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[WIP] Adding Higginson's correction and a test for the Coulomb collision module
We try to add a test that the simulation result should match better with an analytical solution for the Coulomb collision module. The test is described by Smilei (3. Temperature isotropization, Fig 18.): https://smileipic.github.io/Smilei/Understand/collisions.html#test-cases-for-collisions Their scripts can be found here: https://smileipic.github.io/tutorials/advanced_collisions.html https://github.com/SmileiPIC/Smilei/tree/master/benchmarks/collisions
When implementing the test, we found our Coulomb module has a bug that occurs among collisions within a single species, which should be related to Higginson's correction: https://www.sciencedirect.com/science/article/pii/S0021999120302242?via%3Dihub
Thus, we will add Higginson's correction and that test in this PR.
So far, this version of the PR still has some issues, the results do not match that well.
Smilei's plot:
Ours:
@Yin-YinjianZhao @RemiLehe Would you be able to point to the lines in the Smilei code where the Higginson correction is implemented? Is it supposed to be found somewhere in their file Collisions/BinaryProcesses.cpp?
Yes, the intra-species correction can be found here: https://github.com/SmileiPIC/Smilei/blob/master/src/Collisions/BinaryProcesses.cpp#L304 More broadly, the Higginson scheme itself is implemented throughout this file so it is difficult to point a specific line.
