A FEASIBILITY STUDY FOR A 5-MW, 300-GHZ QUASI-OPTICAL GYROTRON

HIGH POWER, CW (CONTINUOUS WAVE) SOURCES AT FREQUENCIES NEAR 300 GHZ ARE NEEDED FOR ELECTRON CYCLOTRON HEATING IN ADVANCED MAGNETIC FUSION DEVICES SUCH AS THE CIT (COMPACT IGNITION TOKAMAK). RECENT DEVELOPMENTS IN GYROTRONS HAVE PUSHED THE STATE OF THE ART TO 100 KW CW AT 140 GHZ. ONE MEGAWATT AT 140 GHZ APPEARS FEASIBLE, BUT NEARTO THE LIMIT OF THE CURRENT FORM OF THE GYROTRON. THE QUASI-OPTICAL GYROTRON IS A NEW FORM OF GYROTRON IN WHICH THE STANDARD MICROWAVE CAVITY IS REPLACED BY A LARGE OPTICAL CAVITY. THE OVERALL CONFIGURATION OF THE DEVICE AND THE LARGE CAVITY ARE SUITABLE IN PRINCIPLE FOR PRODUCTION OF VERY LARGE POWERS. THE PROPOSED STUDY IS TO DETERMINE, THROUGH CALCULATION, THE FEASIBILITY OF A 5-MW CW, 300-GHZ QUASI-OPTICAL GYROTRON. EMPHASIS IS PLACED ON THE STUDY OF ELECTRON BEAM GENERATION AND PROPAGATION AND THE OPTICAL CAVITY, WITH THE GOAL OF REALIZING A PRELIMINARY DESIGN WITH AN EFFICIENCY OF OVER 30%. (THEORY PREDICTS EFFICIENCIES AS HIGH AS 45%.) CONSIDERATION OF NONCIRCULAR GEOMETRIES FOR BOTH THE ELECTRON BEAM AND RESONATOR MIRRORS IS CENTRAL TO THE STUDY.