Nanosecond X-radiation pulse generation in long implosion systems with hollow cathode

The system proposed permits to obtain a nanosecond high power radiation pulse using a long pulse current with rise time of ∼ 1 ms for HEDP and ICF research. The main idea of this system is to drive away a current through the outer shell and after that fast transfer the current onto Z-pinch load (liner) with low density plasma of the outer shell due to its geometrical expansion into a hole in the cathode and falling on the inner liner (Fig.). Computational simulations with detailed dynamics of the low density turbulent plasma were performed using the 2-D RMHD code ZETA. The modelling of the implosion of the tungsten double shell under action of 5MA current pulse with 15s rise time was performed. The geometry with the hollow cathode is tested and compared with conventional planar electrode geometry simulation results. Due to long time of implosion and Rayleigh-Taylor instability development a half height radiation pulse duration is of 70ns with radiation power value of 0.3TW for planar electrodes. But for the hollow cathode geometry a radiation pulse rise time is much less and equals to 10ns. The radiation power increases up to 1.2TW. Obtained results shows a possibility to sharp the radiation power of the pinch with hollow cathode and to get nanosecond X-radiation pulse in a long implosion system.