Study of stability of dc glow discharges with the use of Comsol Multiphysics software

Abstract

Stability of different axially symmetric modes of current transfer in dc glow discharges is investigated in the framework of the linear stability theory with the use of Comsol Multiphysics software. Conditions of current-controlled microdischarges in xenon are treated as an example. Both real and complex eigenvalues have been detected, meaning that perturbations can vary with time both monotonically and with oscillations. In general, results given by the linear stability theory confirm intuitive concepts developed in the literature and conform to the experiment. On the other hand, suggestions are provided for further experimental and theoretical work.

Computing Different Modes on Cathodes of DC Glow and High‐Pressure Arc Discharges: Time‐Dependent Versus Stationary Solvers

“…In contrast to what happens in the more detailed model to which Figure refers, in this case, the 1D mode reveals no retrograde behavior (hysteresis) and there is no problem in computing it in the 1D domain by means of the time‐dependent solver in the whole range of its existence, from A to B (high to low currents) and B to A (low to high currents). The same is true also for computation performed in the 2D domain, in spite of this mode being unstable against 2D perturbations between the bifurcation points and . On the other hand, the time‐dependent solver does not allow computation of any state belonging to the 2D mode.…”

“…The simplest discharge mode in this case is the 2D mode comprising the (2D) Townsend discharge at low currents, the subnormal discharge and discharge with the normal spot at intermediate currents, and the abnormal discharge at high currents. The CVC of this mode is shown in Figure of ref . and is similar to those computed in previous works by means of time‐dependent solvers (e.g., Figure and Figure ), except for the small retrograde section connecting the Townsend and subnormal discharges and denoted in above‐mentioned figure.…”

“…The time‐dependent solver cannot compute the retrograde section. However, it is able to compute all the rest of the mode, and this is again in contradiction with the linear stability theory: there is a wide current range ( in the above‐mentioned figure) where all steady states are unstable against 2D perturbations …”

“…To this end, results given by time-dependent solvers of COMSOL Multiphysics will be analyzed in light of information on stability of different steady states, which has been obtained in previous works in the framework of the linear stability theory, analytically and by means of the eigenvalue solver of COMSOL for arc cathodes [23,24] and by means of the COMSOL eigenvalue solver for axially symmetric states of DC glows. [25]…”

“…The same is true also for computation performed in the 2D domain, in spite of this mode being unstable against 2D perturbations between the bifurcation points a 1 and b 1 . [25] On the other hand, the time-dependent solver does not allow computation of any state belonging to the 2D mode.…”