Probable sources of a noise in crossed-field devices II. Generating tubes

For pt.I, see ibid., vol.0, no.0, p. 246-7 (2003). The paper deals with one of probable sources of noise that is the rotating convective clouds of space charge. The shapes and structures are similar to ones of the true solutions in a magnetron diode. There are two kinds of convective clouds: (1) periodically breaking away from the electron hub and moving to the anode across the interaction space ones; (2) stable clouds at tops of the electron spokes. In a magnetron a stochastic breaking of the clouds away from the hub takes place. In amplitrons the stable convective clouds occur for the most of the tubes in wide range of output powers and anode voltages. In some cases, the secondary-emission bunches can periodically disturb an electron spokes formation process even in power amplitrons with the cold cathode. It results in decrease of the output amplitude and rise of noise background around a signal peak of the output spectrum. The paper also presents some of the results obtained for two S-band 1MW pulse amplitrons of identical constructions, but with differing cathodes.