Field-Aligned Electron Events Observed in the Radiation Belts by the HOPE Instruments aboard the Van Allen Probes

Tuesday, 15 December 2015
Poster Hall (Moscone South)
Solène Lejosne1, Oleksiy V Agapitov2 and Forrest Mozer1, (1)University of California Berkeley, Berkeley, CA, United States, (2)Laboratoire de Physique et Chimie de l'Environnement et de l'Espace, Orléans Cedex 2, France
Field-aligned electron events (FAEs) are defined as events having the ratio of field-aligned to perpendicular flux greater than three. Time Domain Structures (TDS) are known to produce FAEs. Whistler and ECH waves are other possible candidates. Our objective is to derive the general features of the FAEs, to identify their driving mechanisms and to evaluate the importance of the different mechanisms. More than two years of measurements by the Helium Oxygen Proton Electron mass spectrometer and the Electric Field and Waves experiment are analyzed to identify low-energy (100eV-50keV) FAEs and to quantify the concurrent electric and magnetic wave components. We also peek at the observable waveforms with bursts of high-time resolution measurements. From statistical analysis and case studies, we suggest in particular that TDS cause field-alignment of ~300eV electrons in the pre-midnight sector while chorus waves cause field-alignment of electrons of ~10keV in the morning sector of the outer belt.