Numerical simulations of solar energetic particle event timescales associated with ICMES

TL;DR

This paper uses numerical simulations to analyze solar energetic particle event timescales related to ICMEs, revealing dependencies on CME speed and width that align with observations but also providing new insights.

Contribution

The study introduces a transport model for SEPs considering ICME shocks, showing that TD depends on CME speed but not on CME width, contrary to previous observational analysis.

Findings

TD increases with CME speed and width in simulations.

TD is directly dependent on CME speed, not on CME width.

Simulation results align with spacecraft data analysis.

Abstract

Recently, S.W. Kahler studied the solar energetic particle (SEP) event timescales associated with coronal mass ejections (CMEs) from spacecraft data analysis. They obtained different timescales of SEP events, such as TO, the onset time from CME launch to SEP onset, TR, the rise time from onset to half the peak intensity (0.5Ip), and TD, the duration of the SEP intensity above 0.5Ip. In this work, we solve SEPs transport equation considering ICME shocks as energetic particle sources. With our modeling assumptions, our simulations show similar results to Kahler's spacecraft data analysis that the weighted average of TD increases with both CME speed and width. Besides, from our simulation results, we suggest TD is directly dependent on CME speed, but not dependent on CME width, which were not achieved from the observation data analysis.