Constructing the global distribution of chorus wave intensity using measurements of electrons by the POES satellites and waves by the Van Allen Probes

Abstract

We adopt a physics-based technique to infer chorus wave amplitudes from the low-altitude electron population (30-100 keV) measured by multiple Polar Orbiting Environmental Satellites (POES), which provide extensive coverage over a broad region in L-shell and magnetic local time (MLT). This technique is validated by analyzing conjunction events between the Van Allen Probes measuring chorus wave amplitudes near the equator and POES satellites measuring the 30-100 keV electron population at the conjugate low altitudes. We apply this technique to construct the chorus wave distributions during the 8-9 October storm in 2012 and demonstrate that the inferred chorus wave amplitudes agree reasonably well with conjugate measurements of chorus wave amplitudes from the Van Allen Probes. The evolution of the chorus wave intensity inferred from low-altitude electron measurements can provide real-time global estimates of the chorus wave intensity, which cannot be obtained from in situ chorus wave measurements by equatorial satellites alone, but is crucial in quantifying radiation belt electron dynamics. Key Points Chorus-driven pitch angle scattering causes electron precipitation Two directional electron measurement is used to infer chorus wave intensity Physics-based technique provides real-time estimates on chorus wave intensity ©2013. American Geophysical Union. All Rights Reserved.