The nonmonotonicity of transition from Faraday dark space to positive column and the emergence of standing strata behind the cathode region of glow discharge

The region of transition from the Faraday dark space to an extended homogeneous positive column in a glow discharge is treated. The results of analysis of the set of equations for the discharge (in a hydrodynamic approximation) and numerical solution of the set of equations for helium are used to demonstrate that the transition is nonmonotonic. In the general case, the nonmonotonicity exhibits the behavior of damped vibrations. However, in the absence of nonlinear ionization processes such as stepped ionization of accumulating metastable atoms, the vibrational mode is damped so rapidly as to transform to aperiodic. A clearly defined field maximum and a plasma density minimum appear in the transition region. In the case of strong currents, when stepped ionization is significant, nonlinear ionization supports the vibrational mode. The theoretically derived static strata, decaying from the cathode part of the discharge to the anode, were observed experimentally almost half a century ago.