Study of the Sloshing Ion Formation in a Minimum B Mirror Field

Abstract

As a step towards the creation of a thermal barrier in a tandem mirror, formation of sloshing ion distribution is studied by oblique injection of neutral beams into one of the minimum B mirrors of GAMMA 6. Formation of the sloshing ion distribution is verified from the observations of the pitch angle distribution. The distribution is kept in a quasi-steady state, against relaxation of sloshing ions, to form a broad distribution. Potential dip is also observed in association with the sloshing ion distribution. The potential dip is sustained because the density of cold ions trapped in the dip is small.

Contribution on tandem mirrors at the University of Tsukuba (GAMMA 6 and GAMMA 10)

“…By using Langmuir and emissive probes, a dip in the plasma potential was observed in the region of minimum density of the sloshing ions. This result supports the concept of creating a thermal barrier on the basis of a sloshing-ion distribution [7][8][9]. will be suppressed.…”