Numerical investigation of fast-wave propagation and radio-frequency sheath interaction with a shaped tokamak wall

Journal Article · Wed Jul 15 00:00:00 EDT 2015 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4926449· OSTI ID:22490009

Myra, J. R.; D'Ippolito, D. A. ^[1]

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1. Lodestar Research Corporation, 2400 Central Avenue P-5, Boulder, Colorado 80301 (United States)

Interactions between propagating fast waves and radio-frequency (RF) sheaths in the ion cyclotron range of frequencies are numerically investigated based on a cold fluid plasma model coupled with a sheath boundary condition. In this two-dimensional study, the capability of the finite element code rfSOL, which was developed in previous numerical work, is extended to analyze self-consistent RF sheath-plasma interaction problems in a tokamak with a non-circular cross-section. It is found that a large sheath voltage is generated near the edges of the limiter-shaped deformation as a result of the conversion from fast to slow waves on the sheaths. The sheath voltage associated with this conversion is particularly significant in the localized region where the contact angle between the magnetic field line and the conducting wall varies rapidly along the curved sheath surface, which is consistent with the results in previous one-dimensional theoretical work. The dependences of the RF sheaths on various parameters in plasma such as the toroidal wavenumber, edge plasma density, and the degree of the RF wave absorption in the core region are also examined in detail.

• OSTI ID: 22490009
• Journal Information: Physics of Plasmas, Vol. 22, Issue 7; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ABSORPTION
BOUNDARY CONDITIONS
COLD PLASMA
CROSS SECTIONS
DEFORMATION
ELECTRIC POTENTIAL
FINITE ELEMENT METHOD
INTERACTIONS
ION PLASMA WAVES
MAGNETIC FIELDS
ONE-DIMENSIONAL CALCULATIONS
PLASMA DENSITY
PLASMA SHEATH
RADIOWAVE RADIATION
TOKAMAK DEVICES
TWO-DIMENSIONAL CALCULATIONS
WAVE PROPAGATION