JACoW is a publisher in Geneva, Switzerland that publishes the proceedings of accelerator conferences held around the world by an international collaboration of editors.
@inproceedings{lagniel:ipac2022-mopost038, author = {J.-M. Lagniel}, title = {{Excitation of the σ_{l}_{l} = 90° Resonance by the Cavity RF Accelerating Fields}}, booktitle = {Proc. IPAC'22}, % booktitle = {Proc. 13th International Particle Accelerator Conference (IPAC'22)}, pages = {152--155}, eid = {MOPOST038}, language = {english}, keywords = {resonance, focusing, space-charge, linac, cavity}, venue = {Bangkok, Thailand}, series = {International Particle Accelerator Conference}, number = {13}, publisher = {JACoW Publishing, Geneva, Switzerland}, month = {07}, year = {2022}, issn = {2673-5490}, isbn = {978-3-95450-227-1}, doi = {10.18429/JACoW-IPAC2022-MOPOST038}, url = {https://jacow.org/ipac2022/papers/mopost038.pdf}, abstract = {{In RF linacs the longitudinal focusing is done by nonlinear forces and at high accelerating fields the zero-current longitudinal phase advance per longitudinal focusing period σ₀l_{l} can be high. The nonlinear components of the RF field (sextupolar, octupolar and higher order components) can then excite parametric resonances, including the 4th-order resonance (σ_{l}_{l} = 90°) when σ₀l_{l} is higher than 90°, inducing strong longitudinal emittance growths and acceptance reductions. The longitudinal beam dynamics is therefore complex, even when the nonlinear space-charge forces are ignored. The parametric resonance excitation by the RF field is analyzed before discussing the additional effect of the nonlinear space-charge forces, in particular to explain why the zero-current longitudinal phase advance per transverse focusing period σ₀l_{t} is not a relevant parameter. Examples are given in the SPIRAL2 linac case.}}, }