Statistical Properties of Plasmaspheric Hiss From Van Allen Probes Observations

0490491 - ÚFA 2019 RIV US eng J - Článek v odborném periodiku
Hartley, D. P. - Kletzing, C. A. - Santolík, Ondřej - Chen, L. - Horne, R. B.
Statistical Properties of Plasmaspheric Hiss From Van Allen Probes Observations.
Journal of Geophysical Research-Space Physics. Roč. 123, č. 4 (2018), s. 2605-2619. ISSN 2169-9380. E-ISSN 2169-9402
Grant CEP: GA ČR GA17-07027S
Grant ostatní: AV ČR(CZ) AP1401
Program: Akademická prémie - Praemium Academiae
Institucionální podpora: RVO:68378289
Klíčová slova: plasmaspheric hiss * EMFISIS * Van Allen Probes * wave normal angle * bimodal * chorus waves
Obor OECD: Fluids and plasma physics (including surface physics)
Impakt faktor: 2.821, rok: 2018
https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2017JA024593

Van Allen Probes observations are used to statistically investigate plasmaspheric hiss wave properties. This analysis shows that the wave normal direction of plasmaspheric hiss is predominantly field aligned at larger L shells, with a bimodal distribution, consisting of a near-field aligned and a highly oblique component, becoming apparent at lower L shells. Investigation of this oblique population reveals that it is most prevalent at L < 3, frequencies with f/f(ce) > 0.01 (or f > 700 Hz), low geomagnetic activity levels, and between 1900 and 0900 magnetic local time. This structure is similar to that reported for oblique chorus waves in the equatorial region, perhaps suggesting a causal link between the two wave modes. Ray tracing results from HOTRAY confirm that it is feasible for these oblique chorus waves to be a source of the observed oblique plasmaspheric hiss population. The decrease in oblique plasmaspheric hiss occurrence rates during more elevated geomagnetic activity levels may be attributed to the increase in Landau resonant electrons causing oblique chorus waves to be more substantially damped outside of the plasmasphere. In turn, this restricts the amount of wave power that can access the plasmasphere and evolve into oblique plasmaspheric hiss. These results confirm that, despite the difference in location of this bimodal distribution compared to previous studies, a direct link between oblique equatorial chorus outside of the plasmasphere and oblique hiss at low L shells is plausible. As such, these results are in keeping with the existing theory of chorus as the source of plasmaspheric hiss.
Trvalý link: http://hdl.handle.net/11104/0284718