Speaker
Description
Eddy currents induced by rippling magnets in axially asymmetric vacuum chambers are known to generate magnetic multipoles of higher orders, with a dynamic sextupole driven by a time-varying dipole being a common example. However, the inverse phenomenon—lower-order multipoles created by an oscillating higher-order multipole magnet, though consistent with Maxwell’s equations—has not been explored to our knowledge. In this paper, we present an analytical derivation of the kick for the driving magnetic multipole of any order and the vacuum chamber of arbitrary shape. We then validate our findings using FEM simulations. Finally, we demonstrate the relevance of this effect to the Electron Storage Ring (ESR) of the Electron-Ion Collider. The ESR has very stringent orbit stability requirements at the interaction point, which demand rigorous evaluation of all potential dipolar kick contributions. Our findings reveal that the dipolar kicks generated by rippling sextupoles are sufficiently strong to require the ESR sextupole power supply ripple specification to be tightened from an otherwise sufficient 100 parts per million (ppm) rms to 20 ppm.
Funding Agency
Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
| Region represented | America |
|---|---|
| Paper preparation format | LaTeX |
