RESISTIVE EFFECTS IN EXTRAP
Theoretical studies of the resistive equilibrium and stability of an EXTRAP pinch are reported. Extending the previous analysis we reassess properties of the resistive equilibrium in EXTRAP with the emphasis on the time dependence of the latter. We also qualitatively consider the role of resistive instabilities in EXTRAP, showing that the typical timescale of the filamentation of the discharge (i.e. the non-linear development of the tearing instability) is comparable, at present, to the discharge duration. On the other hand, we emphasize that this phenomenon may still be consistent with the experimental observation of the Bennet's equilibrium. The processes of the current start-up and ramp-up are also analyzed for EXTRAP may lead to the compression oscillations around an evolving rather stable equilibrium. The frequency of these oscillations is given. Finally, some consequences of the average minimum-B concept for EXTRAP are discussed and it is shown that this issue virtually reduces to the appearance of the negative curvature of the magnetic field at the periphery. The maximum attainable value of beta at the periphery of the pinch is obtained, as required by the ballooning stability criterion. The influence of the finite resistivity on the ballooning mode is also estimated.
Bibliographic Reference: WRITE TO THE DEPARTMENT OF PLASMA PHYSICS AND FUSION RESEARCH, ROYAL INSTITUTE OF TECHNOLOGY, S-10044 STOCKHOLM (SWEDEN), MENTIONING REPORT TRITA-PFU-85-04, 1985
Record Number: 1989124086800 / Last updated on: 1987-01-01
Available languages: en