Particle acceleration in a non-uniform HF field

Longitudinal particle motion in an accelerating channel with the strong transversal non-uniformity of a high frequency field is considered. A possibility for providing stable particle acceleration in such channel at the expense of increasing a synchronous phase is analytically based. It is shown that with increasing particle energy the synchronous phase can be smoothly enhanced bringing it to common values (approximately -37 deg). The aperture size increase three times results in increasing the accelerator length approximately by 25 %