Interesting characteristics of rubidium vapour discharges

The basic properties of alkali vapor discharges are reviewed and exemplified for the case of rubidium vapor. The low arc drop exhibited by these discharges is their primary interesting feature. Arc drops as low as two volts with current densities up to one ampere per sqcm have been achieved. Behavior of pure alkali vapor discharges are highly temperature dependent. Experiments are described showing how the temperature dependence of the arc drop is substantially reduced by using an alkali vapor noble gas (Xenon) combination. The possibility of interruption of alkali vapor discharges by grid action is discussed in the light of the known theories pertaining to grid control of arc currents.