Modelling the excitation of global Alfvén modes by an external antenna in JETFunded under: FP3-FUSION 11C
The active excitation of global Alfvén modes using the JET saddle coils as the external antenna, provides information on the damping of global modes without the need to drive the modes unstable. For the modelling of the Alfvén mode excitation, the toroidal resistive MHD code CASTOR has been extended to calculate the response to an external antenna. The excitation of a high performance, high beta JET discharge is studied numerically. In particular, the influence of a finite pressure is investigated. Weakly damped low-n global modes do exist in the gaps in the continuous spectrum at high beta. A pressure driven global mode is found due to interaction of Alfvén and slow modes. Its frequency scales solely with the plasma temperature, unlike a pure Alfvén mode with density and magnetic field.
Bibliographic Reference: Report: JET-P(94)49 EN (1994) 16 pp.
Availability: Available from the Publications Officer, JET Joint Undertaking, Abingdon, Oxon. OX14 3EA (GB)
Record Number: 199510238 / Last updated on: 1995-02-21
Original language: en
Available languages: en