Abstract

Plasma is a natural medium for x-ray third-harmonic generation (THG): the interaction of x-ray laser (XRL) radiation with plasma is similar to that of optical laser radiation with gas or vapor, unless the energy of x-ray quanta E is higher than the ionization potential of the plasma. We consider x-ray THG for couples XRL line-plasma satisfying the following conditions: (i) 2E almost coincides with the energy E_l of some ion level l which is optically inaccessible from the ground level, and (ii) E_l + E is approximately equal to the energy of another level with the large rate of the radiative decay to the ground level. Although the selection of the available XRL lines and the known energy levels of ions is limited, we find and consider (including some propagation conditions) a number of such couples with plasmas of alkalilike ions.

© 1991 Optical Society of America