OF RELATIVISTIC-ELECTRON PLASMAS

RELATIVISTIC-ELECTRON PLASMAS, CREATED AND SUSTAINED BY ELECTRON CYCLOTRON HEATING (ECH) IN MAGNETIC- MIRROR FIELDS, HAVE MANY PROMISING APPLICATIONS. THEY CAN BE USED TO STABILIZE PLASMA CONFINEMENT CONFIGURATIONS, SUCH AS THE ELMO BUMPY SQUARE, THE HELIAC, AND EVEN TOKAMAKS; AND THEY CAN ENCHANCE CONFINEMENT IN TANDEM MIRROR DEVICES. THEY MAY ALSO BY USEFUL AS NOVEL SOURCES OF HIGH-POWER MICROWAVE RADIATION. THESE USES OFTEN REQUIRE THAT THE RELATIVISTIC ELECTRONS BE HEATED EFFICIENTLY IN THE PRESENCE OF A DENSE, LOW-TEMPERATURE BACKGROUND PLASMA, AND THAT THE SPATIAL LOCATION AND EXTENT BE CONTROLLED OVER A SIGNIFICANT RANGE. HERE, A NEW APPROACH WILL BE ATTEMPTED FOR ACHIEVING EFFICIENT PREFERENTIAL HEATING OF MILDLY RELATIVISTIC ELECTRONS USING UPPER-OFF-RESONANT POWER INJECTED INTO HIGH-Q STRUCTURES MAINLY IN THE FORM OF ORDINARY MODES. THE ABSORPTION OF THIS POWER CAN BE INTERPRETED IN TERMS OF MODE CONVERSION INTO ELECTRON CYCLOTRON WAVES IN THE ANISOTROPIC, MIRROR CONFINED PLASMA. IN ADDITION, IT IS PLANNED TO USE MULTI-RESONANT ECH POWER TO BREAK UP COHERENT LIMIT CYCLES THAT MIGHT OTHERWISE INHIBIT THE STOCHASTIC HEATING OF MILDLY- RELATIVISTIC ELECTRONS. A SPECIFIC HGIH-Q COUPLING STRUCTURE WILL BE DEFINED IN PHASE I TO IMPLEMENT THE CONCEPT OF A CONVERSION LAYER RESONATOR. THE TECHNICAL FEASIGILITY OF THE APPROACH WILL BE DETERMINED USING SUITABLE GENERALIZATIONS OF EXISTING THEORIES OF MODE-CONVERSION, O-MODE HEAT- ING, AND LIMIT-CYCLE PHENOMENA TO ADAPT THESE THEORIES TO NEAR-TERM APPLICATIONS SUCH AS THE ELMO BUMPY SQUARE AND THE TANDEM MIRROR. A COMBINED EXPERIMENTAL AND ANALYTICAL PROGRAM WILL BE PLANNED TO DEVELOP THE TECHNICAL BASE NEEDED FOR THESE AND LONGER-TERM APPLICATIONS. CONNECTED MAGNETIC MIRRORS OF THE ELMO BUMPY