The Characteristics of Solar Wind Parameters During Minimum Periods of Solar Cycle 24 and Impact on Geoeffectiveness

摘要

We study the solar wind parameters during the extended minimum phase of solar cycle 24 within period of 2007 to 2009. We used GOES and ACE satellites hourly data to obtain the distribution of solar wind density and speed, solar energetic particles (electron, proton and ion), solar radio flux, interplanetary magnetic field and global geomagnetic variation of DsT index. All parameters did not occur simultaneously that refers to complexity of their sources and interactions along interplanetary medium. The minimum phase of solar cycle depends on the used tracer. Plasma particles and magnetic activities have come later of about 15 months than sunspot minimum. Electron density and proton speed are good solar wind parameters for detecting solar minimum phase. We define the minimum of magnetic environment (MME) as a fluctuation of DsT in ±10 nT, Bz in ±5 nT and Bmag in 5 nT within consecutive 3 months period.