Preliminary Experiment on the Plasma Confinement in the Heliotron P Field II.

Abstract

The plasma produced by a coaxial plasma gun is axially injected into a magnetic field having the property of minimum average B. This field is generated by the superposition of an usual mirror field upon the field produced by a current-carrying ring placed on the midplane of the mirror field. The injected plasma after 250μsec from the injection is so quiescent as the density fluctuation of 10-2 or less, though the drift wave instability exists at the plasma periphery, where the density gradient is fairly steep. The frequency spectrum of the instability has a peak at about 22 kHz and its perpendicular wave length is about 2 cm.By inserting a glass cylinder just ins id the ring, above field becomes the Heliotron C type field. The plasma injected into this field is quite noisy and it decays faster than the plasma in the minimum average B field.