Simulations of rf-driven sheath formation in two dimensions

Journal Article · Thu Oct 01 04:00:00 EDT 1992 · Physics of Fluids B; (United States)

DOI:https://doi.org/10.1063/1.860381· OSTI ID:7258942

Riyopoulos, S; Grossmann, W; Drobot, A; Kress, M ^[1]

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1. Science Applications International Corporation, McLean, Virginia 22102 (United States)

The results from two-dimensional particle simulations of sheath formation around periodic metal arrays placed inside magnetized plasmas and driven by oscillating voltages are reported. The main goal is the modeling of the plasma interaction with the Faraday bars surrounding the antennas during ion cyclotron tokamak heating. The study of the time-averaged potentials shows that the two-dimensional sheath structure depends on both the sheath length-to-thickness ratio and the inclination of the magnetic lines. The equipotential surfaces form closed, nested cells between adjacent bars. When the magnetic lines are nearly perpendicular to the potential gradients, the ion motion is dominated by the {bold E}{times}{bold B} drift, and ion streamlines form vortices around the equipotentials. At larger inclinations of the magnetic lines, the flow decouples from the equipotentials and ion transport is mainly along the potential gradients. The critical angle for the transition from vortex circulation to field aligned flow is computed. The effects of the cross-field ion transport on the sheath properties are discussed. It is shown that the sheath length and the magnetic line inclination affect the sheath scaling in the two-dimensional case. The one-dimensional theory results are recovered in the limit of high length-to-thickness ratio and large inclination of the magnetic lines.

• DOE Contract Number: AC03-88ER53270
• OSTI ID: 7258942
• Journal Information: Physics of Fluids B; (United States), Journal Name: Physics of Fluids B; (United States) Vol. 4:10; ISSN 0899-8221; ISSN PFBPE
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700350* -- Plasma Production
Heating
Current Drive
& Interactions-- (1992-)
CLOSED PLASMA DEVICES
CROSSED FIELDS
ELECTROMAGNETIC RADIATION
HEATING
MAGNETIZATION
ORBITS
PLASMA HEATING
PLASMA SHEATH
PLASMA SIMULATION
RADIATIONS
RADIOWAVE RADIATION
SIMULATION
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
TWO-DIMENSIONAL CALCULATIONS
VORTICES