Full Paper
IAEA-CN77
Contents Return Previous Page Next Page Index


Return To: Session EXP4 - Current Drive, Heating, Fuelling, Divertors
Prev Page: (EXP4/22) Impurity Radiation Efficiency and Retention in Tore
Next Page: (EXP4/24) Operation of ASDEX Upgrade with High-Z Wall


(EXP4/23) Detachment in Variable Divertor Geometry on TCV

R. A. Pitts1), A. Loarte2), B. P. Duval1), J.-M. Moret1), J. A. Boedo3), D. P. Coster4), J. Horacek5), A. S. Kukushkin6) and the TCV Team1)
 
1) Centre de Recherches en Physique des Plasmas, Association EURATOM-Confédération Suisse, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
2) EFDA-CSU, Max Planck Institut für Plasmaphysik, D-85748 Garching, Germany
3) Fusion Energy Program, University of California, San Diego, CA 92093-0417, USA
4) Max-Plank-Insitut für Plasmaphysik, Boltzmannstr. 2, D-85748, Garching, Germany.
5) IPP, Academy of Sciences of the Czech Republic, Za Slovankou 3, POB 17, 182 21 Praha
6) ITER Joint Central Team, Garching Joint Working Site, Boltzmannstr. 2, D-85748, Garching, Germany.

Abstract.  Although the requirement of shape flexibility in TCV precludes the use of fixed baffle or optimised divertor target structures, it does allow for the investigation of diverted equilibria not possible in more conventional tokamaks. One such single null configuration is simultaneously characterised by a very short inboard poloidal depth from X-point to strike point on a vertical target and an extremely long poloidal depth to a horizontal target on the outboard side. Density ramp discharges leave the inboard target plasma attached even at the highest densities, whilst clear partial detachment is observed at the outboard target. Modeling of this configuration using the B2-Eirene code package shows that the outboard divertor achieves high recycling at very low densities, with the rollover to detachment occurring near the outer strike point very soon after the density ramp begins. An important result of the modeling effort is that, due to the low apparent densities in the TCV outboard divertor, the code cannot quantitatively reproduce the absolute level of observed detachment without artificially increasing fivefold the charged particle sink due to three-body and radiative recombination.

Read the full paper in PDF format.

IAEA 2001