HIGH-BETA OPERATION WITH ENHANCED AXIAL AND RADIAL CONFINEMENT IN THEHIEI TANDEM MIRROR

The operation of a tandem mirror using Ion Cyclotron Range of Frequenc ies (ICRF) waves and limiter biasing is performed in the HIEI tandem m irror. An ion confining potential is formed in the plug cell by high-h eld-side injection of the fast magnetosonic wave. Limiter biasing is s imultaneously imposed with formation of a confining potential and mino rity heating in the central cell, and both axial and radial confinemen t are enhanced by a factor of 4. As a result, a high-beta plasma (simi lar to 14%) is produced in the central cell. The high-beta plasma is s ustained magnetohydrodynamically by ponderomotive force of ICRF electr ic fields.