Electron-beam injection into the ionospheric plasma at an angle to the geomagnetic field

The dynamics of a quasi-stationary electron beam propagating through the ionospheric plasma in the absence of beam-plasma disacharge is investigated theoretically. It is shown that, if the pitch angle of electron injection is greater than a certain specified value, the beam has the form of a Larmor helix, rapidly stretched into a hollow rotating cylinder. If the pitch angle is much smaller than this specified angle, the dynamics resemble that of a beam injected along the geomagnetic field lines.