Physical origin of current filaments in DC gas discharges

Current filamentation observed in DC gas discharges is explained considering a self-organization process, the result of which is a nearly spherical double layer known as anode spot. Accelerating electrons at energies sufficient to produce ionizations, the double layer acts as an internal source of charged particles. The striated column, working as current filament, appears after the double layer "multiplication." The balance between the repulsive electric forces and the attractive magnetic forces acting between striated columns explains the ordered distribution of the current filaments at the anode surface.