Relationship between solar energetic particle intensities and coronal mass ejection kinematics using STEREO/SECCHI field of view

TL;DR

This study investigates the relationship between CME kinematics and SEP intensities using STEREO/SECCHI data during solar cycle 24, revealing correlations between CME speeds, Mach numbers, and SEP fluxes across different energy channels.

Contribution

It provides detailed analysis of CME and SEP data from STEREO/SECCHI, highlighting correlations between CME kinematic parameters and SEP intensities, with insights into particle reacceleration mechanisms.

Findings

High correlation between CME speed and SEP fluxes for western events.

Strong correlation between Mach number at SEP peak and SEP fluxes.

Estimates of delays between CME, SEP, and shock parameters.

Abstract

Solar energetic particles (SEPs) accelerated from shocks driven by coronal mass ejections (CMEs) are one of the major causes of geomagnetic storms on Earth. Therefore, it is necessary to predict the occurrence and intensity of such disturbances. For this purpose we analyzed in detail 38 non-interacting halo and partial halo CMEs, as seen by the Solar and Heliospheric Observatory /Large Angle and Spectrometric Coronagraph (SOHO/LASCO), generating SEPs (in >10 MeV, >50 MeV, and >100 MeV energy channels) during the quadrature configuration of the Solar TErrestrial RElations Observatory (STEREO) twin spacecrafts with respect to the Earth, which marks the ascending phase of solar cycle 24 (i.e., 2009-2013). The main criteria for this selection period is to obtain height-time measurements of the CMEs without significant projection effects and in a very large field of view. Using the data from STEREO/Sun Earth Connection Coronal and Heliospheric Investigation (STEREO / SECCHI) images we determined several kinematic parameters and instantaneous speeds of the CMEs. First, we compare instantaneous CME speed and Mach number versus SEP fluxes for events originating at the western and eastern limb we observe high correlation for the western events and anticorrelation for the eastern events. Next we investigated instantaneous CME kinematic parameters such as maximum speed, maximum Mach number, and the CME speed and Mach number at SEP peak flux versus SEP peak fluxes. Highly positive correlation is observed for Mach number at SEP peak flux for all events. The obtained instantaneous Furthermore, we conducted estimates of delay in time and distance between CME, SEP, and shock parameters. Comparative studies of the considered energy channels of the SEPs also throw light on the reacceleration of suprathermal seed ions by CME-driven shocks that are pre-accelerated in the magnetic reconnection.