Hi there,(adsbygoogle = window.adsbygoogle || []).push({});

I am currently trying to understand the theoretical frame work of diffusive shock acceleration. I am having trouble understanding a step in the derivation given by drury 1983 (http://www.oa.uj.edu.pl/user/mio/Ast-Wys-En/Literatura/drury.pdf). In the derivation of eq. 2.47 it is stated (just below the equation), that for an isotropic flux the shock crossing probability is proportional to cos(theta) and hence a factor of 2 cos(theta) is needed. I tried to tinker this together by using other literature and googling it a bit but i don't seem to find a satisfying answer for where exactly this comes from. I am sure the solution is rather simple but i don't see it. I would appreciate it if someone could explain it to me or perhaps refer me to a piece of literature where it is better described.

Thx

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# I Shock crossing probability for isotropic particle flux

Have something to add?

Draft saved
Draft deleted

**Physics Forums | Science Articles, Homework Help, Discussion**