Rainer Wehrse

We don’t have enough information about this author to calculate their statistics. If you think this is an error let us know.
Learn More
We present a new implicit numerical algorithm for the calculation of the time dependent non-Local Thermodynamic Equilibrium of a gas in an external radiation field that is accurate, fast and unconditionally stable for all spatial and temporal increments. The method is presented as a backward difference scheme in 1-D but can be readily generalised to 3-D. We(More)
This paper presents a continuous finite element method for solving the resonance line transfer problem in moving media. The algorithm is capable of dealing with three spatial dimensions, using hierarchically structured grids which are locally refined by means of duality-based a-posteriori error estimates. Application of the method to coherent isotropic(More)
An analytical solution of the comoving frame radiative transfer equation for a differentiallymoving slab is obtained and written in terms of the wavelength-integrated extinction coefficient ψ, the spectral thickness. It is shown that ψ is much smoother than the extinction coefficient χ(λ) itself and that it can bewell approximated e.g. by a simple piecewise(More)
The general formulae for radiative quantities in the diffusion limit for a differentially moving 3D medium which have been derived in Paper I of this series, are evaluated for the limiting cases of very large and very small velocity gradients |w|. The extinction coefficient is specified by the continuum and the contribution of spectral lines which is(More)
Based on the well known solution of the timeindependent radiative transfer equation along a ray and on suitable point transformations, general quadrature solutions of the monochromatic transfer equation for plane-parallel, spherically-symmetric and arbitrarily shaped 3D configurations with differential motion are derived for the observer’s and the comoving(More)
  • 1