The effect of an axial magnetic field （AMF） on an old xenon short-arc lamp is experimentally investigated in this work. As the AMF increases up to 18 roT, the visible radiation power and electric power ascend more than 80% and 70% respectively, and the radiation efficiency is improved by 23% for the best increment at 12 mT AMF. The measurement of radiation intensity shows that the increment of radiation intensity comes mostly from the plasma area close to the cathode tip, and partially from the other area of the arc column. Successive images of the arc indicate that the arc column not only rotates about its axis, but revolves around the axis of electrodes with the AMF. The arc column structure is constricted, distorted and elongated as the AMF increases. It is suggested that the improvements of the radiation intensity and radiation efficiency are attributed to the constriction of the arc column, which is mainly induced by the enhanced cathode jet.
Magnetically dispersed arc plasma exhibits typically dispersed uniform arc column as well as diffusive cathode root and diffusive anode root. In this paper magnetically dispersed arc plasma coupled with solid cathode is numerically simulated by the simplified cathode sheath model of LOWKE . The numerical simulation results in argon show that the maximum value of arc root current density on the cathode surface is 3.5×10^7 A/m^2）, and the maximum value of energy flux on the cathode surface is 3× 10^7 J/m^2, both values are less than the average values of a contracted arc, respectively.
