ELECTROMAGNETIC PELLET INJECTOR USING A PULSE FORMING LINE

THE STEADY STATE OR LONG PULSE OPERATION OF TOKAMAK REACTORS REQUIRE FUELING OF THE HIGH TEMPERATURE PLASMA BY PELLET INJECTION. IMPROVED PERFORMANCE CAN BE REALIZED IF THE DENSITY PROFILE IS HIGHLY PEAKED IN THE CENTER. TO ACHIEVE SUCH PRECISE SHAPING OF THE DENSITY PROFILE, INJECTION VELOCITIES UP TO 10'S OF KM/SEC MAY BE REQUIRED FOR PELLETS OF A FEW MG IN MASS. PRESENT PELLET INJECTORS BASED ON ACCELERATION BY GAS PRESSURE OR MECHANICAL MEANS ARE CAPABLE OF ATTAINING VELOCITIES OF ONLY ABOUT 2 KM/SEC AND ARE NOT SCALABLE BECAUSE OF FUNDAMENTAL LIMITATIONS. THESE TECHNIQUES ALSO APPLY EXCESSIVE SHOCK TO THE PELLET WHICH CAN CAUSE IT TO FRACTURE. A CONCEPT TO CONTINUOUSLY ACCELERATE PELLETS SUPPORTED BY A SLUG OF HIGH TEMPERATURE SUPERCONDUCTING MATERIAL IN AN ACCELERATOR TUBE BY PROPAGATING A MAGNETIC WAVE IN AN INDUCTOR THAT IS PART OF APULSE FORMING LINE IS PROPOSED. WITH PRESENTLY AVAILABLE HTS MATERIAL, ACCELERATION IN THE 10(4) TO 10(5) G RANGE IS ATTAINABLE. THE G-FORCE IS CONSISTENT WITH THE FRACTURE STRENGTH OF SOLID HYDROGEN. BECAUSE THE ACCELERATION IS CONTINUOUS RATHER THAN AS AN IMPULSE, THE NECESSARY INJECTION VELOCITY CAN BE ATTAINED IN DISTANCES OF ABOUT 10 METERS. DEVELOPMENT OF A PRACTICAL DESIGN BASED ON THIS CONCEPT IS PROPOSED FOR THE PHASE I EFFORT.