Transit-time method of optical stochastic cooling

In Ref. [1] the utilization of a broadband optical amplifier was proposed for the stochastic cooling process in order to enhance the ultimate possibilities of the conventional microwave stochastic cooling technique [2]. It was shown that the radiation of a particle in a quadrupole wiggler can be amplified and applied back to the same particle in a dipole wiggler, producing therein an energy kick in proportion to the particle's transverse position in the quadrupole wiggler. It was also shown that this scheme is capable of providing damping for both transverse and longitudinal oscillations, but that cooling takes place only in the case of a small beam exnittance & 10 m. We show how to avoid this limitation by using a difFerent approach.