Speaker
Description
A model of the beam-beam force for strong-weak simulations has been implemented in the SciBmad library, including variations of the beam size and beam centroid across the interaction region. Similar to models in the Bmad ecosystem, the SciBmad implementation simulates the weak-strong interaction of 6D beam distributions, where only the weak beam becomes non-Gaussian due to single-particle dynamics. Accurate modeling is complicated when strong final focusing varies the strong-beam size along the interaction point, and when crab cavities introduce a sinusoidal centroid shift. To capture these effects, the strong beam is axially subdivided into N equal-charge slices, each treated as a Gaussian distribution. Each weak particle is drifted to the IP center and then sequentially drifted to and kicked by each slice, both transversely and longitudinally, before being drifted back to the IP. To enable high-order nonlinear analysis of the interaction, SciBmad uses the GTPSA.jl truncated power series algebra package. The resulting implementation produces a differentiable phase space map of the interaction that can be evaluated and differentiated to arbitrary order. This map-based formulation is well suited for lattice optimization, machine-learning surrogate modeling, and nonlinear studies including resonance driving term analysis. The nonlinear maps also allow for the analysis of symplecticity of complex beam-beam interactions, in addition to symplectification of beam-beam tracking.
Funding Agency
Department of Energy funding from grant DE-SC0025351
| In which format do you inted to submit your paper? | LaTeX |
|---|