Study of Fluctuations in the CW Penning Surface-Plasma Source of Negative Ions

Study of current fluctuations for cw Penning SPS with hollow cathode drive was done. The noiseproof measurements of negative ion beam current, current in extracted electrode circuit, discharge current and voltage were carried out by the low‐inductive probes in wide frequency range. Spectrum and intensity of fluctuations at various operation modes, parameters and electrode geometry were recorded for two versions of cw Penning SPS. H− beam current and the extracted electrode circuit current had the level of ripples higher, than the ripples in discharge current and voltage signals. Frequency spectrum of beam and discharge fluctuations displayed stable peaks. The main peak had location in the range 0.1÷1.5 MHz and FWHM of about 0.1 MHz. For the basic operational mode the main peak in frequency spectrum was in the range 0.3–0.4 MHz. The fluctuations of current in extracted electrode circuit and in accelerated electrode circuit had the similar structure and correlated with beam current fluctuations. The obtaine...