Experimental studies of thermionic diode-based gridless high-current modulator for space current conversion systems

The paper presents results of experimental studies of a current modulator based on a thermionic diode and intended for use in space systems for current conversion. This device effects current modulation through propagation of plasma structures in the electrode gap and does not require any use of external forces. Such structures are formed through propagation of electronic instability in plasma. Experiments conducted in a Knudsen diode with a Cs-Ba filling demonstrated the feasibility of full modulation of current at burning voltage of 5.6 V and discharge current density of ~10 A/cm2. With electrode gap 0,2...2,0 mm wide, a stable modulation of current and voltage with frequencies of 5.20 kHz and complete current cut-off existed at Cs pressures ranging from 1,5-10-3 to 3,5-10-3 mm Hg. It was discovered that the modulation process can be controlled using additional external forces (auxiliary discharge, electric and magnetic fields), which seems to hold promise for expanding the range of parameters and functionality of the diode modulator.