Mathematical particle tracing: Diffuse scattering wall condition

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Robert Golub

Robert Golub

May 3, 2013 1:37am UTC

Mathematical particle tracing: Diffuse scattering wall condition

In Comsol 4.3a the diffuse scattering boundary condition is incorrect. it generates an angular distribution with respect to the surface normal of cos(theta), while the correct distribution is cos(theta)*sin(theta). In equation view you see that theta is is chosen by
theta = acos(0.5+random(xxx))
the correct expression is
theta=acos(sqrt(0.5+random(xxx)))
see J. Greenwood, Vacuum 67 (2002) 217–222
Comsol support showed me how to fix this in equation view. The original expression is incompatible with detailed balance

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Ivar Kjelberg

Ivar Kjelberg

May 3, 2013 4:48am UTC in response to Robert Golub

Re: Mathematical particle tracing: Diffuse scattering wall condition

Hi

thanks for reporting this to us out here ;) so long COMSOL has been informed to fix this for next release, the most important have been done

--
Having fun COMSOLing
Ivar

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