MHD Modes Driven by Strong ExB Velocity Shear in Tokamaks
It is theoretically shown that a strong shear of the ExB velocity can drive electromagnetic instabilities in tokamak plasmas. The instability threshold is determined by the condition, for finite values of the magnetic shear. The Alfven velocity, with the safety factor and the major radius of the tokamak. The Mercier modes are considered as an example of instabilities driven by the velocity and shear of this velocity on the Mercier modes are analyzed. A set of MHD equations for a numerical analysis of the ExB velocity shear effect on drift-MHD modes is derived. The theoretically obtained threshold is compared with conditions in JET shear-optimized discharges.
Bibliographic Reference: Report: JET-P(99)26, 19pp.
Availability: Available from the Librarian, JET Laboratory, Abingdon (GB)
Record Number: 199911463 / Last updated on: 1999-10-08
Original language: en
Available languages: en