A comparison of the impacts of CMEs and CIRs on the Martian dayside and nightside ionospheric species

TL;DR

This study compares how CMEs and CIRs affect Martian ionospheric species, revealing that CIRs have a more significant impact on the nightside ionosphere, especially during the declining phase of solar cycle 24.

Contribution

It provides a comparative analysis of the effects of CMEs and CIRs on Martian ionospheric species using MAVEN data, highlighting differences in impact magnitude and altitude profiles.

Findings

CIRs cause more pronounced ionospheric disturbances than CMEs on Mars.

Nightside ionosphere shows greater variation than dayside during these events.

Impact of CIRs is more prominent during the declining phase of solar cycle 24.

Abstract

Measurements from the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft, orbiting Mars are used for investigating the impact of coronal mass ejections (CMEs) and corotating interaction regions (CIRs) on Martian ionospheric species. We have chosen 15 CME and 15 CIR events (2015-2020) at Mars from the existing catalogs. We have extensively analyzed the Martian dayside and nightside profiles of ionospheric species during each of the CME and CIR events. We have selected those orbit plasma density profiles which showed significant differences from the mean quiet-time profile during each event. The primary focus of this paper is to provide a comparative average scenario of the variation of Martian ionospheric species during CMEs and CIRs events. A significant difference can be observed in the profiles of the Martian dayside and nightside ionospheric species (O+, O2+, CO2+, NO+, C+, N+, & OH+) during CMEs and CIRs in comparison to mean quiet-time profile. The difference is more prominent on the nightside compared to the dayside ionosphere. During CIRs, the nightside ion density is nearly one order of magnitude less (above 250 km) in comparison to CMEs. The mean peak altitude and density of the lighter ions (O+, C+, N+, & OH+) were at lower altitudes during the CIRs compared to CMEs. Therefore, this study suggests that during the declining phase of solar cycle (SC 24), the impact of CIRs on the Martian ionospheric species is more prominent compared to CMEs.