Advance in diagnostics for high-temperature plasmas based on the analytical result for the ion dynamical broadening of hydrogen spectral lines

It is well known that the ion dynamics is very important for Stark broadeni ng of spectral lines in high-ir plasmas. However, it is usually assumed tha t with the increase of the plasma density N and/or of the principal quantum number n of the upper level of the radiator, the ionic contribution to the impact width (ICIW) tends to zero. In distinction to that paradigm, by fin ding an analytical result for the ion dynamical broadening of hydrogen spec tral lines, we show here that with the increase of N and/or n, the ICIW doe s not decrease. Moreover, for practically important ranges of T, N, and n, this ''residual'' ICIW, being virtually independent of n, can be comparable to the standard electron impact width. This result leads to: (i) a substan tial revision of the past of diagnostic conclusions fora variety of high-ir plasma experiments; (ii) a much better possibility to deduce from experime ntal, Stark-broadened line profiles not only the plasma density but also th e plasma temperature; (iii) a significant enhancement of the accuracy of N and T obtained from experimental line profiles; and (iv) a substantial revi sion of simulation models for the ion dynamical contribution that were base d on a wrong assumption that the latter vanishes under increasing N and/or n. The consequences are especially important for tokamak plasmas, where the diagnostics based on experimental profiles of high Balmer and Paschen line s is frequently used. [S1063-651X(99)50209-2].