title: Long-pulse improved central electron confinement in the TCV tokamak with electron cyclotron heating and current drive.
abstract: Current profile tailoring by electron cyclotron heating (ECH) and current drive (ECCD) is used to improve central electron energy confinement in the TCV tokamak. Counter-ECCD on axis alone achieves this goal in a transient manner only. A stable scenario is obtained by a two-step sequence of off-axis ECH, which stabilizes magnetohydrodynamics modes, and on-axis counter-ECCD, which generates a flat or inverted current profile. This high-confinement regime, with central temperatures up to 9 keV (at a normalized beta(N) approximately 0.6), has been sustained for the entire duration of the heating pulse, or over 200 electron energy confinement times and 5 current redistribution times.
authors: Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Fédérale de Lausanne, Association EURATOM-Confédération Suisse, CH-1015 Lausanne, Switzerland.
authors: Z A
authors: ZA
authors: Pietrzyk
authors: C
authors: C
authors: Angioni
authors: R
authors: R
authors: Behn
authors: S
authors: S
authors: Coda
authors: T P
authors: TP
authors: Goodman
authors: M A
authors: MA
authors: Henderson
authors: F
authors: F
authors: Hofmann
authors: O
authors: O
authors: Sauter