Creation and control of variably shaped plasmas in TCV

Abstract

During the first year of operation, the TCV tokamak has produced a large variety of plasma shapes and magnetic configurations, with 1.0<or=Btor<or=1.46 T, Ip<or=800 kA, kappa <or=2.05, -0.7<or= delta <or=0.7. A new shape control algorithm, based on finite element reconstruction of the plasma current in real time, has been implemented. Vertical growth rates of 800 sec-1 corresponding to a stability margin f=1.15, have been stabilized. Ohmic H-modes, with energy confinement times reaching 80 ms, normalized beta ( beta toraB/Ip) of 1.9 and tau E/ITER89-P of 2.4 have been obtained in single-null X-point deuterium discharges with the ion grad B drift towards the X-point. Limiter H-modes with maximum line averaged electron densities of 1.7*1020m-3 have been observed in D-shaped plasmas with 360 kA<or=Ip<or=600 kA.