Nonlinear effects in the current-voltage characteristic of a low-density Q-machine plasma: II. Related to the electrostatic ion-cyclotron instability

In a single-ended Q-machine the current-voltage characteristic of a small c ollector shows a sudden jump of the current at the onset of the electrostat ic ion-cyclotron instability. This jump was also accompanied by hysteresis. This is explained as an indication that the well known nonlinear potential structures that appear periodically in front of the collector during one c ycle of a high-amplitude electrostatic ion-cyclotron instability, originate from collective effects of excitation and ionization interactions produced in front of the cold plate where accelerated electrons suffer inelastic co llisions with the alkaline vapour present in the plasma column.