Line radiation from a hot, optically thin plasma - Collision strengths and emissivities
T. J. Gaetz, E. E. Salpeter;
ApJS, 1983, 52, 155
ABSTRACT:Theoretical and experimental data are collected for collision strengths of the strongest multiplets between 1 and 3000 A in a hot, optically thin
plasma.
The elements included are H, He, C, N, O, Ne, Mg, Si, S, and Fe.
Simple
power-law fits, as a function of gas-kinetic electron temperature, are provided
for the collision strengths of the strongest multiplets for temperatures
between 40,000 and 100 million K.
The fits are good to about 10 percent for
temperatures within a factor of 3 of the temperature at which the steady-state
equilibrium ion abundance peaks.
The collision strengths for these strong
multiplets are also used to calculate the multiplet emissivities for a plasma
assumed to be in steady-state collisional ionization equilibrium.
The
multiplet emissivities are given for temperatures between 2.5 million and 100
million K.
The total steady-state emissivity (including continuum) and the
emissivities in selected energy bins are also presented.
Note, however, that
steady-state collisional ionization equilibrium is not a good assumption for
shock-heated plasmas for temperatures lower than about three million K.
KEYWORDS: collision rates, emissivity, high temperature plasmas, line spectra, plasma radiation, solar corona, supernova remnants, atomic collisions, cosmic plasma, electron transitions, fine structure, optical thickness, tables (data), temperature dependence
CODE: gaetz83