Ionization of impurity atoms in a multicomponent laser plasma

The ionization of impurity atoms in a multicomponent laser plasma is studied. A theoretical treatment and experimental data are used to establish that the electron density in the plasma is determined by the constant of the ionization rate of the majority component of the plasma. At moderate intensities the principal mechanism is ionization by electron impact. The ionization rates for the atoms of the different elements can be calculated by means of the Seaton formula. An expression is derived from first principles for calculating the degree of ionization of the atoms, which permits satisfactory agreement between the calculated and experimental values. 20 refs., 5 figs., 2 tabs.