Measurements of Wave-Particle Interaction in a Single-Ended Q Machine

A Green‐function technique is used to solve the linearized Vlasov equation for the perturbed ion velocity distribution function, $\mathrm{f(x,\hspace{0.17em}v,\hspace{0.17em}t)}$ , in a case where a short density pulse is released into a plasma. Some characteristic features in the calculated curves are caused by wave‐particle interaction. Experimentally, short density pulses are generated in the plasma in a single‐ended $Q$ machine by application of electrical square pulses to a grid immersed in the plasma column. The perturbed ion velocity distribution function in the density pulse is measured by means of an electrostatic energy analyzer. The features showing the wave‐particle interaction appear in the experimental results.