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Abstract

Fast-wave transit-time magnetic-pumping (TTMP) current drive efficiency calculations using ray tracing techniques are presented, using A2-antennae for the experiments, carried out in the divertor phase of the extended JET programme. The antenna plasma coupling problem is properly solved using a full wave solution which makes it possible to incorporate the antenna array directivity and full asymmetric spectrum in the calculations. Current drive calculations at each step of the ray take into account the power deposition profile and the electron trapping effects correctly. The poloidal field effects which change k(parallel), and therefore have important consequences on the current drive efficiencies, are also taken into account. It is shown that a current drive efficiency factor of 0.11 in units of 1.0 E20 W/A/m2 is obtained for an electron temperature of 10 keV. Synergistic effects between the ICRH and the lower hybrid current drive system in which a population of fast electrons is produced are also evaluated. It is found that a 0.5% concentration of 200 keV fast electrons would increase the current drive efficiency by 35% at a toroidal mode number n = 11 and this increase could be as large as a factor of 2 at lower n values in the range 2 to 4.

Additional information

Authors: BHATNAGAR V P, JET Joint Undertaking, Abingdon, Oxon. (GB);JACQUINOT J, JET Joint Undertaking, Abingdon, Oxon. (GB);START D F H, JET Joint Undertaking, Abingdon, Oxon. (GB)
Bibliographic Reference: Report: JET-P(91)41 EN (1991) 13 pp.
Availability: Available from the Publications Officer, JET Joint Undertaking, Abingdon, Oxon. OX14 3EA (GB)
Record Number: 199210158 / Last updated on: 1994-12-02
Category: PUBLICATION
Original language: en
Available languages: en