Frequency spectra and electrohydrodynamic phenomena in a liquid gallium field-ion-emission source

A detailed investigation of the emission frequency spectra of a gallium liquid metal ion source is presented. The spectra are correlated with current oscillograms. The current for which pulses appear superimposed on the d.c. level of current is well predicted by existing theory. The pulses are believed to be the result of droplet emission, and their terminal frequency appears to coincide with the frequency of vibration of the sides of the liquid cone at high currents. Better understanding of the instabilities that develop on the liquid anode can be useful for deposition purposes.