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Van Allen Probes Bibliography is from August 2012 through September 2021
Found 15 entries in the Bibliography.
Showing entries from 1 through 15
On the Formation of Phantom Electron Phase Space Density Peaks in Single Spacecraft Radiation Belt Data
Abstract This paper examines the rapid losses and acceleration of trapped relativistic and ultrarelativistic electron populations in the Van Allen radiation belt during the September 7-9, 2017, geomagnetic storm. By analyzing the dynamics of the last closed drift shell (LCDS) and the electron flux and phase space density (PSD), we show that the electron dropouts are consistent with magnetopause shadowing and outward radial diffusion to the compressed LCDS. During the recovery phase an in-bound pass of Van Allen Probe A shows ...
Olifer, L.; Mann, I.; Ozeke, L.; Morley, S.; Louis, H.;
Published by: Geophysical Research Letters Published on: 05/2021
YEAR: 2021   DOI: https://doi.org/10.1029/2020GL092351
Van Allen Probes; magnetopause shadowing; ULF wave radial diffusion; electron phase space density
ULF Wave Driven Radial Diffusion During Geomagnetic Storms: A statistical analysis of Van Allen Probes observations
Abstract The impact of radial diffusion in storm time radiation belt dynamics is well-debated. In this study we quantify the changes and variability in radial diffusion coefficients during geomagnetic storms. A statistical analysis of Van Allen Probes data (2012 − 2019) is conducted to obtain measurements of the magnetic and electric power spectral densities for Ultra Low Frequency (ULF) waves, and corresponding radial diffusion coefficients. The results show global wave power enhancements occur during the storm main phase ...
Sandhu, J.; Rae, I.; Wygant, J.; Breneman, A.; Tian, S.; Watt, C.; Horne, R.; Ozeke, L.; Georgiou, M.; Walach, M.-T.;
Published by: Journal of Geophysical Research: Space Physics Published on: 03/2021
YEAR: 2021   DOI: https://doi.org/10.1029/2020JA029024
ULF waves; radial diffusion; outer radiation belt; Van Allen Probes; Geomagnetic storms
Detection of Hertz Frequency Multiharmonic Field Line Resonances at Low-L (L = 1.1–1.5) During Van Allen Probe Perigee Passes
We present new and previously unreported in situ observations of Hertz frequency multiharmonic mode field line resonances detected by the Electric Field and Waves instrument on-board the NASA Van Allen probes during low-L perigee passes. Spectral analysis of the spin-plane electric field data reveals the waves in numerous perigee passes, in sequential passes of probes A and B, and with harmonic frequency structures from ∼0.5 to 3.5 Hz which vary with L-shell, altitude, and from day-to-day. Comparing the observations to wa ...
Lena, F.; Ozeke, L.; Wygant, J.; Tian, S.; Breneman, A.; Mann, I.;
Published by: Geophysical Research Letters Published on: 12/2020
YEAR: 2020   DOI: https://doi.org/10.1029/2020GL090632
Field line resonance; Ionosphere; magneto-seismology; Magnetosphere; plasmasphere; standing Alfvén waves; Van Allen Probes
Reply to \textquoterightThe dynamics of Van Allen belts revisited\textquoteright
Mann, I.; Ozeke, L.; Morley, S.; Murphy, K.; Claudepierre, S.; Turner, D.; Baker, D.; Rae, I.; Kale, A.; Milling, D.; Boyd, A.; Spence, H.; Singer, H.; Dimitrakoudis, S.; Daglis, I.; Honary, F.;
Published by: Nature Physics Published on: 02/2019
YEAR: 2019   DOI: 10.1038/nphys4351
The March 2015 Superstorm Revisited: Phase Space Density Profiles and Fast ULF Wave Diffusive Transport
We present the temporal evolution of electron Phase Space Density (PSD) in the outer radiation belt during the intense March 2015 geomagnetic storm. Comparing observed PSD profiles as a function of L* at fixed first, M, and second, K, adiabatic invariants with those produced by simulations is critical for determining the physical processes responsible for the outer radiation belt dynamics. Here we show that the bulk of the accelerated and enhanced outer radiation belt population consists of electrons with K < 0.17 G1/2Re. Fo ...
Ozeke, L.; Mann, I.; Claudepierre, S.; Henderson, M.; Morley, S.; Murphy, K.; Olifer, L.; Spence, H.; Baker, D.;
Published by: Journal of Geophysical Research: Space Physics Published on: 01/2019
YEAR: 2019   DOI: 10.1029/2018JA026326
Local Acceleration; March 2015 storm; Phase space density; radial diffusion; Radiation belt; ULF waves; Van Allen Probes
On the role of last closed drift shell dynamics in driving fast losses and Van Allen radiation belt extinction
We present observations of very fast radiation belt loss as resolved using high-time resolution electron flux data from the constellation of Global Positioning System (GPS) satellites. The timescale of these losses is revealed to be as short as \~0.5 - 2 hours during intense magnetic storms, with some storms demonstrating almost total loss on these timescales and which we characterize as radiation belt extinction. The intense March 2013 and March 2015 storms both show such fast extinction, with a rapid recovery, while the Se ...
Olifer, L.; Mann, I.; Morley, S.; Ozeke, L.; Choi, D.;
Published by: Journal of Geophysical Research: Space Physics Published on: 04/2018
YEAR: 2018   DOI: 10.1029/2018JA025190
inner magnetosphere; magnetopause shadowing; Radiation belts; Van Allen Probes
Quantitative Evaluation of Radial Diffusion and Local Acceleration Processes During GEM Challenge Events
We simulate the radiation belt electron flux enhancements during selected Geospace Environment Modeling (GEM) challenge events to quantitatively compare the major processes involved in relativistic electron acceleration under different conditions. Van Allen Probes observed significant electron flux enhancement during both the storm time of 17\textendash18 March 2013 and non\textendashstorm time of 19\textendash20 September 2013, but the distributions of plasma waves and energetic electrons for the two events were dramaticall ...
Ma, Q.; Li, W.; Bortnik, J.; Thorne, R.; Chu, X.; Ozeke, L.; Reeves, G.; Kletzing, C.; Kurth, W.; Hospodarsky, G.; Engebretson, M.; Spence, H.; Baker, D.; Blake, J.; Fennell, J.; Claudepierre, S.;
Published by: Journal of Geophysical Research: Space Physics Published on: 03/2018
YEAR: 2018   DOI: 10.1002/2017JA025114
electron accelerationl whistler mode waves; radial diffusion; radiation belt simulation; Van Allen Probes; Van Allen Probes observation
Ultra-relativistic radiation belt extinction and ULF wave radial diffusion: Modeling the September 2014 extended dropout event
In September 2014 an unusually long-lasting (≳10 days) ultra-relativistic electron flux depletion occurred in the outer radiation belt despite ongoing solar wind forcing. We simulate this period using a ULF wave radial diffusion model, driven by observed ULF wave power coupled to flux variations at the outer boundary at L* = 5, including empirical electron loss models due to chorus and hiss wave scattering. Our results show that unexplained rapid main phase loss, that depletes the belt within hours, is essential to explain ...
Ozeke, Louis; Mann, Ian; Murphy, Kyle; Sibeck, David; Baker, Daniel;
Published by: Geophysical Research Letters Published on: 03/2017
YEAR: 2017   DOI: 10.1002/2017GL072811
radial diffusion; Radiation belt; ULF waves; ultrarelativistic; Van Allen Probes; wave-particle interactions
Explaining the dynamics of the ultra-relativistic third Van Allen radiation belt
Since the discovery of the Van Allen radiation belts over 50 years ago, an explanation for their complete dynamics has remained elusive. Especially challenging is understanding the recently discovered ultra-relativistic third electron radiation belt. Current theory asserts that loss in the heart of the outer belt, essential to the formation of the third belt, must be controlled by high-frequency plasma wave\textendashparticle scattering into the atmosphere, via whistler mode chorus, plasmaspheric hiss, or electromagnetic ion ...
Mann, I.; Ozeke, L.; Murphy, K.; Claudepierre, S.; Turner, D.; Baker, D.; Rae, I.; Kale, A.; Milling, D.; Boyd, A.; Spence, H.; Reeves, G.; Singer, H.; Dimitrakoudis, S.; Daglis, I.; Honary, F.;
Published by: Nature Physics Published on: 06/2016
YEAR: 2016   DOI: 10.1038/nphys3799
Astrophysical plasmas; Magnetospheric physics; Van Allen Probes
How quickly, how deeply, and how strongly can dynamical outer boundary conditions impact Van Allen radiation belt morphology?
Here we examine the speed, strength, and depth of the coupling between dynamical variations of ultrarelativistic electron flux at the outer boundary and that in the heart of the outer radiation belt. Using ULF wave radial diffusion as an exemplar, we show how changing boundary conditions can completely change belt morphology even under conditions of identical wave power. In the case of ULF wave radial diffusion, the temporal dynamics of a new source population or a sink of electron flux at the outer plasma sheet boundary can ...
Published by: Journal of Geophysical Research: Space Physics Published on: 06/2016
YEAR: 2016   DOI: 10.1002/jgra.v121.610.1002/2016JA022647
Magnetic field power spectra and magnetic radial diffusion coefficients using CRRES magnetometer data
We used the fluxgate magnetometer data from Combined Release and Radiation Effects Satellite (CRRES) to estimate the power spectral density (PSD) of the compressional component of the geomagnetic field in the \~1 mHz to \~8 mHz range. We conclude that magnetic wave power is generally higher in the noon sector for quiet times with no significant difference between the dawn, dusk, and the midnight sectors. However, during high Kp activity, the noon sector is not necessarily dominant anymore. The magnetic PSDs have a very disti ...
Ali, Ashar; Elkington, Scot; Tu, Weichao; Ozeke, Louis; Chan, Anthony; Friedel, Reiner;
Published by: Journal of Geophysical Research: Space Physics Published on: 02/2015
YEAR: 2015   DOI: 10.1002/2014JA020419
A ULF wave driver of ring current energization
ULF wave radial diffusion plays an important role in the transport of energetic electrons in the outer radiation belt, yet similar ring current transport is seldom considered even though ions satisfy a nearly identical drift resonance condition albeit without the relativistic correction. By examining the correlation between ULF wave power and the response of the ring current, characterized by Dst, we demonstrate a definite correlation between ULF wave power and Dst. Significantly, the lagged correlation peaks such that ULF w ...
Murphy, Kyle; Mann, Ian; Ozeke, Louis;
Published by: Geophysical Research Letters Published on: 10/2014
YEAR: 2014   DOI: 10.1002/grl.v41.1910.1002/2014GL061253
Dst; radial diffusion; ring current dynamics; ULF waves; wave particle interactions
Modeling cross L shell impacts of magnetopause shadowing and ULF wave radial diffusion in the Van Allen belts
We present simulations of the outer electron radiation belt using a new ULF wave-driven radial diffusion model, including empirical representations of loss due to chorus and plasmaspheric hiss. With an outer boundary condition constrained by in situ electron flux observations, we focus on the impacts of magnetopause shadowing and outward radial diffusion in the heart of the radiation belt. Third invariant conserving solutions are combined to simulate the L shell and time dependence of the differential flux at a fixed energy. ...
Ozeke, Louis; Mann, Ian; Turner, Drew; Murphy, Kyle; Degeling, Alex; Rae, Jonathan; Milling, David;
Published by: Geophysical Research Letters Published on: 10/2014
YEAR: 2014   DOI: 10.1002/2014GL060787
magnetopause shadowing; Radiation belt; ULF wave radial diffusion
Analytic expressions for ULF wave radiation belt radial diffusion coefficients
We present analytic expressions for ULF wave-derived radiation belt radial diffusion coefficients, as a function of L and Kp, which can easily be incorporated into global radiation belt transport models. The diffusion coefficients are derived from statistical representations of ULF wave power, electric field power mapped from ground magnetometer data, and compressional magnetic field power from in situ measurements. We show that the overall electric and magnetic diffusion coefficients are to a good approximation both indepen ...
Ozeke, Louis; Mann, Ian; Murphy, Kyle; Rae, Jonathan; Milling, David;
Published by: Journal of Geophysical Research: Space Physics Published on: 03/2014
YEAR: 2014   DOI: 10.1002/2013JA019204
Discovery of the action of a geophysical synchrotron in the Earth\textquoterights Van Allen radiation belts
Although the Earth\textquoterights Van Allen radiation belts were discovered over 50 years ago, the dominant processes responsible for relativistic electron acceleration, transport and loss remain poorly understood. Here we show evidence for the action of coherent acceleration due to resonance with ultra-low frequency waves on a planetary scale. Data from the CRRES probe, and from the recently launched multi-satellite NASA Van Allen Probes mission, with supporting modeling, collectively show coherent ultra-low frequency inte ...
Mann, Ian; Lee, E.; Claudepierre, S.; Fennell, J.; Degeling, A.; Rae, I.; Baker, D.; Reeves, G.; Spence, H.; Ozeke, L.; Rankin, R.; Milling, D.; Kale, A.; Friedel, R.; Honary, F.;
Published by: Nature Communications Published on: 11/2013
YEAR: 2013   DOI: 10.1038/ncomms3795