Gradual diffusion and punctuated phase space density enhancements of highly relativistic electrons: Van Allen Probes observations

Baker, D. N.; Jaynes, Allison; Li, X.; Henderson, M. G.; Kanekal, S. G.; Reeves, G. D.; Spence, Harlan E.; Claudepierre, S. G.; Fennell, J. F.; Hudson, M. K.; Thorne, R. M.; Foster, J. C.; Erickson, P. J.; Malaspina, D.; Wygant, J. R.; Boyd, A. J.; Kletzing, C. A.; Drozdov, Alexander; Shprits, Y. Y.

doi:10.1002/2013gl058942

Cited by 137 publications

(183 citation statements)

References 31 publications

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“…This event was detected by different space weather dedicated satellites such as the Van Allen Probes which monitor the electron particle dynamics in the Earth's radiation belt. From these data, it appears that the plasmapause boundary was forced deeply inward within the magnetosphere implying high aurora electrojet index and a recovery phase of the storm on March 18 at 03:00 UTC (Foster et al 2014;Baker et al 2014;Boyd et al 2014) which is concordant with ROB-TEC observations.…”

Section: Discussionsupporting

confidence: 79%

Near real-time ionospheric monitoring over Europe at the Royal Observatory of Belgium using GNSS data

Bergeot

Chevalier

Bruyninx

et al. 2014

J. Space Weather Space Clim.

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Various scientific applications and services increasingly demand real-time information on the effects of space weather on Earth's atmosphere. In this frame, the Royal Observatory of Belgium (ROB) takes advantage of the dense EUREF Permanent GNSS Network (EPN) to monitor the ionosphere over Europe from the measured delays in the GNSS signals, and provides publicly several derived products. The main ROB products consist of ionospheric vertical Total Electron Content (TEC) maps over Europe and their variability estimated in near real-time every 15 min on 0.5°· 0.5°grids using GPS observations. The maps are available online with a latency of~3 min in IONEX format at ftp://gnss.oma.be and as interactive web pages at www.gnss.be. This paper presents the method used in the ROB-IONO software to generate the maps. The ROB-TEC maps show a good agreement with widely used post-processed products such as IGS and ESA with mean differences of 1.3 ± 0.9 and 0.4 ± 1.6 TECu respectively for the period 2012 to mid-2013. In addition, we tested the reliability of the ROB-IONO software to detect abnormal ionospheric activity during the Halloween 2003 ionospheric storm. For this period, the mean differences with IGS and ESA maps are 0.9 ± 2.2 and 0.6 ± 6.8 TECu respectively with maximum differences (>38 TECu) occurring during the major phase of the storm. These differences are due to the lower resolution in time and space of both IGS and ESA maps compared to the ROB-TEC maps. A description of two recent events, one on March 17, 2013 and one on February 27, 2014 also highlights the capability of the method adopted in the ROB-IONO software to detect in near real-time abnormal ionospheric behaviour over Europe. In that frame, ROB maintains a data base publicly available with identified ionospheric events since 2012.

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Section: Discussionsupporting

confidence: 79%

Near real-time ionospheric monitoring over Europe at the Royal Observatory of Belgium using GNSS data

Bergeot

Chevalier

Bruyninx

et al. 2014

J. Space Weather Space Clim.

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“…4). Unless there occurs a prompt interplanetary-shock-induced acceleration like the March 1991 event 21 , we would favour a local wave acceleration process that occurs just outside the plasmapause 8,22 when the plasmapause is pushed into the lower-L region.…”

Section: Letter Researchmentioning

confidence: 97%

An impenetrable barrier to ultrarelativistic electrons in the Van Allen radiation belts

Baker

Jaynes

Hoxie

et al. 2014

Nature

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174

184

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Early observations indicated that the Earth's Van Allen radiation belts could be separated into an inner zone dominated by high-energy protons and an outer zone dominated by high-energy electrons. Subsequent studies showed that electrons of moderate energy (less than about one megaelectronvolt) often populate both zones, with a deep 'slot' region largely devoid of particles between them. There is a region of dense cold plasma around the Earth known as the plasmasphere, the outer boundary of which is called the plasmapause. The two-belt radiation structure was explained as arising from strong electron interactions with plasmaspheric hiss just inside the plasmapause boundary, with the inner edge of the outer radiation zone corresponding to the minimum plasmapause location. Recent observations have revealed unexpected radiation belt morphology, especially at ultrarelativistic kinetic energies (more than five megaelectronvolts). Here we analyse an extended data set that reveals an exceedingly sharp inner boundary for the ultrarelativistic electrons. Additional, concurrently measured data reveal that this barrier to inward electron radial transport does not arise because of a physical boundary within the Earth's intrinsic magnetic field, and that inward radial diffusion is unlikely to be inhibited by scattering by electromagnetic transmitter wave fields. Rather, we suggest that exceptionally slow natural inward radial diffusion combined with weak, but persistent, wave-particle pitch angle scattering deep inside the Earth's plasmasphere can combine to create an almost impenetrable barrier through which the most energetic Van Allen belt electrons cannot migrate.

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“…Spacecraft observations suggest that the main region of relativistic electron acceleration is located around L ∼ 5, where a localized maximum of energetic electron fluxes has often been registered (Selesnick and Blake 2000;Chen et al 2007;Baker et al 2014). Thus, a good description of the outer-belt region roughly bounded by the plasmapause and the geostationary orbit is of primary importance.…”

Section: Empirical Models Of Wave Intensity and Obliquitymentioning

confidence: 99%

Oblique Whistler-Mode Waves in the Earth’s Inner Magnetosphere: Energy Distribution, Origins, and Role in Radiation Belt Dynamics

et al. 2016

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International audienceIn this paper we review recent spacecraft observations of oblique whistler-mode waves in the Earth’s inner magnetosphere as well as the various consequences of the presence of such waves for electron scattering and acceleration. In particular, we survey the statistics of occurrences and intensity of oblique chorus waves in the region of the outer radiation belt, comprised between the plasmapause and geostationary orbit, and discuss how their actual distribution may be explained by a combination of linear and non-linear generation, propagation, and damping processes. We further examine how such oblique wave populations can be included into both quasi-linear diffusion models and fully nonlinear models of wave-particle interaction. On this basis, we demonstrate that varying amounts of oblique waves can significantly change the rates of particle scattering, acceleration, and precipitation into the atmosphere during quiet times as well as in the course of a storm. Finally, we discuss possible generation mechanisms for such oblique waves in the radiation belts. We demonstrate that oblique whistler-mode chorus waves can be considered as an important ingredient of the radiation belt system and can play a key role in many aspects of wave-particle resonant interactions

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Gradual diffusion and punctuated phase space density enhancements of highly relativistic electrons: Van Allen Probes observations

Cited by 137 publications

References 31 publications

Near real-time ionospheric monitoring over Europe at the Royal Observatory of Belgium using GNSS data

Near real-time ionospheric monitoring over Europe at the Royal Observatory of Belgium using GNSS data

An impenetrable barrier to ultrarelativistic electrons in the Van Allen radiation belts

Oblique Whistler-Mode Waves in the Earth’s Inner Magnetosphere: Energy Distribution, Origins, and Role in Radiation Belt Dynamics

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