title: Sixth-order resonance of high-intensity linear accelerators.
abstract: It is shown that the sixth-order 6σ=720° (or 6∶2) resonance is manifested for high-intensity beams of linear accelerators through the space charge potential when the depressed phase advance per cell σ is close to and below 120° but no resonance effect is observed for σ above 120°. Simulation studies show a clear emittance growth by this resonance and a characteristic sixfold resonance structure in phase space. To verify that this is a resonance, a frequency analysis was conducted and a study was performed of crossing the resonance from above and from below the resonance. Canonical perturbation is carried out to show that this resonance arises through perturbation of strong 2σ=360° (2∶1) and 4σ=360° (4∶1) space charge resonances. Simulations also show that the space charge 6σ=360° (or 6∶1) resonance is very weak.
authors.affiliation: Institute for Basic Science, Daejeon, Republic of Korea.
authors.forename: Dong-O
authors.initials: DO
authors.lastname: Jeon
authors.affiliation: Department of Physics, Indiana University, Bloomington, Indiana 47405, USA.
authors.forename: Kyung Ryun
authors.initials: KR
authors.lastname: Hwang
authors.affiliation: Institute for Basic Science, Daejeon, Republic of Korea.
authors.forename: Ji-Ho
authors.initials: JH
authors.lastname: Jang
authors.affiliation: Institute for Basic Science, Daejeon, Republic of Korea.
authors.forename: Hyunchang
authors.initials: H
authors.lastname: Jin
authors.affiliation: Institute for Basic Science, Daejeon, Republic of Korea.
authors.forename: Hyojae
authors.initials: H
authors.lastname: Jang