A microwave inverse Cherenkov accelerator (MICA)

By “inverting” the stimulated Cherenkov effect to stimulated Cherenkov absorption, it is possible to build an electron accelerator device driven by high power microwaves that propagate in a slow-wave TM mode (axial E-field). In this paper, we have solved for the wave dispersion in the structure, found the field distributions, and then used the Lorentz force equations to obtain the motion of a group of electrons distributed in radius and velocity. We find the radial forces are focusing. Electrons in a well-defined filament (r < 0.5 mm) remain collimated and do not strike the dielectric. By using the 15 MW of rf power available at 2.865 GHz, we can accelerate an electron beam (∼6 MeV, few ps pulses) to energy ∼16 MeV. This results in a relatively compact structure that has the advantage of a smooth-bore design and no need of magnetic focusing. The techniques for improving the dielectric breakdown the surface should permit axial fields in the range of 100–200 kV/cm.