Electromagnetic wave excitation by a modulated electron beam injected in an anisotropic plasma channel

A study is made of electromagnetic radiation from a thin modulated electron beam of finite length injected parallel to an external magnetic field in a magnetic-field-aligned cylindrical plasma channel immersed in a uniform ambient magnetoplasma. A rigorous solution for the beam-excited field is obtained and the power lost by the beam in the presence of the channel is examined. A significant difference between the features of whistler wave emission in the presence of a channel and in the case of a homogeneous unbounded plasma is revealed. Estimates of the power emitted in the whistler frequency band are given for a representative example of an artificial plasma channel with enhanced density in a plasma modeled upon the Earth´s ionosphere