Resonant coupling between ion bounce in a potential well and the potential relaxation instability

Journal Article · Sat Jan 01 00:00:00 EST 1994 · Physics of Plasmas; (United States)

DOI:https://doi.org/10.1063/1.870555· OSTI ID:6691375

Popa, G; Schrittwieser, R ^[1]

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1. Institute for Ion Physics, University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck (Austria)

When in a double plasma machine (DP-machine) plasma is produced solely in the source chamber, not only ions but also electrons can leak through the separating grid into the target chamber, so that a low-density plasma forms there. The electrons are trapped by the traveling ion space charge and can thereby overcome the strongly negative grid bias. The investigations presented here show that a positive space-charge forms behind the grid in the target chamber and a deep potential well is formed around the grid. When the anode of the target chamber is biased positively, under certain conditions a low-frequency instability is observed in the target chamber, the properties of which indicate a potential relaxation oscillation, somewhat similar to the potential relaxation instability in a quiescent plasma machine (Q machine). The frequency of the instability is determined by the ion transit time through a thin layer of the target chamber plasma. In addition, resonant coupling occurs between this frequency and the bounce frequency of ions in the potential well around the grid.

• OSTI ID: 6691375
• Journal Information: Physics of Plasmas; (United States), Vol. 1:1; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
PLASMA SHEATH
PLASMA INSTABILITY
GRIDS
POTENTIALS
Q DEVICES
RESONANCE
SPACE CHARGE
TRAPPED ELECTRONS
ELECTRODES
ELECTRONS
ELEMENTARY PARTICLES
FERMIONS
INSTABILITY
LEPTONS
OPEN PLASMA DEVICES
THERMONUCLEAR DEVICES
700350* - Plasma Production
Heating
Current Drive
& Interactions- (1992-)
700340 - Plasma Waves
Oscillations
& Instabilities- (1992-)