Edge plasma density convection during ion cyclotron resonance heating on Tore Supra
The two-dimensional (2D) edge plasma density distribution in the scrape off layer magnetically connected to the ion cyclotron resonance heating (ICRH) antennae is studied experimentally and numerically in the tokamak Tore Supra. A local density decrease in front of the loaded ICRH antenna ("pump-out" effect) is demonstrated by Langmuir probe measurements in a low recycling regime. An up�down asymmetry in the heat-flux and in the antenna erosion is also observed, and is associated with poloidal variations of the local density. These density redistributions are ascribed to an E×B convection process linked with rf sheaths. To assess this interpretation, the 2D transport code CELLS for modelling the density distribution near an ICRH antenna was developed and described in this paper. The code takes into account perpendicular diffusion, parallel transport and convection in rf-sheath-driven potentials. The strong density differences obtained in simulations reproduce up�down asymmetries of the heat fluxes.
Bibliographic Reference: An article published in: Physics of Plasmas, June 2002, Volume 9, Issue 6, pp. 2619-2632
Availability: This article can be accessed online by subscribers, and can be ordered online by non-subscribers, at: http://dx.doi.org/10.1063/1.1472501
Record Number: 200215618 / Last updated on: 2002-12-02
Original language: en
Available languages: en