Electron beam as a source of electrostatic waves

This chapter examines the electrostatic instabilities of a radially limited electron beam flowing through a magnetized plasma and discusses some nonlinear consequences of these instabilities. Topics considered include linear stability analysis (high frequency region, low frequency region) and the nonlinear production of low-frequency waves. The experimental injection situation is described by a cold electron beam flowing along the magnetic field lines through a cold magnetized infinite plasma. Radial spreading of the beam due to out-of-axis injection is simulated by changing the beam radius when retaining the same injection conditions (gun voltage and current). It is indicated that in the light of the linear stability analysis, a very high level of high frequency electrostatic turbulence is expected, in the form of both out-of-the-beam radiated waves and of to-the-beam's region-confined solutions