Tungsten wire-array Z pinches at 7–10 MA PTS facility

Experimental results of Z pinches conducted on PTS facility at Institute of Fluid Physics are presented here. Tungsten wire arrays driven by current with peak value of ~7 MA and zero-to-peak rise time of ~100 ns generate an x-ray power of ~50 TW, x-ray energy of ~0.5 MJ and color temperature of ~150 eV. Axial kinetic energy induced by m=0 like instability was proposed to solve the discrepancy that the kinetic energy built up in implosion is too low to contribute to the x-ray radiation. Changes in wavelength of instability in Z pinches might be explained by equivalence of plasma column to plasma waveguide to some extent. The role of magnetic reconnection in corona acceleration and precursor forming in the case of low-wire-number Z pinches has been pointed out. Estimation demonstrates the generation of electromagnetic pulse of 1 GW in peak power and 0.5 J in radiated energy from motion of plasma column with energy conversion efficiency of ~10^-7.