Observations of a broad and dynamic region of radiation in geospace

► Found a broad and dynamic region of radiation in geospace. ► It centers at the magnetospheric cusp and has a size of up to 10.5 Earth radii. ► It is filled with energetic particles and strong electromagnetic fluctuations. ► It is observed on both open and closed geomagnetic field lines. ► It provides a direct particle source for the outer radiation belt/ring current.