MHD Activity in GOL-3 During Injection of Long-Pulse Electron Beam

Magnetic activity of plasma during the injection of 2-8 MW non-relativistic electron beam of sub-millisecond duration in GOL-3 is studied.

The main parameters of fluctuations of the magnetic field are discussed. In most experiments the m = 1 azimuthal mode has the largest value, although, higher modes stay significant. Amplitude of the largest perturbations is ~1/2 of the beam radius. The phase grows monotonically, rotational velocity agrees well with the expected E×B drift.

Longitudinal velocity of the fluctuations was also measured, its value v ~ 10⁷ cm/s is close to the ion sound speed for T_e ~ 100 eV.