Multichannel X-ray spectral measurement of hot plasma evolution in nitrogen-puff Z-pinch

Soft x-ray emission from nitrogen plasma of gas-puff Z-pinch device (with energy input 4.3 kJ and current 160 kA) has been studied. Multilayer mirror polychromator with time-resolved registration by PIN diodes was installed and its relatively narrow spectral windows were aligned to the important parts of nitrogen spectrum between 390 and 710 eV. The T_e evolution (≈400 eV in hot spots) was measured from a slope of recomb. continuum of He-like N. The T_e of bulk plasma (≈100 eV) is compared with T_e calculated from yields of K-shell lines. Moreover, pinhole cameras were used for better understanding the radiation phase of the pinch. Time sequences of peaks in x-ray signals corresponding to a number of bright spots on photographs, are presented.