Image charge undulator

A relativistic electron beam moving close to periodic grating surfaces may undergo undulating motion due to its image charge wakefields. This motion can be a mechanism for producing hard incoherent or coherent radiation. A new device, an image charge undulator, is proposed to realize this mechanism. We demonstrate the physics principle of this device by a two-dimensional model with an infinitely long uniform sheet current. The new undulator could be employed for constructing a single-pass, high-intensity, compact-size and ultra-short-wavelength light source.