Effects of whistler mode hiss waves in March 2013. Issue 7 (29th July 2017)

• Record Type: Journal Article
• Authors: Ripoll, J.‐F.; Santolík, O.; Reeves, G. D.; Kurth, W. S.; Denton, M. H.; Loridan, V.; Thaller, S. A.; Kletzing, C. A.; Turner, D. L.
• Is Part Of: Journal of geophysical research. Volume 122:Issue 7(2017)
• Page Start: 7433
• Page End: 7462
• Publication Date: 2017-07-29
• Subjects: whistler mode hiss -- wave particle interactions -- diffusion coefficients -- electron lifetimes -- energy structure -- radiation belts -- MagEIS flux observations -- van Allen probes; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1002/2017JA024139
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: We present simulations of the loss of radiation belt electrons by resonant pitch angle diffusion caused by whistler mode hiss waves for March 2013. Pitch angle diffusion coefficients are computed from the wave properties and the ambient plasma data obtained by the Van Allen Probes with a resolution of 8 h and 0.1 L shell. Loss rates follow a complex dynamic structure, imposed by the wave and plasma properties. Hiss effects can be strong, with minimum lifetimes (of ~1 day) moving from energies of ~100 keV at L ~ 5 up to ~2 MeV at L ~ 2 and stop abruptly, similarly to the observed energy‐dependent inner belt edge. Periods when the plasmasphere extends beyond L ~ 5 favor long‐lasting hiss losses from the outer belt. Such loss rates are embedded in a reduced Fokker‐Planck code and validated against Magnetic Electron and Ion Spectrometer observations of the belts at all energy. Results are complemented with a sensitivity study involving different radial diffusion and lifetime models. Validation is carried out globally at all L shells and energies. The good agreement between simulations and observations demonstrates that hiss waves drive the slot formation during quiet times. Combined with transport, they sculpt the energy structure of the outer belt into an "S shape." Low energy electrons (<0.3 MeV) are less subject to hiss scattering below L = 4. In contrast, 0.3–1.5 MeV electrons evolve in an environment that depopulates them as they migrate from L ~ 5 to L ~ 2.5. Ultrarelativistic electrons are not affected by hiss losses until L ~ 2–3. Key Points: Computations of daily pitch angle diffusion coefficients and electron lifetimes from properties of hiss waves observed in March 2013 Good agreement found between MagEIS flux observations and 1‐D Fokker‐Planck simulations based on our hiss loss term for quiet times Combined with transport, hiss waves loss drives the daily energy structure of the radiation belts, with a typical S‐shaped outer belt