Steady-state transalfvenic MHD flows in coaxial channels with longitudinal magnetic field

Transalfvenic magnetohydrodynamic (MHD) flows in coaxial channels of plasma accelerators in the presence of a longitudinal magnetic field are considered. Transalfvenic flows are characterized by the transition of a plasma flow through the alfvenic velocity corresponding to the longitudinal field. The main results are obtained for narrow nozzle-type flow tubes of curvilinear geometry in the quasi-one-dimensional approach. The analytical expressions for plasma parameters in the transition point and for its geometric place are presented. The numerical researches of flow regime changing from superalfvenic to subalfvenic in a narrow flow tube of two configuration variants are provided.