2016
Ref: POSTER-2017-0015

The discovery of an electron current at Earth's McIlwain L=6

Poster presented at European Space Weather Week 13, Oostende, Belgium on 2016-11-15

Abstract: The Large Yield RAdiometer (LYRA) is an ultraviolet radiometer on-board ESA's PROBA2 micro-satellite. Since its 2009 launch it observes the Sun in four different passbands, chosen for their relevance to solar physics, aeronomy and space weather. Flying on an altitude of 725 km, LYRA proved to be an excellent flare monitor and is involved in the analysis of the atmospheric composition of the Earth. One of the most peculiar and intriguing results of LYRA is the detection of short, strong, bursts that do not directly correlate with solar coronal events, neither with the pointing of the instrument to Earth's upper atmosphere, but correlate well with high Ap index on Earth's surface. The location of the PROBA2 spacecraft during those detections also correlates well with the Earth's magnetic field lines with a Mcilwain L-value of 5.8$\pm$0.8, providing an independent confirmation of the magnetic origin of these detections. Most intriguingly the $L=6$ Mcilwain surface extends to an area well inside the outer Van Allen belt. The same events are also observed by the Energetic Particle Telescope (EPT), an energetic particle detection instrument, on board ESA's PROBA-V mission. Similar detections made by the 2.4-8 $MeV$ electrons channel, providing us with the identification of the cause of the detections.

Keyword(s): PROBA2 ; LYRA ; Ionosphere ; In situ detections ; Ultra-relativistic electrons