup -3}. The oscillations of the electrode current appear, when the electrode bias exceeds the plasma potential. In order to observe the early stage of the instability a voltage step is applied to the exciter electrode by the use of a very fast (150 ns rise time) FET power switch, controlled by a signal generator. The pulse from the signal generator is also used as a trigger for the digitizing oscilloscope. Time development of the plasma density after the application of the pulse is measured by a cylindrical Langmuir probe. The plasma density is believed to be proportional to the ion saturation current, I{sub is}, to themore » negatively biased (-50 V) Langmuir probe. The exciter electrode is moved in the axial direction, that is along the magnetic field lines and the probe is moved across the magnetic field lines - the radial direction.« less

Authors:
; ;  [1]
  1. Univ. of Ljubljana (Slovenia)
Publication Date:
OSTI Identifier:
232832
Report Number(s):
CONF-950749-
TRN: 97:015765
Resource Type:
Conference
Resource Relation:
Conference: 22. international conference on phenomena in ionized gases, Hoboken, NJ (United States), 31 Jul - 4 Aug 1995; Other Information: PBD: 1995; Related Information: Is Part Of XXII International conference on phenomena in ionized gases. Contributed papers 3; Becker, K.H.; Carr, W.E.; Kunhardt, E.E. [eds.]; PB: 120 p.
Country of Publication:
United States
Language:
English
Subject:
66 PHYSICS; ELECTRIC DISCHARGES; PLASMA INSTABILITY; MAGNETIZATION; ELECTRODES; PLASMA DENSITY

Citation Formats

Gyergyek, T, Cercek, M, and Stanojevic, M. Experimental investigation of the early stage of the PRI in a weakly magnetized discharge plasma. United States: N. p., 1995. Web.
Gyergyek, T, Cercek, M, & Stanojevic, M. Experimental investigation of the early stage of the PRI in a weakly magnetized discharge plasma. United States.
Gyergyek, T, Cercek, M, and Stanojevic, M. 1995. "Experimental investigation of the early stage of the PRI in a weakly magnetized discharge plasma". United States.
@article{osti_232832,
title = {Experimental investigation of the early stage of the PRI in a weakly magnetized discharge plasma},
author = {Gyergyek, T and Cercek, M and Stanojevic, M},
abstractNote = {An instability triggered by a positive electrode in a weakly magnetized discharge plasma is studied experimentally. The instability is excited by a 2 cm diameter plane electrode, which is immersed into the plasma column with its surface perpendicular to the magnetic field lines. The magnetic field density is 0.02 T, the Larmor radius for argon ions is around 1 cm and for electrons around 0.1 mm. The electron temperature is kT{sub e} = 2 eV, the ion temperature kT{sub i} = 0.1 eV and the plasma density n = 2-8 x 10{sup 10} cm{sup -3}. The oscillations of the electrode current appear, when the electrode bias exceeds the plasma potential. In order to observe the early stage of the instability a voltage step is applied to the exciter electrode by the use of a very fast (150 ns rise time) FET power switch, controlled by a signal generator. The pulse from the signal generator is also used as a trigger for the digitizing oscilloscope. Time development of the plasma density after the application of the pulse is measured by a cylindrical Langmuir probe. The plasma density is believed to be proportional to the ion saturation current, I{sub is}, to the negatively biased (-50 V) Langmuir probe. The exciter electrode is moved in the axial direction, that is along the magnetic field lines and the probe is moved across the magnetic field lines - the radial direction.},
doi = {},
url = {https://www.osti.gov/biblio/232832}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Dec 31 00:00:00 EST 1995},
month = {Sun Dec 31 00:00:00 EST 1995}
}

Conference:
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