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Self-Consistent Numerical Framework for Multiscale Circuit-Plasma Coupling with Secondary Electron Emission

Hongbin Kim, Soung Yong Yun, Jaeguk Lee, Dong-Yeop Na

Abstract

Voltage breakdown in high-voltage pulsed vacuum systems arises from nonlinear multiscale interactions among circuit dynamics, kinetic plasma evolution, and ion-induced secondary electron emission (SEE) at electrode surfaces. Although circuit-plasma co-simulation frameworks couple lumped circuits with particle-in-cell (PIC) solvers, most neglect energy-resolved SEE and its feedback to both plasma and circuit, limiting predictive capability. We present a self-consistent framework for multiscale circuit-plasma coupling that incorporates ion-energy-dependent SEE into the electrode boundary of an electrostatic PIC solver. The emitted electron flux is included in the surface charge update, leading to a modified Poisson boundary condition that couples plasma and circuit within a unified formulation. Two integration strategies are developed: (i) a fully implicit strict coupling scheme solving the plasma-circuit system monolithically, and (ii) a weak coupling scheme based on operator splitting, compatible with SPICE solvers and enabling partitioned time integration with one-step lag. The framework is applied to a Tesla-transformer-driven vacuum capacitor with ion injection. Results show that SEE alters surface charge evolution, triggering rapid voltage collapse and sustaining a near-zero-voltage plateau, while SEE-free models fail. Agreement between strict and weak coupling confirms robustness. The method provides a unified framework for predictive simulation of multiscale circuit-plasma interactions.

Self-Consistent Numerical Framework for Multiscale Circuit-Plasma Coupling with Secondary Electron Emission

Abstract

Voltage breakdown in high-voltage pulsed vacuum systems arises from nonlinear multiscale interactions among circuit dynamics, kinetic plasma evolution, and ion-induced secondary electron emission (SEE) at electrode surfaces. Although circuit-plasma co-simulation frameworks couple lumped circuits with particle-in-cell (PIC) solvers, most neglect energy-resolved SEE and its feedback to both plasma and circuit, limiting predictive capability. We present a self-consistent framework for multiscale circuit-plasma coupling that incorporates ion-energy-dependent SEE into the electrode boundary of an electrostatic PIC solver. The emitted electron flux is included in the surface charge update, leading to a modified Poisson boundary condition that couples plasma and circuit within a unified formulation. Two integration strategies are developed: (i) a fully implicit strict coupling scheme solving the plasma-circuit system monolithically, and (ii) a weak coupling scheme based on operator splitting, compatible with SPICE solvers and enabling partitioned time integration with one-step lag. The framework is applied to a Tesla-transformer-driven vacuum capacitor with ion injection. Results show that SEE alters surface charge evolution, triggering rapid voltage collapse and sustaining a near-zero-voltage plateau, while SEE-free models fail. Agreement between strict and weak coupling confirms robustness. The method provides a unified framework for predictive simulation of multiscale circuit-plasma interactions.
Paper Structure (40 sections, 56 equations, 32 figures, 4 tables, 2 algorithms)

This paper contains 40 sections, 56 equations, 32 figures, 4 tables, 2 algorithms.

Figures (32)

  • Figure 1: Schematic diagram of the cathodic arc-based $\text{Ti}^+$ ion implantation and deposition system. (Created with the assistance of Nano Banana)
  • Figure 2: Simulation model comprising the simplified Tesla transformer circuit and the physical discharge domain.
  • Figure 3: Probability mass function of emitted secondary electrons for 40keV incident ions.
  • Figure 4: Energy dependence of the mean SEY. Experimental data are taken from Holmen1981Zalm1985.
  • Figure 5: Energy-weighted secondary electron energy spectra adapted from Ruano2008. Here, $N(E)$ denotes the number of emitted secondary electrons with kinetic energy $E$.
  • ...and 27 more figures