Nonlinear instability dynamics in a high-density, high-beta plasma

Date

2009-02-18

Authors

Corr, C. S.
Boswell, R. W.

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Volume Title

Publisher

American Institute of Physics (AIP)

Abstract

Entrainment and periodic pulling of an ion acoustic instability have been observed in the power spectra of a low-pressure high-beta plasma. The observed nonlinear phenomena can be modeled by using the van der Pol equation with a forcing term. Experimental results of the nonlinear processes are presented. Ion density fluctuations are detected on a negatively biased Langmuir probe for magnetic fields and input powers above 30 G and 900 W at 7.2 MHz respectively, and gas pressure below 1.5 mTorr. This low-frequency instability is observed in the central plasma blue core (argon II emission) and can be controlled by amplitude modulation of the radio frequency input power at frequencies close to the instability frequency.

Description

Keywords

Keywords: Argon; Emission spectroscopy; Magnetic fields; Nonlinear equations; Plasma diagnostics; Plasmas; Acoustic instabilities; Forcing terms; Gas pressures; High densities; High-beta plasmas; Input power; Ion densities; Low-frequency instabilities; Non-linear i

Citation

Source

Physics of Plasmas

Type

Journal article

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DOI

10.1063/1.3074790

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