Plasma Moses Effect: Production of Stationary Circular Holes in the Liquid Films by a DC Corona Discharge

A dc corona discharge from a needle electrode was studied over thin liquid films such as water, hydrogen peroxide, glycerin, and albumin. The self-maintained plasma Moses effect (ME) was demonstrated; the effect presents itself the formation of stationary circular holes in the films of these liquids. It was found that the holes in the films remain for several days until they are completely dried out. The ME on the coffee colloidal solution was studied. A famous effect of coffee rings near a hole in the dried coffee liquid film was recorded for the first time. It was revealed that cracks of a wavy type appear in the dried coffee ring.