A HIGH FIELD, HIGH FREQUENCY ELECTRON CYCLOTRON RESONANCE ION SOURCE UTILIZING AN AXISYMMETRIC MAGNETIC FIELD CONFIGURATION

THE OBJECTIVE OF THIS PROJECT IS TO DEVELOP AN INNOVATIVE ION SOURCE THAT PRODUCES HIGHER ION CURRENT AND MORE HIGHLY CHARGED IONS THAN CONVENTIONAL ION SOURCES. AN ELECTRON CYCLOTRON RESONANCE ION SOURCE (ECRIS) PRODUCES IONS BY CREATING A PLASMA IN AN OPEN-ENDED MAGNETIC FIELD (A "MAGNETIC MIRROR") AND HEATING THE ELECTRONS WITH MICROWAVESAT THE ELECTRON CYCLOTRON FREQUENCY. THE HOT ELECTRONS IONIZE NEUTRAL ATOMS, AND THE RESULTING IONS FLOW OUT OF THEPLASMA ALONG THE MAGNETIC FIELD. A CONVENTIONAL ECRIS USES A NONAXISYMMETRIC MAGNETIC MIRROR TO AVOID MAGNETOHYDRODYNAMIC INSTABILITIES THAT WOULD DISRUPT THE PLASMA. HOWEVER, USING AN AXISYMMETRIC MAGNETIC FIELD ALLOWS HIGH FIELD STRENGTH, MAKING POSSIBLE HIGHER PLASMA DENSITIES AND TEMPERATURES, AND HENCE HIGHER ION CURRENT ANDCHARGE STATE. THIS INNOVATION USES AN AXISYMMETRIC MAGNETICFIELD STABILIZED WITH A POPULATION OF VERY HOT (RELATIVISTIC) ELECTRONS, A TECHNIQUE THAT HAS BEEN USED SUCCESSFULLY IN FUSION EXPERIMENTS. NORMALLY, THIS SCHEME WOULD REQUIRE A CERTAIN NNEUTRAL GAS PRESSURE IN ORDER TO PRODUCE THE WARM PLASMA REQUIRED FOR STABILITY OF THE HOT ELECTRONS, BUT THE NEUTRAL GAS WOULD PREVENT THE FORMATION OF HIGHLY CHARGED IONS. THIS PROBLEM IS BEING OVERCOME BY PRODUCING THE WARM PLASMA IN A REGION OF HIGHER NEUTRAL PRESSURE OUTSIDE THE MAGNETIC MIRROR AND ALLOWING IT TO FLOWIN. PHASE I OF THIS PROJECT INVOLVES STUDYING AN ALTERNATIVE APPROACH TO HIGH FREQUENCY, HIGH FIELD ECRIS THAT SUBSTANTIALLY SIMPLIFIES THE MAGNETIC FIELD DESIGN REQUIREMENTS, ALLOWING HIGHER CURRENT AND ION CHARGE STATES THAN ARE OTHERWISE ACHIEBABLE.