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1.3 PHYSICAL SCIENCES
A new cathode system, consisting of two concentric spherical hollow grids with two aligned orifices, is investigated by space-resolved Langmuir probe measurements and non-linear dynamics analysis. Negative biases of this spherical hollow grids arrangement lead to the formation of two complex space charge structures in the regions of the orifices. The overall dynamics of the current-voltage characteristic (I–V characteristic) of each discharge is characterized by strong oscillatory behaviour with various waveforms correlated with jumps in the static I–V characteristics. Space-resolved measurements through the two aligned orifices of the two grids show a peak increase of the electron temperature and particle density in the regions of the two space-charge structures. The effects of the biases and Ar pressure on the overall spatial distribution of all plasma parameters are investigated. Two important working points of the concentric double hollow grid cathode discharges are revealed which could make this configuration suitable as an electron source.
C.T. Teodorescu-Soare, S.A. Irimiciuc, C. Ionita, D.G. Dimitriu, B. Hodoroaba, T. O’Hara, O. Vasilovici, L. Amarandi, R.W. Schrittwieser, Concentric double hollow grid cathode discharges, International Journal of Mass Spectrometry, Volume 436, 2019, Pages 83-90, ISSN 1387-3806, DOI: 10.1016/j.ijms.2018.11.019.