An analogy to the Reynolds number for the neutral gas component of a weak plasma

The Reynolds number Re is used as a metric to assess whether or not a flow may contain turbulence. In a weakly ionised gas with an external electric f ield imposed, ions exert a drag on the neutral particles. Thus, a component of the neutral motion is attributable to the ion-drag. An analogy to Re ha s been proposed in which the ion-drag-induced velocity contribution to the neutral motion is used. This analogy thus represents the destabilising effe ct of the electric field on the neutral dynamics. Here quantisation of this proposed metric is investigated.