Generation of field-reversing electron rings by neutralized-cusp injection into a magnetic mirror trap

Abstract

Space charge effects were virtually eliminated by introducing a background of hydrogen gas to permit charge neutralization as the electron beam transmits the cusp. As a result, a 10-20 kA pulsed beam of 350 keV and 60 nsec has produced circulating electron layers with diamagnetic fields on the mirror axis up to 185 per cent of the vacuum field and lifetimes up to 9.5 mu sec. These electron rings exhibit characteristics very similar to those generated by perpendicular injection.