Experimental study to accumulate, accelerate and focus a massive plasma beam onto a target

Experimental investigations are presented, where a device similar to a plasma thruster using j×B forces has been used, to accumulate and accelerate a plasma with a mass of about 0.2 mg to beam velocities up to 110 km/s. A pulse line with a capacity of 108 μF was used to provide discharge currents up to 450 kA for a pulse length of 6.5 μs. The discharge vessel consists of a set of coaxial electrodes with a diameter of 5 cm at a length of 50 cm. The total energy efficiency of the plasma acceleration from this process is estimated to be better than 10%. An estimate of the mass of the plasma beam was achieved by measuring the momentum transfer from plasma beam to flyer plates. Using conus-shaped electrodes at the exit of the plasma accelerator a focusing of the plasma to a diameter below 1 cm was achieved.