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20 2.4 2.8 Alpha particle energy(Mev)

Fig. I Alpha particle spectrum

REFERENCES: 1. Goldman, E.B., LFFP Report No. 16, University of Rochester, Rochester, N.Y. , 1973. 2. Brueckner, K.A. and Jorna, S., Rev. Mod. Phys. _46, 325 (1974)

CALCULATION OF THE MEAN FREE PATH OF X-RAY RADIATION IN HOT ALUMINUM PLASMA D. Salzmann

A computer program was written for the calculation of the mean free path of X-ray radiation in hot dense aluminum plasma as a function of electron temperature and ion density. The absorbing effects included are the photo­ electric effect and the inverse bremsstrahlung. The latter is negligibly small except at low photon energies and electron temperatures.

In the calculation of the total photoelectric effect, the distribution of the various charge states for a given temperature and density, and the absorption by the K and L electrons of each charge state are taken into account. The reduction in absorption cross section due to the excitation of - 59 -

electrons to higher states is also calculated. The necessary data, such as charge state distribution, electron density, etc. are taken from calculations of another computer code XRAY.

Preliminary results indicate that in an aluminum plasma with an ion 22 -3 density of 10 cm and 100 u diameter, more than 50% of the X-ray energy escapes from the pellet at electron temperatures above 120 eV.

CALCULATION OF X-RAY PRODUCTION RATE AND IONIZATION STATE DENSITY IN HOT ALUMINUM PLASMA* D. Salzmann

A computer program (XRAY) was written to study the ionization state density and radiation rate from hot dense plasmas. The plasma is assumed to be homogeneous and isotropic with constant temperature and ion number density. Since reabsorption is not incorporated, the results refer to the production of X-rays rather than emission from practical plasmas.

The results at present refer to aluminum plasmas only, but the code is general enough also to treat other elements, for which a complete set of atomic data is available. We hope to extend our calculations to elements other than aluminum and study the Z-dependence of the X-ray radiation.

The main aim of the program was to make an off-line study of a simplified problem of X-ray radiation. In order to apply these results to our SUPER one-dimensional hydrodynamic code, we have written the final results of XRAY on the computer magnetic disc and SUPER simply reads in the results (and inter­ polations) rather than repeat the full calculations. This procedure saves computation time and allows calculations with reasonable accuracy.

The program calculates the following quantities as a function of electron temperature and total ion number density: distribution of the charge states, average charge, average ionization energy, free-free radiation, free-bound recombination spectrum, total free-bound radiation rate, line spectrum from various charge states, and total line radiation rate.

This work is partially supported by the U.S. - Israel Binational Science Foundation, Jerusalem