Waveguide structures for RF undulators with applications to FEL and storage rings

RF undulators, suggested long time ago, has the ad-vantage of fast dynamic control of polarization, undulator strength and wavelength. However, RF undulators require very strong RF fields in order to produce radiation of the same order as conventional static devices. Very high power RF energy confined inside a waveguide or a cavity can pro-vide the necessary RF fields to undulate the electron beam. However, the wall losses in the waveguide should be low enough to make it practically feasible as a CW or quasi CW undulator and, hence, competitive with static devices for applications to storage rings and FELs. Here we present various waveguide structures such as smooth walled and corrugated walled waveguides and various RF modes. We will show that there are some advantages in operating with higher order modes and also with hybrid modes in the cor-rugated guide. We will show that the RF power require-ment for some of these modes will permit a quasi CW op-eration of the undulator, thus permitting its operation in a storage ring