A Quick Start of High Current Discharge from a Cold LAB6 Cathode for Neutral Beam Injection

摘要

A cathode system with a high current density, long life, fast rise time at discharge, and mechanical simplicity is described for use in the fast neutral beam injection of thermonuclear fusion. A cold LaB6 cathode with a large heat capacity can be used for a high current discharge which needs a fast rise time (below 0.1 sec) if the discharge is fired twice in series. The temperature decay of the cathode after the first discharge held to a very slow rise time to protect the cathode) is very slow. The second discharge rises up quickly due to remaining heat and the effective plasma confinement in the cathode system even if a time interval between in the first and the second is near 30 sec.