Stability of the cathode layer of normal glow discharge in argon

The conditions of stability of the cathode layer for the normal regime of glow discharge are considered within the framework of the classical theory of the cathode layer where the requirement of a certain current radius is reduced to a force which acts on the ions of the cathode plasma. The specific force on ions is evaluated from the condition of the cathode voltage minimum. It is shown that stepwise ionization is absent in the cathode region of normal glow discharge.