Implementation of Bremsstrahlung collisions #5537
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Source/Particles/Collision/BinaryCollision/Bremsstrahlung/BremsstrahlungFunc.H
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dpgrote
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Since the number of collision is the number of electrons there are some pairs the are not done when the number of species 2 is greater than the number of electrons.
Removed the use of the temporary sigmaC array. Now use quadratic weighting for the photon energy.
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Uses when the calculated cut off is below the default value.
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This gives results that more closely matches the phirad from Seltzer and Berger
Now the ion momentum is also updated
That is based on the electron energy in the center of mass frame. This avoids sqrt of negative when doing momenumt and energy conservation
dpgrote
changed the title
ax3l
reviewed
Feb 19, 2025
| collisions.collision_names = bremsstrahlung | ||
| bremsstrahlung.type = bremsstrahlung | ||
| bremsstrahlung.species = electrons ions | ||
| bremsstrahlung.Z = 5 |
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Is this to overwrite the ionization state or, since this is a particle-particle mode, can we also rely on the charge / ionization state of the ion we collide with?
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The Z is only used to indicate the atomic number, which is used to select which cross section data to use from the tables.
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This PR adds Bremsstrahlung collisions, producing photon particles. It does pair wise collisions between electron and ion species, produce photons. The algorithm conserves momentum and energy.
It uses the cross section tables from Seltzer and Berger, but now only has the cross sections for Z = 1, 2, 5, and 6. A future PR can add individual cross section data as needed or change this to read in data from the warpx-data repo to allow any Z.
Todo: