Open AccessAccurate free–free Gaunt factors for astrophysical plasmas
Author(s) -
Sutherland Ralph S.
Publication year - 1998
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.1998.01687.x
Subject(s) - physics , extrapolation , plasma , range (aeronautics) , ionization , wavelength , computational physics , statistical physics , theoretical physics , quantum mechanics , ion , statistics , materials science , mathematics , composite material
New calculations of free–free transition matrix element integrals are performed using modern symbolic computing techniques to evaluate the hypergeometric functions with complex arguments. The results are presented in both graphical and tabular form including accurate extrapolation methods. The results are accurate to the level of ∼ 10 −4 , beyond which relativistic corrections would be needed, which are not included. The results are also computed over a very wide range of scaled ionic temperature (γ 2 ) and wavelength, extending earlier results to new regimes encountered in highly photoionized and non‐equilibrium ionization plasmas. These results will be useful in the spectral range from submillimetre to hard X‐ray wavelengths and temperatures from 10 to 10 9 K.