A LONG PULSE, HIGH POWER SOLID-STATE GYROTRON MODULATOR

THIS PROJECT IS TO DEVELOP A LONG PULSE, HIGH POWER SOLID-STATE GYROTRON OR NEUTRAL BEAM MODULATOR SYSTEM. THE SERIES-PASS MODULATOR WILL BE CAPABLE OF OPENING AND CLOSINGCIRCUITS CARRYING TENS TO HUNDREDS OF AMPERES AT HUNDREDS OF KILOVOLTS, AND EVEN MEGAVOLTS, AT SUBMICROSECOND SPEED. THE COMPARATIVELY LOW COST, COMPACT, RUGGED, AND MAINTENANCE-FREE MODULATOR WILL REQUIRE VERY LOW STANDBY POWER AND HAVE A LOW VOLTAGE DROP UNDER CONTINUOUS WAVE HIGHCURRENT CONDITIONS. IN THE APPROACH TAKEN, THE SWITCH SYSTEM IS CURRENT LIMITING AND FAULT TOLERANT AND THUS DOES NOT REQUIRE CROWBAR PROTECTION. IN ADDITION, THE MODULATOR IS INHERENTLY VOLTAGE TRANSIENT PROTECTED AND THUS IS COMPATIBLE EVEN WITH INDUCTIVE CIRCUITS AND FAULT-PRONE LOADS. PREVIOUS RESEARCH AND DEVELOPMENT IDENTIFIED SEVERALKEY TECHNICAL PROBLEMS THAT MUST BE ADDRESSED. PHASE I OF THIS PROJECT IS INVESTIGATING PROBLEMS OF GATE DRIVE POWER DERIVED FROM THE COLLECTOR, FAST ON-BOARD CURRENT MONITORINGAND LIMITING, AND LONG PULSE RELIABILITY AT THE DISSIPATIVE ELEMENTS. HIGH CURRENT AND LONG PULSE LIFE TESTING OF THE DISSIPATIVE ELEMENTS IS ALSO BEING PERFORMED.