  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.
