  Brown Dwarf and extrasolar planet atmospheres form clouds which strongly
influence the local chemistry and physics. These clouds are globally neutral
obeying dust-gas charge equilibrium which is, on short time scales,
inconsistent with the observation of stochastic ionisation events of the solar
system planets. We argue that a significant volume of the clouds in Brown
Dwarfs and extrasolar planets is susceptible to local discharge events. These
are electron avalanches triggered by charged dust grains. Such intra-cloud
discharges occur on time scales shorter than the time needed to neutralise the
dust grains by collisional processes. An ensemble of discharges is likely to
produce enough free charges to suggest a partial and stochastic coupling of the
atmosphere to a large-scale magnetic field.

Earth and Planetary Astrophysics