Statistics and Empirical Models of the Plasmasphere Boundaries From the Van Allen Probes for Radiation Belt Physics

Ripoll, J. F.; Thaller, S. A.; Hartley, D. P.; Cunningham, G.; Pierrard, Viviane; Kurth, W. S.; Kletzing, C. A.; Wygant, J. R.

doi:10.1029/2022gl101402

Cited by 15 publications

(18 citation statements)

References 70 publications

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“…The observed number density peak here is ∼4 standard deviations greater than the mean observed density by CRRES in this region. Considering Van Allen Probes measurements, a study of the entire mission by Ripoll et al (2022) found an average number density of ∼800 cm −3 for conditions −90 < Dst < −60 near L = 3.5 on the dusk side, where we show rapid PSD loss. During this event, the enhanced density at this low L* value decreased α* from typical values such that EMIC waves could resonate with multi-MeV electrons, while more typical values may explain why EMIC wave effects are not commonly observed at this low L*.…”

Section: Discussionmentioning

confidence: 73%

On the Dynamics of Ultrarelativistic Electrons (>2 MeV) Near L* = 3.5 During 8 June 2015

Hogan,

Li,

Xiang

et al. 2023

JGR Space Physics

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Understanding local loss processes in Earth’s radiation belts is critical to understanding their overall structure. Electromagnetic ion cyclotron waves can cause rapid loss of multi‐MeV electrons in the radiation belts. These loss effects have been observed at a range of L* values, recently as low as L* = 3.5. Here, we present a case study of an event where a local minimum develops in multi‐MeV electron phase space density (PSD) near L* = 3.5 and evaluate the possibility of electromagnetic ion cyclotron (EMIC) waves in contributing to the observed loss feature. Signatures of EMIC waves are shown including rapid local loss and pitch angle bite outs. Analysis of the wave power spectral density during the event shows EMIC wave occurrence at higher L* values. Using representative wave parameters, we calculate minimum resonant energies, diffusion coefficients, and simulate the evolution of electron PSD during this event. From these results, we find that O+ band EMIC waves could be contributing to the local loss feature during this event. O+ band EMIC waves are uncommon, but do occur in these L* ranges, and therefore may be a significant driver of radiation belt dynamics under certain preconditioning of the radiation belts.

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Section: Discussionmentioning

confidence: 73%

On the Dynamics of Ultrarelativistic Electrons (>2 MeV) Near L* = 3.5 During 8 June 2015

Hogan,

Li,

Xiang

et al. 2023

JGR Space Physics

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“…Due to the strong interactions between energetic particles trapped in the radiation belts and plasmaspheric hiss, the exact position of the plasmapause boundary, as well as the density of the low-energy background particles inside and outside the plasmasphere is critical to know [17]. The EMFISIS and EFW instruments on board Van Allen Probes allowed the deduction of the plasmapause position, as shown in Figure 2 (magenta dots) [8]. When no observations are available, the Space Weather Integrated Forecasting Framework plasmasphere model can be used to determine the position of the plasmapause and the density inside and outside the plasmasphere [18].…”

Section: Discussionmentioning

confidence: 99%

Simultaneous Observations of the June 23, 2015, Intense Storm at Low Earth Orbit and Geostationary Transfer Orbit

2023

RSL

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The electron fluxes in the outer radiation belt during and after the intense geomagnetic storm of June 23, 2015, are investigated both at polar low earth orbit (LEO) and geostationary transfer orbit (GTO). We use the Energetic Particle Telescope (EPT) instrument on board the European Space Agency PROBA-V satellite at LEO at 820 km of altitude and compare simultaneous observations of the Magnetic Electron Ion Spectrometer instrument on board the NASA Van Allen Probes circulating on a low inclination elliptical GTO orbit, ranging from 600 km to 30,600 km. In addition, we use the Electric Field and Waves instrument and the Electric and Magnetic Field Instrument Suite and Integrated Science to compile both the strength of the whistler waves associated to the storm dynamics and the cold electron density of the plasmasphere and plasma trough where the main waveparticle interactions (WPI) occur. From them, we extract mean wave properties to allow WPI and Fokker-Planck computations in a near future. We find that the equatorial trapped electron fluxes observed at GTO are generally higher than at LEO but with magnitudes depending on the energy. Below 1 MeV, maximal fluxes differ by about two orders of magnitude. However, the EPT ultrarelativistic flux (.2.4 MeV) is much lower than the Van Allen Probes flux at 2.33 MeV, by four to five orders of magnitude. During the storm, the dropout and flux increase observed at LEO and GTO present very similar shapes in L and energy versus time but with different intensities.

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“…The majority of banded plasmaspheric hiss events occur in the region L ∼ 2.5-5.0 (Figures 3b-3e) with the largest occurrence rate of ∼8% in the magnetic local time (MLT) sector ∼12-17 (Figures 4g-4i). As the level of geomagnetic activity (denoted by the index AE * on the top) increases, the most probable location of banded plasmaspheric hiss gradually shrinks, and shifts toward the prenoon sector and lower L-shells, which is consistent with the dynamic of the plasmapause (Malaspina et al, 2016;Ripoll et al, 2022). Banded plasmaspheric hiss also occurs with a strong dependence on solar wind dynamic pressure (P dyn ).…”

Section: Spectral Characteristics and Occurrence Pattern Of Banded Pl...mentioning

confidence: 99%

Unique Banded Structures of Plasmaspheric Hiss Waves in the Earth's Magnetosphere

Summers

Xiang

et al. 2023

JGR Space Physics

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We report unambiguous banded signatures of plasmaspheric hiss, uniquely characterized by an upper band above ∼200 Hz, a lower band below ∼100 Hz and a power gap in between • Banded plasmaspheric hiss occurs with the probability ∼8% in the postnoon sector within 2.5-5.0 Earth radii, showing strong dependence on geomagnetic and solar wind conditions • Observations suggest that banded hiss waves result from two combined sources, which however requires further investigation

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Statistics and Empirical Models of the Plasmasphere Boundaries From the Van Allen Probes for Radiation Belt Physics

Cited by 15 publications

References 70 publications

On the Dynamics of Ultrarelativistic Electrons (>2 MeV) Near L* = 3.5 During 8 June 2015

On the Dynamics of Ultrarelativistic Electrons (>2 MeV) Near L* = 3.5 During 8 June 2015

Simultaneous Observations of the June 23, 2015, Intense Storm at Low Earth Orbit and Geostationary Transfer Orbit

Unique Banded Structures of Plasmaspheric Hiss Waves in the Earth's Magnetosphere

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