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Title: Kinetic simulation of the O-X conversion process in dense magnetized plasmas

One scheme for heating a dense magnetized plasma core, such as in a tokamak, involves launching an ordinary (O) electromagnetic wave at the low density edge. It is converted to a reflected extraordinary (X) electromagnetic wave under certain conditions, and then transformed into an electron Bernstein wave able to reach high density regions inaccessible to most other waves. The O-X mode conversion is important in heating and diagnostic processes in different devices such as tokamaks, stellarators, and some types of pinches. The goal of this study has been to demonstrate that the kinetic particle-in-cell (PIC) scheme is suitable for modeling the O-X conversion process as the first step toward a more complete simulation of O-X-B heating. The O-X process is considered and simulated with a kinetic particle model for parameters of the TJ-II stellarator using the PIC code, XOOPIC. This code is able to model the non-monotonic density and the magnetic profile of the TJ-II stellarator. It can also statistically represent the self-consistent distribution function of the plasma, which has not been possible in previous fluid models. By considering the electric and magnetic components of launched and reflected waves, the O-mode and X-mode waves can be detected, and the O-Xmore » conversion can be demonstrated. In this work, the optimum angle for conversion efficiency, as predicted by the previous theory and experimentally confirmed, is used. Via considering the power of the launched O-mode wave and the converted X-mode wave, the efficiency of 63% for O-X conversion for the optimum theoretical launch angle of 47{sup ∘} is obtained, which is in good agreement with efficiencies computed via full-wave simulations.« less
Authors:
 [1] ;  [2] ;  [3] ;  [1] ;  [4]
  1. Physics Department, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of)
  2. (United States)
  3. Department of Electrical and Computer Engineering, Michigan State University, Michigan 48824-1226 (United States)
  4. STFC Rutherford Appleton Laboratory, Didcot (United Kingdom)
Publication Date:
OSTI Identifier:
22218539
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 20; Journal Issue: 10; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; BERNSTEIN MODE; COMPUTERIZED SIMULATION; DISTRIBUTION FUNCTIONS; ELECTROMAGNETIC RADIATION; ELECTRONS; MAGNETOHYDRODYNAMICS; MODE CONVERSION; PLASMA CONFINEMENT; PLASMA DENSITY; PLASMA INSTABILITY; PLASMA SIMULATION; PLASMA WAVES; STELLARATORS; TOKAMAK DEVICES; X CODES