Ion or electron beams can be emitted from liquid metal wetted needles,
or from capillaries or slits into which the liquid metal is allowed t
o flow. Large-area liquid metal field emission sources have been propo
sed recently, using either two-dimensional, regular arrays of cones or
capillaries, or even a substrate with an intrinsically microstructure
d surface covered by a liquid metal film. Now this latter concept has
been realized in a pilot experiment by in situ wicking and wetting of
a porous sintered metal disk. A similar concept had been applied forme
rly on a mercury film cathode supporting a low pressure are discharge.
Microstructured liquid metal ion or electron sources (MILMIS/MILMES)
are capable of operating in a pulsed mode at a current level which is
orders of magnitude above that for steady-state operation.