A New Method for Inferring the Electron Plasma Density in the Inner Belt Region

0518221 - ÚFA 2020 US eng A - Abstract
Hartley, D. - Kletzing, C. - de Pascuale, S. - Kurth, W. - Santolík, Ondřej
A New Method for Inferring the Electron Plasma Density in the Inner Belt Region.
AGU Fall Meeting. Washington: American Geophysical Union, 2019. SM54A-04.
[AGU Fall Meeting 2019. 09.12.2019-13.12.2019, San Francisco]
Institutional support: RVO:68378289
Keywords : plasmasphere * plasmaspheric hiss * EMFISIS * Van Allen Probes
OECD category: Fluids and plasma physics (including surface physics)
https://agu.confex.com/agu/fm19/meetingapp.cgi/Paper/492312

Coupling cold plasma theory with electromagnetic observations of plasmaspheric hiss from the Van Allen Probes EMFISIS Waves instrument, we present a new method of inferring the electron plasma density in the inner radiation belt region. Using the cold plasma dispersion relation we relate the ratio of E/cB to the index of refraction, which, in turn, is a function of plasma density. This methodology provides a density estimate time interval where plasmaspheric hiss is observed. We show that these density estimates are generally in agreement with other methodologies, but in order to further improve accuracy we perform a statistical calibration against the density inferred from the upper hybrid line. This allows us to mitigate against antenna-plasma coupling effects, as well as actively selecting frequency channels where the calculation is shown to be more reliable. The resulting hiss-inferred densities are demonstrated to be accurate both statistically and for individual events. Given that this new methodology is not subject to the same instrumental upper limit as densities inferred via other techniques on the Van Allen Probes, it permits density values to be extended to lower L shells and in to the inner zone. Inside L = 2.5, hiss‐inferred densities offer over 70% data coverage, whereas other methods provide data approximately 10-20% of the time. This methodology facilitates the calculation of event‐specific electron densities in the inner belt region, and therefore diffusion coefficients, as opposed to relying on empirical models for periods when densities from other sources are not available.
Permanent Link: http://hdl.handle.net/11104/0303381