Spectroscopic study of soft X-ray sources generated in a plasma focus with neon gas puffing

Soft X-ray emitting spots (hot spots) generated in a plasma focus with a gas puffing are investigated using a streak mode imaging system for the soft X-ray region and a convex Bragg spectrometer which enables time resolved measurement. Using the imaging system, the typical size and lifetime of the hot spots in the focused neon plasma were measured to be similar to 1 mm in diameter, 13 mm in length and with a 5 similar to 8 ns lifetime, approximately. The full width at half-maximum of the duration of the NeX (12.19 Angstrom) 1s-2p and NeIX (13.447 Angstrom) 1s(2)-1s2p lines measured with the spectrometer agree with that measured with the imaging system. The soft X-ray emission started in the latter half of the plasma sustaining time measured by visible streak image and extinguished almost at the same time as the visible image. In the case of neon plasma; generation of the soft X-rays is not ascribed to the disruption of the plasma column, but to the growth of the macroscopic instabilities in the plasma column. After the disruption, the soft X-rays are not observed at all. The electron temperature and the density of the hot spots were estimated by several methods giving similar to 0.5 keV and in order of 10(21)/cm(3), respectively.