2024/04/29 by Yutaka Ohira, Ohira, Yutaka
Earth and Planetary Sciences · Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Dark Matter and Cosmic Phenomena #Earthquake Detection and Analysis #FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE) #Plasma Physics (physics.plasm-ph)
paper · pdf · doi:10.48550/arxiv.2404.18513
openalex publication_date 2024/04/29 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We recently found that streaming cosmic rays (CRs) induce a resistive electric field that can accelerate secondary electrons produced by CR ionization. In this work, we study the evolution of the energy spectrum of secondary electrons by numerically solving the one-dimensional Boltzmann equation and Ohm's law. We show that the accelerated secondary electrons further ionize a gas, that is, the electron avalanche occurs, resulting in increased ionization and excitation of the gas. Although the resistive electric field becomes weaker than one before the CR discharge, the weak resistive electric field weakly accelerates the secondary electrons. The quasi-steady state is almost independent of the initial resistive electric field, but depends on the electron fraction in the gas. The resistive electric field in the quasi-steady state is larger for the higher electron fraction, which makes the number of secondary electrons that can ionize the gas larger, resulting in a higher ionization rate. The CR discharge could explain the high ionization rate that are observed in some molecular clouds.