# Sensitivity Analysis of Excited-State Population in Plasma Based on Relative Entropy

## TL;DR

This paper introduces a new method to evaluate transient plasmas using relative entropy and statistical physics, aiming to improve industrial applications and energy understanding.

## Contribution

The novelty lies in using relative entropy and fractional Brownian motion in a revised collisional–radiative model to assess plasma dynamics.

## Key findings

- Excited states with high statistical weight can hinder plasma energy relaxation.
- The proposed method evaluates how far a plasma system is from steady state.
- Energy flow understanding could lead to innovations in plasma-related industries.

## Abstract

A highly versatile evaluation method is proposed for transient plasmas based on statistical physics. It would be beneficial in various industrial sectors, including semiconductors and automobiles. Our research focused on low-energy plasmas in laboratory settings, and they were assessed via our proposed method, which incorporates relative entropy and fractional Brownian motion, based on a revised collisional–radiative model. By introducing an indicator to evaluate how far a system is from its steady state, both the trend of entropy and the radiative process’ contribution to the lifetime of excited states were considered. The high statistical weight of some excited states may act as a bottleneck in the plasma’s energy relaxation throughout the system to a steady state. By deepening our understanding of how energy flows through plasmas, we anticipate potential contributions to resolving global environmental issues and fostering technological innovation in plasma-related industrial fields.