Plasma-surface interactions with ICRF antennas and lower hybrid grills in Tore Supra
- Oak Ridge National Lab., TN (United States)
- Association Euratom-CEA, Centre d`Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee
- Oak Ridge National Lab., TN (United States); and others
The edge plasma interactions of the actively cooled radio-frequency heating launchers in Tore Supra- ion-cyclotron range-of-frequencies (ICRF) antennas and lower-hybrid (LH) grills-are studied using infrared video imaging. On the two-strap ICRF antennas, operated in fast-wave electron heating or current drive mode, hot spots with temperatures of 500-900{degrees} C are observed by the end of 2-s power pulses of 2 MW per antenna. The distribution and maximum values of temperature are determined principally by the relative phase of the two antenna straps: dipole (heating) phasing results in significantly less antenna heating than does 90` (current drive) phasing. Transient heat fluxes of 1-20 MW/m{sup 2} are measured on the lateral protection bumpers at ICRF turn-on; these fluxes are primarily a function of plasma and radio frequency (rf) control, and are not simply correlated with the strap phasing or the final surface temperature distributions. The remarkable feature of the lower hybrid edge interaction is the production of beams of heat flux in front of the grills; these beams propagate along the helical magnetic field lines and can deliver fluxes of 5-10 MW/m{sup 2} over areas of several cm{sup 2} to plasma-facing components such as the grill or antenna lateral bumpers. Both the ICRF and LH phenomena appear to result from the acceleration of particles by the near fields of the launchers. Modeling of the heat flux deposition on components and its relation to sputtering processes is presented, and possibilities for controlling these interactions are discussed.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC05-96OR22464
- OSTI ID:
- 390567
- Report Number(s):
- CONF-960569-9; ON: DE96015007; TRN: 96:028422
- Resource Relation:
- Conference: 12. international conference on plasma surface interactions in controlled fusion devices, Saint-Raphael (France), 20-26 May 1996; Other Information: PBD: [1996]
- Country of Publication:
- United States
- Language:
- English
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