Abstract
General scenarios of transitions between different spot patterns on electrodes of DC gas discharges and their relation to bifurcations of steady-state solutions are analyzed. In the case of cathodes of arc discharges, it is shown that any transition between different modes of current transfer is related to a bifurcation of steady-state solutions. In particular, transitions between diffuse and spot modes on axially symmetric cathodes, frequently observed in the experiment, represent an indication of the presence of pitchfork or fold bifurcations of steady-state solutions. Experimental observations of transitions on cathodes of DC glow microdischarges are analyzed and those potentially related to bifurcations of steady-state solutions are identified. The relevant bifurcations are investigated numerically and the computed patterns are found to conform to those observed in the course of the corresponding transitions in the experiment.
Highlights
Luminous spots on electrodes of direct current glow and arc discharges and self-organized patterns of spots represent a very interesting phenomenon, which is important for applications
The theoretical description of spots and spot patterns on electrodes of dc glow and arc discharges is based on the multiplicity of solutions: an adequate theoretical model must in some cases allow multiple steady-state solutions to exist for the same conditions, with different solutions describing the spotless mode of current transfer and modes with different spot configurations
Bifurcations of steady-state solutions manifest in experiments as transitions between modes with different spot patterns, which occur as the discharge current I is varied
Summary
Luminous spots on electrodes of direct current glow and arc discharges and self-organized patterns of spots represent a very interesting phenomenon, which is important for applications. If an abrupt transition occurs in a monotonic way, i.e., without temporal oscillations of the electrode luminosity and discharge parameters, in particular, discharge voltage, the increment of the perturbations, against which the stability is lost and which normally have a symmetry lower than that of the initially existing mode, is real and vanishes at I = I0. It is doubling of period with respect to the azimuthal angle, i.e., branching from a 3D mode with one of the periods π, π/2, π/3, π/4 etc of a 3D mode with double this period It follows, in particular, that transitions with changes of symmetry of other types cannot occur through pitchfork bifurcations of steady-state solutions, and are always abrupt. This reasoning will be applied to particular cases of cathodes of arc and dc glow discharges
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
