Sustained Fully Non-Inductive Scenarios Using Pressure and Current profile Control with ECCD
The Ecw system on TCv allows the study of a wide range of poloidal and toroidal launch angles. Both Ech and ECCD experiments have been performed to demonstrate the modification of the electron temperature and current profiles. In particular a multi-channel hard X-ray camera clearly shows the generation of high energy electron tail which increases with increasing toroidal launch angle. Using a scenario with three 0.5mW gyrotrons providing on-axis CO-CD, we have obtained full current replacement of 150kA. However, this leads to very peaked profiles which ar MHD unstable and the discharge disrupts. By careful distribution of the power deposition and current source profiles over the minor radius we have obtained steady-state scenarios up to 124kA with Te0=3.5KeV and ne=10(19)m(-3). These scenarios are sustained for 1.9s, that is, more than 400 confinement times and more than 10 current redistribution times. Therefore, both the pressure and current profiles are sustained by the 1.5MW of ECCD power. By lowering the feedback plasma current demand, the ohmic transformer is recharged; this provides a very good diagnostic of the total non-inductive current driven in these scenarios.
Bibliographic Reference: Paper presented: IAEA Technical Committee meeting on ECRH Physics and Technology for Fusion devices and EC-11, Oh-ari (JP), 4-8th October (1999)
Availability: Available from Librarian, Centre de Recherches en Physique des Plasmas, EPF, Lausanne (CH)
ISBN: ISSN 0458-5895
Record Number: 199911518 / Last updated on: 1999-10-29
Original language: en
Available languages: en