On the radiation MHD modeling of a nanosecond capillary discharge

The dynamics of a nanosecond electrical discharge in a gas-filled (Ar or Xe) capillary with hollow cathode is studied. Mechanisms of plasma heating and radiation generation are examined. 2D simulations are performed in geometry and discharge parameters similar to the experimental ones by means of the radiation-magnetohydrodynamic (R-MHD) code ZETA with spectral and EOS properties calculated in non-LTE approximation by the code THERMOS. A capacitor 0.8 nF charged to 17 kV produces a discharge current with peak amplitude of 4.8 kA. The discharge current executes several damped oscillations with a period of 16 ns. The discharge in Ar generates radiation with many peaks owing to reflections of magnetically induced compression waves in contrast to the emission of the discharge in Xe which corresponds to the current oscillations due to radiative damping of the compression waves. Special attention is paid for the emission within the spectral band 10-15 nm interesting for applications