Linear analysis of a magnetized plasma loaded helix type slow wave structure

A helix type slow wave structure filled with plasma is immersed in a finite longitudinal magnetic field. Taking into account the effect of the magnetized plasma and the dielectric, the system is separated radially into two regions. By means of sheath model and Maxwell equation, the distribution of the electromagnetic field is established. Using the boundary conditions of each region, the dispersion relation of the slow wave structure is derived. The trend of change for dispersion characteristic and linear gain is analyzed respectively in detail in the cases of various densities of plasma and different strength of the electromagnetic field by numerical computation. Some useful results are obtained on the basis of the discussion.