Response of Thermospheric Nitric Oxide (NO) Cooling During Events of Strong Solar Wind Pressure

Abstract

Nitric oxide (NO) infrared emissions are a notable indicator for varying thermospheric energy budget during geomagnetic storms while the Interplanetary Magnetic Field (IMF) is southward. In this study, we present the first investigation on the response of NO cooling emissions during northward IMF conditions. Twenty three isolated events spanning over 23 years between 2002 and 2024 have been considered in this study. For 5 December 2004 event the peak solar wind pressure was 25 nPa and dSYMH/dt was 21 nT min ⁻¹ , where a clear enhancement in NO infrared emissions was observed. This event has been studied in detail. The correlation between energetic particle precipitation fluxes and solar wind pressure variations in the high latitude regions for ions and electrons has been investigated during these events. This study suggests that events showing enhanced NO infrared radiative cooling during positive IMF‐ and elevated solar wind pressure are also accompanied by dominant soft electrons (<1 keV), electrons (1–10 keV), and ions (>10 keV) precipitation.