Bibliography



Found 6 entries in the Bibliography.


Showing entries from 1 through 6


2021

On the estimation of the ratio of ULF wave electric fields in space and the magnetic fields at the ground.

Abstract Three new methods for estimating a ratio of the ultra-low frequency (ULF; 1–100 mHz) wave equatorial electric field amplitude in the Earth’s magnetosphere to ground magnetic field amplitudes for field line resonances are described. These methods use ratios of the time series extrema, ratios of the envelope waveform and the ratio of the spectral amplitude at the field line resonance frequency. These methods were applied to four ULF resonance intervals; three detected by the Van Allen Probe A spacecraft and one de ...

Warden, L.; Waters, C.; Sciffer, M.; Hull, A.;

YEAR: 2021     DOI: https://doi.org/10.1029/2020JA029052

remote sensing; ULF plasma waves; Van Allen Probes; estimation; equatorial electric fields

2020

Correlations Between Dispersive Alfvén Wave Activity, Electron Energization, and Ion Outflow in the Inner Magnetosphere

Using measurements from the Van Allen Probes, we show that field-aligned fluxes of electrons energized by dispersive Alfvén waves (DAWs) are prominent in the inner magnetosphere during active conditions. These electrons have preferentially field-aligned anisotropies from 1.2 to >2 at energies ranging from tens of electron volts to several kiloelectron volts (keV), with largest values being coincident with magnetic field dipolarizations. Comparisons reveal that DAW energy densities and Poynting fluxes are strongly correlated ...

Hull, A.; Chaston, C.; Bonnell, J.; Damiano, P.; Wygant, J.; Reeves, G.;

YEAR: 2020     DOI: https://doi.org/10.1029/2020GL088985

dispersive Alfvén waves; field-aligned electrons; inner magnetosphere; oxygen ion outflow; Geomagnetic storms; substorms; Van Allen Probes

Episodic Occurrence of Field-Aligned Energetic Ions on the Dayside

The tens of kiloelectron volt ions observed in the ring current region at L ~ 3\textendash7 generally have pancake pitch angle distributions, that is, peaked at 90\textdegree. However, in this study, by using the Van Allen Probe observations on the dayside, unexpectedly, we have found that about 5\% time, protons with energies of ~30 to 50 keV show two distinct populations, having an additional field-aligned population overlapping with the original pancake population. The newly appearing field-aligned populations have higher ...

Yue, Chao; Bortnik, Jacob; Zou, Shasha; Nishimura, Yukitoshi; Foster, John; Coppeans, Thomas; Ma, Qianli; Zong, Qiugang; Hull, A.; Henderson, Mike; Reeves, Geoffrey; Spence, Harlan;

YEAR: 2020     DOI: 10.1029/2019GL086384

Van Allen Probes

2018

Electron Distributions in Kinetic Scale Field Line Resonances: A Comparison of Simulations and Observations

Observations in kinetic scale field line resonances, or eigenmodes of the geomagnetic field, reveal highly field-aligned plateaued electron distributions. By combining observations from the Van Allen Probes and Cluster spacecraft with a hybrid kinetic gyrofluid simulation we show how these distributions arise from the nonlocal self-consistent interaction of electrons with the wavefield. This interaction is manifested as electron trapping in the standing wave potential. The process operates along most of the field line and qu ...

Damiano, P.A.; Chaston, C.C.; Hull, A.J.; Johnson, J.R.;

YEAR: 2018     DOI: 10.1029/2018GL077748

Alfven waves; field line resonances; kinetic effects; numerical modeling; particle trapping; Radiation belts; Van Allen Probes

Reply to Comment by Nishimura Et Al.

Nishimura et al. (2010, https://doi.org/10.1126/science.1193186, 2011, https://doi.org/10.1029/2011JA016876, 2013, https://doi.org/10.1029/2012JA018242, and in their comment, hereafter called N18) have suggested that chorus waves interact with equatorial electrons to produce pulsating auroras. We agree that chorus can scatter electrons >10 keV, as do Time Domain Structures (TDSs). Lower-energy electrons occurring in pulsating auroras cannot be produced by chorus, but such electrons are scattered and accelerated by TDS. TDSs ...

Mozer, F.; Hull, A.; Lejosne, S.; . Y. Vasko, I;

YEAR: 2018     DOI: 10.1002/2018JA025218

chorus cannot precipitate electrons observed in pulsating auroras; time domain structures cause electron precipitation in pulsating auroras; Van Allen Probes

2017

Pulsating auroras produced by interactions of electrons and time domain structures

Previous evidence has suggested that either lower band chorus waves or kinetic Alfven waves scatter equatorial kilovolt electrons that propagate to lower altitudes where they precipitate or undergo further low-altitude scattering to make pulsating auroras. Recently, time domain structures (TDSs) were shown, both theoretically and experimentally, to efficiently scatter equatorial electrons. To assess the relative importance of these three mechanisms for production of pulsating auroras, 11 intervals of equatorial THEMIS data a ...

Mozer, F.; Agapitov, O.; Hull, A.; Lejosne, S.; . Y. Vasko, I;

YEAR: 2017     DOI: 10.1002/2017JA024223

pulsating auroras; Van Allen Probes; wave scattering



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