A high-density gas jet supersonic nozzle is reported in this paper.The jitter andactuation time of the nozzle is determined by the pin discharge and laser spark radiation respec-tively.The jitter time of the nozzle is within 10 μs with the backing pressure as high as 25 bar.With a nanosecond laser pulse focused on the gas jet about 1 mm below the nozzle,the actuationtime is calculated to be about 15 ms by detecting the laser produced spark radiation,which revealsthe existence of the gas jet and the relative gas density evolving with time.Consequently the gasdensity is estimated to be well above 10^(19) cm^(-3),compared with theoretical simulations from thenozzle parameters.
Interactions of oblique incident probe wave with oncoming ionization fronts havebeen investigated using moving boundary conditions. Field conversion coefficients of reflection,transmission and magnetic modes produced in the interactions are derived. Phase matchingconditions at the front and frequency up-shifting formulas for the three modes are also presented.
