A LOW COST INDUCTION LINAC FOR HIGH POWER ELECTRON CYCLOTRONHEATING MILLIMETER WAVE SOURCES

AMONG THE VARIOUS AUXILIARY HEATING METHODS FOR TOKAMAK PLASMAS, ELECTRON CYCLOTRON HEATING (ECH) OFFERS MANY ADVANTAGES AND CURRENTLY IS FAVORED AS THE PRIMARY HEATING TECHNIQUE FOR FUTURE TOKAMAK DEVICES (COMPACT IGNITION TOKAMAK AND INTERNATIONAL THERMONUCLEAR EXPERIMENTAL REACTOR). THE ULTIMATE SUCCESS OF ECH AS A METHOD OF AUXILIARY HEATING WILL DEPEND ON THE AVAILABILITY OF ECONOMICAL MILLIMETER-WAVE SOURCES AT THE APPROPRIATE FREQUENCIES (250 TO 600 GHZ) AND POWER LEVELS (1 MW). THE FREE-ELECTRON LASER (FEL) AND THE CYCLOTRON AUTORESONANCE MASER (CARM) ARE BOTH CANDIDATES FOR HIGH POWER TUNABLE ECH RADIATION SOURCES. THESE RADIATION SOURCES RELY ON ACCELERATOR FACILITIES TO PROVIDE HIGH ENERGY (1 TO 10 MEV),HIGH AVERAGE POWER (2 TO 50 MW) ELECTRON BEAMS. CONSEQUENTLY, THE DEVELOPMENT OF ECONOMICAL FELS AND CARMS WILL REQUIRE THE AVAILABILITY OF LOW COST, HIGH EFFICIENCY ACCELERATOR TECHNOLOGY. THE INDUCTION LINAC IS THE ACCELERATOR OF CHOICE FOR DRIVING HIGH POWER MILLIMETER-WAVEDEVICES. IT IS UNIQUE IN ITS CAPABILITY TO ACCELERATE HIGH PEAK CURRENTS (1,000 A) TO SEVERAL MEV WITH A HIGH PULSE REPETITION RATE (1,000 HZ), DELIVERING MULTI-MW ELECTRON-BEAM (E-BEAM) POWER TO THE FEL WIGGLER OR CARM RESONATOR. THIS PROJECT INVOLVES THE DEVELOPMENT OF A HIGH REPETITION RATE (20 KHZ) INDUCTION LINAC FOR DRIVING ECH SOURCES. THE DESIGN WILL USE SILICON CONTROLLED, RECTIFIER COMMUTATED, MAGNETIC PULSE COMPRESSION POWER SYSTEMS IN CONJUNCTION WITH COMPACT ACCELERATOR CELL DESIGNS. THE GOAL IS TO DEVELOP A LOW COST AND HIGHLY RELIABLE ACCELERATOR SUITABLE FOR DRIVING HIGH FREQUENCY (250 GHZ), HIGH POWER (1 MW) MICROWAVE SOURCES FOR ECH APPLICATIONS. A PROTOTYPE ACCELERATOR TO BE CONSTRUCTED IN PHASE II WILL BE INSTALLED IN THE HIGH POWER MICROWAVE LABORATORY AT THE MIT PLASMA FUSION CENTER (OR A LABORATORY OF DOE'S CHOICE) WHERE INITIAL MICROWAVE GENERATION EXPERIMENTS WILL BE CONDUCTED.