Generation of stimulated emission from a relativistic beam by magnetized dusty plasma crystals (DPCs)

Micrometer-sized dust particles become highly charged when suspended in a plasma. Because of mutual repulsion and the plasma's weaker radial electric fields (usually produced by physically modifying the lower electrode in a rf chamber), they arrange themselves in a structure known as a plasma crystal. Stimulated emission by an accelerated electron beam propagating through a dusty plasma crystal (DPC), acting as a DPC wiggler, is studied. The period of these structures can be extremely short (of the order of hundreds of micrometers) which leads to the possible reduction in the electron beam energy necessary to produce a shorter wavelength. The laser gain in the low-gain-per-pass limit is calculated for a cold beam embedded in an external magnetic field. Numerical computations of the electron trajectories and small-signal gain are presented. It is shown that the DPC wiggler can provide a simple system with high frequency output and output power at relatively modest energies. In many situations it can be superior to conventional wigglers in beam devices.