PLASMA CONTAINMENT SCHEME FOR HIGH THRUST DENSITY ION ENGINES

PRESENT ION ENGINE TECHNOLOGY IS LIMITED IN ENGINE THRUST DENSITY AND EFFICIENCY BY ENERGY EXPENSIVE PLASMA PRODUCTION PROCESSES AND BY ION ACCELERATOR SYSTEM DESIGNS WHICH LIMIT THE ATTAINABLE BEAM CURRENT DENSITY. IN ADDITION, NO EFFORTS HAVE BEEN MADE TO ENHANCE THE BASIC LOW OPERATING TEMPERATURE POTENTIAL OF THE ENGINE CONCEPT TO CREATE ANENGINE DESIGN WITH LITTLE OR NO INFRARED SIGNATURE. CONVENTIONAL ION ENGINE ACCELERATOR SYSTEMS CANNOT PROVIDE BOTH HIGH BEAM CURRENTS AND HIGH BEAM ENERGY AND A NEW APPROACH IS REQUIRED. PROOF-OF-PRINCIPLE TESTS ARE BEING PERFORMED ON A LOW LOSS PLASMA CONTAINMENT CONCEPT THAT MAY BE SUITABLE FOR HIGH EFFICIENCY DISCHARGE CHAMBER OPERATION IN A 50 KW ELECTRIC PROPULSION ENGINE BASED ON THE ELECTROSTATIC ION ACCELERATION PROCESS. THIS PLASMA CONTAINMENT CONCEPT IS NOT ANTICIPATED TO BE SUBJECT TO THE NORMAL ION AND ELECTRON LOSS CHARACTERISTICS. ION FLUX LEVELS CAPABLE OF SUPPORTING UP TO A 50 AMPERE ION BEAM ARE BEING ESTABLISHED USING THIS PLASMA CONTAINMENT SCHEME FOR TEST PERIODS OF UP TO SEVERAL HOURS. AN ION ACCELERATOR SYSTEM CAPABLE OF PROVIDING HIGH THRUST DENSITY AND HIGH SPECIFIC IMPULSE IS BEING DESIGNED TO MATE TO THIS DISCHARGE CHAMBER. THIS ACCELERATOR SYSTEM INCORPORATES DESIGN FEATURES WHICH ARE EXPECTED TO ELIMINATE ELECTRODE GAP CHANGES UNDER HIGH BEAM POWER CONDITIONS.