Transient analysis of light brightness emitted from high power microwave nitrogen breakdown under external dc magnetic field

Abstract

A three-dimensional (3D) multi-physics model is developed to describe the characteristics of light emitted from high power microwave nitrogen breakdown. This model consists of electromagnetic (EM) fields and plasma physics in which plasma physics and EM fields are controlled by plasma fluid equations and Maxwell's equations. A continuity equation of excited molecule (ion) is introduced into the fluid model to describe the light brightness produced in the breakdown system. The resulting multi-physics system is analyzed and described with the spectral-element time-domain method. The external dc magnetic field applied in breakdown volume is used to prolong the breakdown time. The light brightness is weakened by the dc magnetic field before the occurrence of breakdown, and the variation in light brightness with different wavelengths produced by breakdown is discussed. The position of the maximum light brightness spot can be changed by the influence of the dc magnetic field on the electron concentration. Our research provides theoretical guidance for further understanding the physical process and physical phenomena in microwave nitrogen breakdown.