Coherent Spin Manipulations of a Polarized Beam With a Localized RF Magnetic Field

TL;DR

This paper explores the coherent manipulation of spin in storage rings using localized RF magnetic fields, testing fundamental dynamical principles and confirming conjectures about intrinsic resonance strength.

Contribution

It provides experimental validation of the intrinsic resonance strength concept and analyzes the effects of RF dipoles and betatron oscillations on spin manipulation.

Findings

Confirmation of gauge and Lorentz invariance in spin resonance.

Quantitative analysis of resonance strength dependence on betatron tunes.

Identification of the 'forced' component of resonance strength due to betatron oscillations.

Abstract

The coherent manipulation of spin observables in storage rings provides opportunities to test the application of some fundamental dynamical principles. In this context, it is possible to confirm, using gauge invariance and Lorentz invariance, a conjecture framed by A. M. Kondratenko concerning the "natural" or "intrinsic" resonance strength applicable to a spin rotation from a controlled Froissart-Stora sweep with an RF dipole magnet. The discussion includes a brief treatment of the "forced" component of the resonance strength associated with the effect of the betatron oscillations induced by the operation of the RF diple and a discussion of the effective resonance strength as a function of betatron tunes.