A 3D radiative transfer framework

III. Periodic boundary conditions

¹ Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg, Germany e-mail: yeti@hs.uni-hamburg.de
² Dept. of Physics and Astronomy, University of Oklahoma, 440 W. Brooks, Rm 100, Norman, OK 73019, USA e-mail: baron@ou.edu
³ Computational Research Division, Lawrence Berkeley National Laboratory, MS 50F-1650, 1 Cyclotron Rd, Berkeley, CA 94720-8139, USA

Received: 22 May 2008
Accepted: 24 July 2008

Abstract

Aims. We present a general method to solve radiative transfer problems including scattering in the continuum as well as in lines in 3D configurations with periodic boundary conditions.

Methods. The scattering problem for line transfer is solved via means of an operator splitting (OS) technique. The formal solution is based on a full characteristics method. The approximate Λ operator is constructed considering nearest neighbors exactly. The code is parallelized over both wavelength and solid angle using the MPI library.

Results. We present the results of several test cases with different values of the thermalization parameter and two choices for the temperature structure. The results are directly compared to 1D plane parallel tests. The 3D results agree very well with the well-tested 1D calculations.

Conclusions. Advances in modern computers will make realistic 3D radiative transfer calculations possible in the near future. Our current code scales to very large numbers of processors, but requires larger memory per processor at high spatial resolution.