Electron kinetic effects in atmosphere breakdown by an intense electromagnetic pulse

Area of Science:

• Atmospheric Physics
• Plasma Physics
• Computational Physics

Background:

• Powerful electromagnetic pulses (EMPs) can significantly alter atmospheric electron kinetics.
• Understanding electron behavior is crucial for atmospheric discharge phenomena.
• Previous models may not fully capture the effects of high-energy electrons.

Purpose of the Study:

• To develop and apply a physical model for electron kinetics driven by EMPs in Earth's atmosphere.
• To investigate the role of different electron groups (slow and fast) in atmospheric discharges.
• To explain phenomena like multiple lightning discharges observed during thermonuclear tests.

Main Methods:

• Numerical solution of the Boltzmann kinetic equation for two electron groups.
• Two-term approximation for slow electrons (below a few keV) with weak anisotropy.
• Modified macroparticle method for fast electrons (above a few keV), including acceleration, energy loss, and scattering.
• Application to electric discharge in gamma-ray pre-ionized nitrogen.

Main Results:

• Runaway electrons significantly influence the energy distribution of free electrons.
• The presence of runaway electrons affects the avalanche ionization rate.
• The model provides a potential explanation for multiple lightning discharges observed in historical tests.

Conclusions:

• The proposed physical model accurately describes electron kinetics under strong EMPs.
• Runaway electrons are a critical factor in atmospheric ionization processes.
• This research offers insights into the mechanisms behind intense atmospheric electrical discharges.