SLAC, Menlo Park, California, USA
The Microbunched Electron Cooling (MBEC) * is a promising cooling technique that can find applications in future hadron and electron-ion colliders. A 1D model of MBEC has been recently developed in Ref. **. This model predicts the cooling time below two hours for eRHIC 255 GeV proton beams, when two amplification sections are used in the cooling system. In this work, we go beyond the 1D model of Ref. * and develop a realistic 3D theory of MBEC. Our approach is based on the analysis of the dynamics of microscopic 3D fluctuations in the electron and hadron beams during their interaction and propagation through the system. We derive an analytical expression for the cooling rate and optimize it for the parameters of eRHIC. Our analytical results are in reasonable agreement with simulations.
* D. Ratner. Phys. Rev. Lett. 111, 084802 (2013).
** G. Stupakov. PRAB 21, 114402 (2018)
SLAC, Menlo Park, California, USA
Radiation reaction force in a relativistic beam, also known as a CSR wakefield, is often computed using a 1D model of a line charge beam. While this model can serve as a useful tool for a quick calculation, in some cases, it may not be sufficiently accurate. In particular, this model misses the so-called compression effects associated with the change of the electromagnetic energy when the beam is compressed longitudinally or transversely. The existing 3D simulation codes that take this effect into account are often slow and are not easy to use. In this work, we propose a new approach to the calculations of radiation and space charge longitudinal forces based on the use of the integrals for the retarded potentials. Our main result expresses the rate of change of particles energy through 2D (in a 2D model) or 3D integrals for a given orbit of the beam. It generalizes the 1D model and includes the transient effects of at the entrance and the exit from the magnet. For a given beam line with known magnetic lattice, and a known distribution function of the beam, the calculation reduces to taking 2D or 3D integrals along the orbit.
