Glr. Mair, THE EFFECTS OF FLOW IMPEDANCE ON THE CURRENT-VOLTAGE CHARACTERISTICS OF LIQUID-METAL ION SOURCES, Journal of physics. D, Applied physics, 30(13), 1997, pp. 1945-1950
By incorporating the flow impedance into the space-charge model of Mai
r, the current-voltage curves of high impedance liquid-metal ion sourc
es can be fitted to this modified model for an assumed liquid film thi
ckness that decreases with voltage and/or for assumed values of the ch
ange in cone half-angle. The new model strongly suggests that what lim
its the current in high-impedance sources (and eventually in all sourc
es) is a decrease in film thickness with voltage. Coupled to this effe
ct is a self-shaping of the liquid emitter; the higher the flow impeda
nce of an ion source the more pronounced is this self-shaping.