Impacts on Proton Fluxes Observed During Different Interplanetary Conditions

Abstract

Interplanetary coronal mass ejections (ICMEs) and corotating interaction regions (CIRs) are the major characteristic events of the solar wind (SW). We used proton flux data with different energy levels provided by the Low Energy Magnetic Spectrometers (LEMS) 120 system of the Electron, Proton and Alpha Monitor (EPAM) for studying different ICME-driven and CIR-driven storms. Our main aim was to find, from the observational results, the nature of the proton flux during solar storms driven by different mechanisms that, in our cases, are related to ICMEs and CIRs, in the interplanetary regions. We analyzed the different parameters provided by the LEMS 120 system and compared them during the different storm types and during a selected quietest day as well. We studied four events: a geomagnetically quiet day, two ICME-driven storms and one CIR-driven storm. We also analyzed the interplanetary magnetic field (IMF) magnitude (Bmag$B_{\\mathrm{mag}}$) and the different SW parameters during all these events. We observed that both the prolonged particle precipitations during CIRs and the intense particle precipitations during ICMEs result in the different nature of the fluxes with different energy levels compared with other parameters such as Bmag$B_{\\mathrm{mag}}$, and the SW velocity (Vsw$V_{\\mathrm{sw}}$). Our quiet-period results show that there is a strong correlation between the higher energy proton fluxes and Bmag$B_{\\mathrm{mag}}$ and Vsw$V_{\\mathrm{sw}}$ and a weak correlation in the case of lower energy protons. Our storm-time results demonstrate that when the storm is either driven by ICMEs or CIRs, the lower energy protons also starts to show positive correlations with Bmag$B_{\\mathrm{mag}}$ and Vsw$V_{\\mathrm{sw}}$ with a 0 min time lag (TA) during ICMEs and with a ≈−100min${\\approx}\\,{-}100~\\mbox{min}$ TA during CIRs. During the quiet day, the proton flux observed was due to the perturbations created by ionization and the higher energy of the protons sufficiently weakened. Whereas, the CME speed, the preceding CMEs, and the presence of pre-existing solar energetic particles (SEPs) in the ambient medium, the makeup of CIR-related winds, and the nature of precipitation during both ICMEs and CIRs caused the proton fluxes with different energy levels during storm times.