Ionization Energy and Level Shift of Multiply

Plasmas with multiply charged ions are of great importance for many applications as, e.g., near-electrode phenomena in arcs, pulsed high-current dis­ charges, plasmas produced by wire explosions, shock fronts, high-intensity lasers and ion beams. Let us mention also that the development of X-ray lasers is closely connected with the behaviour of highly ionized plasmas of heavy elements. Most of the existing stud­ ies of nonideality effects in many-component plasmas have been restricted so far to ions carrying one protonic charge only [1 -4]. There are, however, also first approaches to develop a theory for plasma systems with arbitrary charges [5-9]. Considering plasmas which contain ions of charge ( + Ze), we are expecting that the interactions of these ions increase with Z. Therefore multiply charged ions may give rise to strong nonideality effects [7, 8]. Here we are especially concerned with the influence of nonideality on the ionization energy, which is a key quan­ tity for the ionization kinetics [10, 11], and with the shifts of the energy levels, which are fundamental for the problems of optical transitions [12, 13].