  Coagulation growth kinetics of nanoparticles in plasma is affected by
inter-particle electrostatic forces due to charging phenomenon. In stationary
plasmas, unipolar charging of particles results in retardation of particles
growth and may result in limitation on a particle size. We demonstrate opposite
effect of enhanced particles growth in atmospheric pressure non-stationary arc
discharge. Modeling of the nanoparticles growth kinetics revealed the formation
of bipolar charge distribution. As a result, reversed (attractive) Coulomb
forces promote formation of micrometer size particles in a millisecond time
scale as observed in experiment.
