A comparative study on geoeffective and non-geoeffective corotating interaction regions

A long database of corotating interaction regions (CIRs) is used to investigate their geoeffectiveness. Among 290 CIR events identified during Solar Cycle 24 (2008-2019), 88 (30%) are found to be geoeffective in causing geomagnetic storms with the symmetric ring current index [SYM-H] peak 6-50 nT, and 202 (70%) are non-geoeffective with the minimum SYM-H >-50 nT. Based on a comparative study of the geoeffective and non-geoeffective CIRs, following results are obtained. Geoeffective and non-geoeffective CIRs have comparable duration (28 +/- 15 hours, 26 +/- 14 hours, respectively) and radial extent (0.33 +/- 0.17 AU, 0.30 +/- 0.17 AU, respectively), on average. While the mean solar-wind plasma speed during the geoeffective (503 +/- 70 km s-1) and non-geoeffective (491 +/- 63 km s-1) CIRs exhibits no statistical difference, the geoeffective CIRs have 25% higher peak plasma density, 45% higher ram pressure, 42% higher temper-ature, 39% higher interplanetary magnetic field (IMF) magnitude, 57% stronger IMF southward component, and 61% stronger reconnection electric field than the non-geoeffective events, on average. The auroral electrojet index [AE] and SYM-H are found to be, respectively, 58% and 192% stronger during the geoeffective CIRs than the non-geoeffective events. The typical characteristic solar -wind and geomagnetic activity parameters given in this article can be useful for space weather modeling and prediction purposes.(c) 2022 COSPAR. Published by Elsevier B.V. All rights reserved.