Induced magnetic-field effects in inductively coupled plasmas

Journal Article · Wed May 01 04:00:00 EDT 1996 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.871979· OSTI ID:282898

Cohen, R H; Rognlien, T D ^[1]

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1. Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

In inductive plasma sources, the rapid spatial decay of the electric field arising from the skin effect produces a large radio frequency (RF) magnetic field via Faraday{close_quote}s law. It was previously shown that this magnetic field leads to a reduction of the electron density in the skin region, as well as a reduction in the collisionless heating rate. The electron deficit leads to the formation of an electrostatic potential which pulls electrons in to restore quasineutrality. Here the electron density calculation is extended to include both the induced and electrostatic fields. If the wave frequency is not too low, the ions respond only to the averaged fields, and hence the electrostatic field is oscillatory, predominantly at the second harmonic of the applied field. The potential required to establish a constant electron density is calculated and compared with numerical orbit-code calculations. For times short compared to ion transit times, the quasineutral density is just the initial ion density. For timescales long enough that the ions can relax, the density profile can be found from the solution of fluid equations with an effective (ponderomotive-like) potential added. Although the time-varying electrostatic potential is an extra source of heating, the net effect of the induced magnetic and electrostatic fields through trapping, early turning, and direct heating is a significant reduction in collisionless heating for parameters of interest. {copyright} {ital 1996 American Institute of Physics.}

• Research Organization: Lawrence Livermore National Laboratory
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 282898
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 5 Vol. 3; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ELECTRIC DISCHARGES
ELECTRON DENSITY
INDUCTIVELY COUPLED PLASMA
ION DENSITY
MAGNETIC FIELD EFFECTS
PLASMA HEATING
PLASMA PRODUCTION
POTENTIALS
SKIN EFFECT
WALL EFFECTS