Characterization of a high-power/current pulsed magnetized arc discharge

A high-power pulsed magnetized arc discharge has been developed to allow the superimposition of a dc plasma and a high-power plasma impulse with a single plasma source. A capacitor bank (8400 mu F) is parallel-coupled to the current regulated power supply. The current is transiently increased from its stationary value (200 A) up to 14.5 kA in 650 mu s. The discharge power is thus raised from 18kW to 6.5 MW, corresponding to a power density of up to 1.7x10(12)W m(-3)-10(2) times higher than in the dc mode (200 A). The plasma parameters are measured by Thomson scattering similar to 4 cm downstream of the nozzle. The electron temperature and density vary from similar to 2.6 eV and 7 x 10(20) m(-3) in dc and up to 15 eV and 80 x 10(20) m(-3) during the pulse. A saturation of the electron density with increasing current is observed while the temperature increases monotonically. Time-resolved voltage/current measurements of the arc are used to explain the role of the magnetic field and the evolution of the temperature.

PSI-E