The solar-cycle and 27-day patterns of solar-wind plasma types at earth and the magnetospheric reactions

There are 27-day patterns and solar-cycle patterns to the passage of different solar-wind plasma types at Earth given off by the different regions of the rotating, changing Sun. The four types of solar-wind plasma are coronal-hole-origin plasma, streamer-belt-origin plasma, sector-reversal-region plasma, and ejecta. The different plasma types have systematically different properties (e.g., solar-wind speed, magnetic-field strength, Mach number, and Alfvénicity) The different plasmas produce different environments for the Earth and each plasma type drives the Earth differently, producing 27-day and solar-cycle temporal patterns of geomagnetic activity. Geomagnetic storms occur mainly during coronal-hole-origin plasma (modulated by the Russell-McPherron effect) and during ejecta and geomagnetic calms occur during sector-reversal-region plasma and streamer-belt-origin plasma. For coronal-hole-origin plasma at Earth, an interplay between the hemispheric-number asymmetry of sunspots and the 22-year Hale magnetic cycle has been seen that will affect the occurrence of high-speed-stream-driven storms at Earth and the intensity of the electron radiation belt by biasing the Russell-McPherron effect. For the different solar-wind plasmas, the difference in driving and the different ambient environments both effect the particle populations of the Earth’s magnetosphere such as the cold plasmasphere, the magnetotail plasma sheet, and the electron radiation belt. The interactions of solar-wind plasmas, geomagnetic activity, and magnetospheric particle populations are explored in the present study, with particular attention paid to 27-day and solar-cycle variations.