LARGE-SCALE PLASMA INSTABILITY IN THE STELLARATOR

In the presence of a large uniform longitudinal magnetic field, an infinitc cylinder of lonized gas confined by a circumferential magnetic field is highly unstable with respect to lateral displacement of the plasma column into a helix of large pitch. The situation is representative of conditions in the Stellarator during pulse heating, if the effects of external coaxial conductors are included and if a perlodicity condition is imposed to simulate the closurc of the Stellarator tube. It is shown that the external conductors have negligible effect, but that due to the periodicity condition the instability cannot occur if the ratlo of tlie plasma current to the confining magnetic field is less than a given critical value which depends only on the geometry of the, Stellarator. (auth). Authors: Kruskal, M D. DOE Contract: AT(30-1)-1238. Subjects: CONFIGURATION; CONFINEMENT; CONTROLLED THERMONUCLEAR PROCESSES; CURRENTS; CYLINDERS; DEFORMATION; GASES; HEATING; IONIZATION; MAGNETIC FIELDS; PLASMA; PULSES; STABILITY; STELLARATORS; THERMONUCLEAR DEVICES