Doubly forced anharmonic oscillator model for floating potential fluctuations in DC glow discharge plasma

The Floating Potential Fluctuations (FPF) observed in a dc glow discharge plasma powered with two sources is modeled using an anharmonic oscillator with two forcing terms. In the discharge system, one of the electrode is biased to a negative voltage source (i.e. cathode), and the second electrode is biased to a positive voltage source (i.e. anode), while the stainless-steel vacuum chamber is grounded. The dc glow discharge plasma is generated by application of negative voltage on the cathode with respect to the grounded chamber using one of the power supplies. On application of positive voltage to the anode using second power supply results in formation of potential structure on achieving the triggering criteria. This potential structure is referred as anodic double layer (ADL). The evolution of ADL is associated with FPF. Therefore, FPF is analyzed to characterize the ADL's dynamical features. In this work, the experimentally observed FPF compared with numerically obtained oscillations using an anharmonic oscillator model with two forcing terms. Each of these forcing terms are associated with the two power supplies used in the experiment. The experimentally and numerically obtained oscillations from the model are studied using phase-space plot, FFT, Largest Lyapunov exponent (LLE). The dynamical features of oscillations obtained by the model show strong agreement with the experiment and can be extended for a description of complex systems driven by multiple forces. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

In this study, the Floating Potential Fluctuations (FPF) observed in a dc glow discharge plasma powered with two sources were successfully modeled using an anharmonic oscillator with two forcing terms. The dynamical features of the FPF were found to be associated with the formation and evolution of the anodic double layer (ADL). The experimentally and numerically obtained oscillations from the model showed strong agreement and can be extended for the description of complex systems driven by multiple forces.