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- Title
Temperature-averaged and total free-free Gaunt factors for κand Maxwellian distributions of electrons.
- Authors
de Avillez, Miguel A.; Breitschwerdt, Dieter
- Abstract
Aims. Optically thin plasmas may deviate from thermal equilibrium and thus, electrons (and ions) are no longer described by the Maxwellian distribution. Instead they can be described by distributions. The free-free spectrum and radiative losses depend on the temperature-averaged (over the electrons distribution) and total Gaunt factors, respectively. Thus, there is a need to calculate and make available these factors to be used by any software that deals with plasma emission. Methods. We recalculated the free-free Gaunt factor for a wide range of energies and frequencies using hypergeometric functions of complex arguments and the Clenshaw recurrence formula technique combined with approximations whenever the difference between the initial and final electron energies is smaller than 10-10 in units of z2Ry. We used double and quadruple precisions. The temperatureaveraged and total Gaunt factors calculations make use of the Gauss-Laguerre integration with 128 nodes. Results. The temperature-averaged and total Gaunt factors depend on the κ parameter, which shows increasing deviations (with respect to the results obtained with the use of the Maxwellian distribution) with decreasing κ. Tables of these Gaunt factors are provided.
- Subjects
PLASMA astrophysics; RELATIVISTIC electrodynamics; THERMODYNAMIC equilibrium; MAXWELL-Boltzmann function; ELECTRON temperature; PLANETARY nebulae
- Publication
Astronomy & Astrophysics / Astronomie et Astrophysique, 2015, Vol 580, p1
- ISSN
0004-6361
- Publication type
Article
- DOI
10.1051/0004-6361/201526104