2D modeling of DC potential structures induced by RF sheaths with transverse currents in front of ICRF antenna
- LPMIA, UMR CNRS 7040, Univ. Henri Poincare, Nancy 1, BP 239, 54506 Vandoeuvre Cedex (France)
- Association Euratom-CEA-DRFC, CEA Cadarache, 13108 St. Paul les Durance (France)
Understanding DC potential generation in front of ICRF antennas is crucial for long pulse high RF power systems. DC potentials are produced by sheath rectification of these RF potentials. To reach this goal, near RF parallel electric fields have to be computed in 3D and integrated along open magnetic field lines to yield a 2D RF potential map in a transverse plane. DC potentials are produced by sheath rectification of these RF potentials. As RF potentials are spatially inhomogeneous, transverse polarization currents are created, modifying RF and DC maps. Such modifications are quantified on a 'test map' having initially a Gaussian shape and assuming that the map remains Gaussian near its summit,the time behavior of the peak can be estimated analytically in presence of polarization current as a function of its width r0 and amplitude {phi}0 (normalized to a characteristic length for transverse transport and to the local temperature). A 'peaking factor' is built from the DC peak potential normalized to {phi}0, and validated with a 2D fluid code and a 2D PIC code (XOOPIC). In an unexpected way transverse currents can increase this factor. Realistic situations of a Tore Supra antenna are also studied, with self-consistent near fields provided by ICANT code. Basic processes will be detailed and an evaluation of the 'peaking factor' for ITER will be presented for a given configuration.
- OSTI ID:
- 20726312
- Journal Information:
- AIP Conference Proceedings, Vol. 787, Issue 1; Conference: 16. topical conference on radio frequency power in plasmas, Park City, UT (United States), 11-13 Apr 2005; Other Information: DOI: 10.1063/1.2098227; (c) 2005 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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