Gauss 3D Space Charge Pusher #1127
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Add the new Gauss 3D space charge pusher.
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ax3l
added
component: space charge
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- replace with new file name in doc - move into own section in CMake
ax3l
reviewed
Sep 17, 2025
| amrex::ParticleReal & AMREX_RESTRICT pz = part_pz[i]; | ||
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| //field integrals from a 3D Gaussian bunch | ||
| int const nint = 401; |
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For the integration, do you want to make the integration steps nint user configurable or is 401 a generally good number for everything?
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Tested and its a bit slow. We probably want to relax the default value a bit and expose it to the user.
| * ``"Gauss3D"`: Calculate 3D space charge forces as if the beam was a Gaussian distribution. | ||
| This model is supported only in particle tracking mode (when ``algo.track = "particles"``). | ||
| Ref.: J. Qiang et al., "Two-and-a-half dimensional symplectic space-charge solver", LBNL Report Number: LBNL-2001674 (2025). |
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Do you already have a link / DOI for the paper? I cannot find it on google scholar yet.
ax3l
reviewed
Sep 17, 2025
ax3l
reviewed
Sep 17, 2025
cemitch99
reviewed
Sep 18, 2025
cemitch99
reviewed
Sep 18, 2025
- avoid temporary arrays - integrate in one go
Only used for particles. Ref orbit asserts well, too.
ax3l
approved these changes
Sep 18, 2025
cemitch99
reviewed
Sep 18, 2025
cemitch99
reviewed
Sep 18, 2025
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This looks ready to me. I will do a follow-up adding another example or two. |
ax3l
reviewed
Oct 7, 2025
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| pintex = sum0ex / 3_prt; | ||
| pintey = sum0ey / 3_prt; | ||
| pintez = sum0ez / 3_prt; |
ax3l
reviewed
Oct 7, 2025
Comment on lines
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| amrex::ParticleReal const push_consts = dt * charge * inv_gamma2 / pz_ref_SI | ||
| * 2_prt * asp * (sigx * sigx * sigz * std::sqrt(2_prt * pi)) | ||
| * bchchg * rfpiepslon; |
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These need a separate constant per x,y,z, which I accidentally removed when refactoring.
Fixed in #1168
This was referenced Oct 7, 2025
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add SC kicks from a 3D Gaussian density distribution.
Checklist
Follow-Up PRs
nintparameter and pick a good (fast and precise enough) default (e.g., 50? 100?)