Whistler excitation by short current pulses in a magnetoplasma

In the frame of laboratory studies devoted to whistler excitation by a modulated electron beam injected in a magnetoplasma under conditions relevant to space experiments, fast processes have been investigated using the modulated electron beam as a train of short-time current pulses injected in the plasma. Single pulses of duration of the order of τ≃15 ns as well as unmodulated beams with sharp fronts (step functions with rise time of the order of τ≃10 ns) have been injected in the afterglow plasma with an energy of the order of 300 eV. Plasma responses to the fast perturbations are transported by whistler waves in the frequency range ωlh≪1/τ