Higher Harmonics in Multipactor Induced Plasma Ionization Breakdown near a Dielectric Surface

Area of Science:

• Plasma Physics
• Electromagnetics
• Nonlinear Optics

Background:

• Multipactor discharge is a resonant electron discharge phenomenon occurring in vacuum electronic devices.
• Plasma generation via ionization breakdown near dielectric surfaces is crucial for understanding high-power microwave interactions.
• Higher harmonic (HH) generation is a nonlinear process observed in various physical systems.

Purpose of the Study:

• To investigate the novel physics of higher harmonic generation in the normal electric field near a dielectric surface.
• To elucidate the underlying mechanism of HH generation during multipactor induced plasma ionization breakdown.
• To compare theoretical predictions with simulation results for HH frequency and growth rates.

Main Methods:

• Kinetic particle-in-cell (PIC) simulations were employed to model the plasma dynamics.
• A theoretical framework was developed to explain the observed HH generation.
• Analysis focused on the interaction between the plasma and the dielectric surface under radio frequency (RF) driving fields.

Main Results:

• Novel physics of HH generation was identified in the normal electric field near a dielectric surface.
• Observed HH frequencies were approximately ten times the fundamental RF driving frequency.
• The electron plasma frequency was found to be higher than the generated HH frequency.
• Stream plasma interaction-induced instability was identified as the HH generation mechanism in the collisional regime.

Conclusions:

• Kinetic PIC simulations and developed theory show good agreement regarding HH frequency and growth rates.
• The study provides a fundamental understanding of HH generation in RF-driven plasmas near surfaces.
• This work contributes to the physics of nonlinear plasma phenomena and high-power microwave applications.