Relaxation plasma oscillation in a magnetron diode

Summary form only given, as follows. Low-frequency oscillations (with the frequency in the order of the ion gyrofrequency) in the plasma discharge of a magnetron diode were experimentally found and identified. It was earlier shown theoretically that the gisteresis states might be observed in the systems with charged particle streams. The surplus charge, accumulated due to relaxations by the space charge in such states, were thrown off in the form of current impulses. We researched the gisteresis states in a coaxial discharge placed in an axial magnetic field (dimensions of the electrodes were 10 and 80 mm, the magnetic field strength was (100-1000) Oe, anode voltage was 400 V). The observed oscillations we consider to be stipulated by the periodical accumulation of ions in the central part of the discharge interval of a magnetron diode. The appearance of a low-energy ion stream, registered in the oscillation regime only, confirms our supposition. The possibility of the suppression of oscillations with the help of external magnetic field shear and of the axial cylindrical electron beam was also demonstrated. The influence of these factors leads to a change of the space distribution of the discharge potential interval, therefore the effects of ion trapping and throwing ones off cannot be realized.