Liquid metal field emitters in problem of space vehicles charging limitation

It is shown that the liquid-metal sources allow one to obtain a stable direct current in a static field both in ion and electron regimes. It is possible to sustain each of the regimes in the same low-voltage range, under conditions of a relatively high residual gas pressure. Such emitters seem to be useful in the problem of space vehicle charging limitation. Being situated on the surfaces that have to be protected from the excess charge of an arbitrary polarity, the devices can automatically restrict the electric field below the level of 2.5÷4.0 kV/cm