HIGH-EFFICIENCY ELECTROTHERMAL ACCELERATOR

Electrothermal accelerators were studied for the purpose of their appl ication for pellet-injection in Tokamaks. Two theoretical models were developed. The first is based on magnetic hydrodynamics equations, the second is based on isobar approximation. Numerical calculations have shown there was a maximum in the curve of the total efficiency versus discharge region length, the value of the maximum being equal to 20% a nd higher. Experimental investigations carried out with the capacitive store element which stores 100 kJ of energy confirmed the theoretical figure for 2-15 g mass projectiles. The value of efficiency defined a s the ratio of projectile kinetic energy to energy deposited into disc harge was about 30%. The drastic drop of the discharge peak current wa s observed, so there is a possibility to increase the aceelerator life time.