Experimental Studies of L Shell X-Ray Emission from High Density Plasmas.
Abstract
The emission spectrum of krypton ionized into the L shell is experimentally studied in a high density plasma discharge. Theoretical calculations are presented which predict the occurrence of electron density dependent effects on the spectrum due to multiple collisions between excited states in the density range produced in these discharges. The high temperature plasma was transiently formed for 2 to 10 nanoseconds in fast linear z-pinch devices at powers ranging from 5 x 10('9) watts to 5 x 10('12) watts by electromagnetic implosion of a column of krypton gas. The gas was seeded with small quantities of argon and phosphene impurities to produce K shell emission lines which were used to diagnose the plasma. The krypton radiation was analyzed using time resolved bent crystal x-ray spectrometers and x-ray framing cameras, and time integrated bent crystal x-ray spectrometers and grazing incidence XUV spectrometers. These were used to identify a large number (over 100) of previously unidentified or unobserved lines in Kr XXIV through Kr XXIX. The results of the experiment show that experimental charge state distributions of ionized krypton and the experimentally measured relative intensities of the resonance lines of Kr XXVII, both of which are predicted to depend strongly on electron density near 10('20) el/cm('3), agree qualitatively with theory. The high electron density of the krypton plasma causes the production of neon-like Kr XXVII ions at relatively low temperatures. This results in the presence of temperature sensitive sodium-like satellite features in the emission spectrum that also agree with simple theoretical models. Experimental evidence is found for the production of significant population inversions for XUV transitions near 150 angstroms in these high density discharges.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- 1985
- Bibcode:
- 1985PhDT........28S
- Keywords:
-
- Physics: Atomic;
- Dense Plasmas;
- Emission Spectra;
- Ions;
- Krypton;
- Plasma Jets;
- Electron Density (Concentration);
- Plasma Diagnostics;
- Spectroscopic Analysis;
- Ultraviolet Spectrometers;
- X Ray Spectroscopy;
- Plasma Physics