>2 MeV electron flux variation in 1998-2015 (GOES10/GOES11/GOES15) 135°W
Electron Flux Variation
This plot shows a long-term (1998 - 2015) variation of >2MeV electron flux observed by GOES series at a geostationary orbit. Hourly averaged, yearly averaged, and yearly maximum fluxes are shown as thin-, heavy-, and dotted-lines, respectively.
1
In 2003 – 2008, the flux level increased because of the declining phase of the solar activity that repeated every 11 years.
2
In the past 15 years, the maximum electron flux was recorded at 28 July 2004, which exceeded 3x105[electrons/cm2 sr s].
3
In 2009, the flux level of radiation belt electrons was relatively low compared with the past several years because of the minimum phase of the solar activity. During the period, both the solar wind speed and the sunspot number were low.
Solar wind speed and relative sunspot number (SSN) variations
This graph shows variations of solar wind speed and relative sunspot number during 1998-2015. Solar activities (associated with solar wind speed) influence electron flux variations in the radiation belts.