Theoretical modeling of a gas-puff z-pinch experiment

The authors present theoretical and computational results of the modeling of the CO2 gas-puff Z-pinch experiment at the Weizmann Institute of Science. Experimental data of the motion of the plasma column (pinch radius vs. time) were taken from a visible light framing camera and are in excellent agreement with a zero-dimensional slug model. The pinch velocity vs. time was determined from time-resolved doppler shift measurements of the spectral lines emitted by ions of all charge states. Agreement is very good, until deviations occur at late implosion times. Experimental measurements of electron temperature vs. radius are in agreement with a theoretical model including thermal conduction and Joule heating. A one-dimensional Lagrangian fluid code has been developed to model the collapse. The authors have developed the capability to analyze line emissions from atoms and ions which account for collisional excitation, de-excitation, ionization (including removal of a few electrons by one impact, and ionization into excited states), three-body, radiative, and dielectronic recombination, spontaneous and induced radiative transitions, and self-absorption into surrounding plasma. Their atomic physics codes allow for modeling of non-maxwellian electron energy distributions, as is required for these studies. The kinetic algorithms will be coupled with their 1-D fluid code in order to model the final implosion phase of the plasma, energy flow in the system, and the plasma transport properties