Slow-wave electromagnetic instability driven by wiggling relativistic electron beam in ion-channel

The slow-wave electromagnetic (EM) instability excited by a relativistic electron beam (REB) injecting plasmas has been studied using linear electromagnetic hydrodynamic (EMHD) theory. The features of multiple waves propagation are presented. The results of numerical calculation prove that the EM instability occurs in slow-wave band. The necessary and sufficient condition of the EM instability has been found. Both analytic discussion and physical analysis reveal that the electron betatron motion is one of important factors for the EM instability. The physical mechanism of the instability driven by the electron betatron motion has been discussed.