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The 3rd ERG Mission Science Workshop
September 5-8, 2017
ASIAA, Taipei / NCKU, Tainan

Oral Presentation

A sudden change in long-term displacement of the Earth's radiation belt

Alexei Dmitriev (Institute of Space Science, National Central University, Taiwan)

The configuration and location of the Earth’s radiation belts are changing with the geomagnetic field. The secular variation in the geomagnetic field was accelerating during resent decades. Sudden changes in the acceleration occurred in the years 2006, 2009, and 2012 –2013. The latter one was most prominent. We determined latitudinal location of the outer radiation belt (ORB) within last 15 years with using NOAA/POES observations of energetic electrons at ~800 km circular orbit. We found that the ORB was shifted by 1 deg poleward in the Northern American region and by 2 deg equatorward in the Siberian region. The displacement corresponded qualitatively to the change of geomagnetic field predicted by the IGRF-12 model with taking into account the accelerating secular variation. However, the shift in the Siberian region was found to be ~1 deg larger. The difference became prominent after 2012 that might be related to the geomagnetic jerk occurred in 2012 – 2013. The displacement of ORB to lower latitudes in the Siberian region can contribute to the increase in occurrence rate of mid-latitude auroras observed in the Asian regions.