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Authors: Fuselier S. A., Lewis W. S., Schiff C., Ergun R., Burch J L, et al.
Title: Magnetospheric Multiscale Science Mission Profile and Operations
Abstract: The Magnetospheric Multiscale (MMS) mission and operations are designed to provide the maximum reconnection science. The mission phases are chosen to investigate reconnection at the dayside magnetopause and in the magnetotail. At the dayside, the MMS orbits are chosen to maximize encounters with the magnetopause in regions where the probability of encountering the reconnection diffusion region is high. In the magnetotail, the orbits are chosen to maximize encounters with the neutral sheet, where reconnection is known to occur episodically. Although this targeting is limited by engineering constraints such as total available fuel, high science return orbits exist for launch dates over most of the year. The tetrahedral spacecraft formation has variable spacing to determine the optimum se. . .
Date: 09/2014 Publisher: Space Science Reviews DOI: 10.1007/s11214-014-0087-x Available at: http://link.springer.com/content/pdf/10.1007/s11214-014-0087-x
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Authors: Funsten H O, Skoug R M, Guthrie A A, MacDonald E A, Baldonado J R, et al.
Title: Helium, Oxygen, Proton, and Electron (HOPE) Mass Spectrometer for the Radiation Belt Storm Probes Mission
Abstract: The HOPE mass spectrometer of the Radiation Belt Storm Probes (RBSP) mission (renamed the Van Allen Probes) is designed to measure the in situ plasma ion and electron fluxes over 4π sr at each RBSP spacecraft within the terrestrial radiation belts. The scientific goal is to understand the underlying physical processes that govern the radiation belt structure and dynamics. Spectral measurements for both ions and electrons are acquired over 1 eV to 50 keV in 36 log-spaced steps at an energy resolution ΔE FWHM/E≈15 %. The dominant ion species (H+, He+, and O+) of the magnetosphere are identified using foil-based time-of-flight (TOF) mass spectrometry with channel electron multiplier (CEM) detectors. Angular measurements are derived using five polar pixels coplanar with the spacecraft spin. . .
Date: 08/2013 Publisher: Space Science Reviews DOI: 10.1007/s11214-013-9968-7 Available at: http://link.springer.com/article/10.1007%2Fs11214-013-9968-7
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Authors: Fu Xiangrong, Gary Peter, Reeves Geoffrey D, Winske Dan, and Woodroffe Jesse R.
Title: Generation of Highly Oblique Lower-band Chorus via Nonlinear Three-wave Resonance
Abstract: Chorus in the inner magnetosphere has been observed frequently at geomagnetically active times, typically exhibiting a two-band structure with a quasi-parallel lower-band and an upper-band with a broad range of wave normal angles. But recent observations by Van Allen Probes confirm another type of lower-band chorus, which has a large wave normal angle close to the resonance cone angle. It has been proposed that these waves could be generated by a low-energy beam-like electron component or by temperature anisotropy of keV electrons in the presence of a low-energy plateau-like electron component. This paper, however, presents an alternative mechanism for generation of this highly oblique lower-band chorus. Through a nonlinear three-wave resonance, a quasi-parallel lower-band chorus wave can . . .
Date: 09/2017 Publisher: Geophysical Research Letters DOI: 10.1002/2017GL074411 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017GL074411/full
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Authors: Fu Xiangrong, Guo Zehua, Dong Chuanfei, and Gary Peter
Title: Nonlinear subcyclotron resonance as a formationmechanism for gaps in banded chorus
Abstract: An interesting characteristic of magnetospheric chorus is the presence of a frequency gap at ω≃0.5Ωe, where Ωe is the electron cyclotron angular frequency. Recent chorus observations sometimes show additional gaps near 0.3Ωe and 0.6Ωe. Here we present a novel nonlinear mechanism for the formation of these gaps using Hamiltonian theory and test particle simulations in a homogeneous, magnetized, collisionless plasma. We find that an oblique whistler wave with frequency at a fraction of the electron cyclotron frequency can resonate with electrons, leading to effective energy exchange between the wave and particles.
Date: 05/2015 Publisher: Geophysical Research Letters DOI: 10.1002/2015GL064182 Available at: http://doi.wiley.com/10.1002/2015GL064182
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Authors: Fu H. S., Cao J. B., Zhima Z., Khotyaintsev Y. V., Angelopoulos V, et al.
Title: First observation of rising-tone magnetosonic waves
Abstract: Magnetosonic (MS) waves are linearly polarized emissions confined near the magnetic equator with wave normal angle near 90° and frequency below the lower hybrid frequency. Such waves, also termed equatorial noise, were traditionally known to be “temporally continuous” in their time-frequency spectrogram. Here we show for the first time that MS waves actually have discrete wave elements with rising-tone features in their spectrogram. The frequency sweep rate of MS waves, ~1 Hz/s, is between that of chorus and electromagnetic ion cyclotron (EMIC) waves. For the two events we analyzed, MS waves occur outside the plasmapause and cannot penetrate into the plasmasphere; their power is smaller than that of chorus. We suggest that the rising-tone feature of MS waves is a consequence of nonl. . .
Date: 11/2014 Publisher: Geophysical Research Letters Pages: 7419 - 7426 DOI: 10.1002/grl.v41.2110.1002/2014GL061867 Available at: http://doi.wiley.com/10.1002/grl.v41.21http://doi.wiley.com/10.1002/2014GL061867
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Authors: Fu Xiangrong, Cowee Misa M., Friedel Reinhard H., Funsten Herbert O, Gary Peter, et al.
Title: Whistler Anisotropy Instabilities as the Source of Banded Chorus: Van Allen Probes Observations and Particle-in-Cell Simulations
Abstract: Magnetospheric banded chorus is enhanced whistler waves with frequencies ωr < Ωe, where Ωe is the electron cyclotron frequency, and a characteristic spectral gap at ωr ≃ Ωe/2. This paper uses spacecraft observations and two-dimensional particle-in-cell (PIC) simulations in a magnetized, homogeneous, collisionless plasma to test the hypothesis that banded chorus is due to local linear growth of two branches of the whistler anisotropy instability excited by two distinct, anisotropic electron components of significantly different temperatures. The electron densities and temperatures are derived from HOPE instrument measurements on the Van Allen Probes A satellite during a banded chorus event on 1 November 2012. The observations are consistent with a three-component electron mod. . .
Date: 10/2014 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020364 Available at: http://doi.wiley.com/10.1002/2014JA020364
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Authors: Fox N. J., and Burch J. L.
Title: The Van Allen Probes Mission
Abstract: N/A
Date: Publisher: Springer Pages: 646 DOI: N/A Available at: http://www.springer.com/astronomy/extraterrestrial+physics,+space+sciences/book/978-1-4899-7432-7
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Authors: Fox N J, and Burch J L
Title: Preface
Abstract: The discovery of the Van Allen radiation belts in 1958, starting with data from the United States’ first two successful orbiting spacecraft, Explorer’s I and III, was an astounding surprise and represented the founding of what we now call magnetospheric physics. Since that time many spacecraft have traversed the radiation belts en route to other more distant parts of Earth’s magnetosphere and other worlds beyond Earth’s orbit. After initial climatological models of the radiation belts were obtained in the 1960’s and early 1970’s, the main concern about them was the ability of spacecraft and astronauts to survive their intense radiation. And yet there were true scientific mysteries to be solved, glimpses of which came in the 1990’s from spacecraft like CRRES and SAMPEX. CRRES . . .
Date: 11/2013 Publisher: Space Science Reviews Pages: 1-2 DOI: 10.1007/s11214-013-9997-2 Available at: http://link.springer.com/article/10.1007%2Fs11214-013-9997-2
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Authors: Foster J. C., Erickson P. J., Coster A. J., Thaller S., Tao J., et al.
Title: Storm time observations of plasmasphere erosion flux in the magnetosphere and ionosphere
Abstract: Plasmasphere erosion carries cold dense plasma of ionospheric origin in a storm-enhanced density plume extending from dusk toward and through the noontime cusp and dayside magnetopause and back across polar latitudes in a polar tongue of ionization. We examine dusk sector (20 MLT) plasmasphere erosion during the 17 March 2013 storm (Dst ~ −130 nT) using simultaneous, magnetically aligned direct sunward ion flux observations at high altitude by Van Allen Probes RBSP-A (at ~3.0 Re) and at ionospheric heights (~840 km) by DMSP F-18. Plasma erosion occurs at both high and low altitudes where the subauroral polarization stream flow overlaps the outer plasmasphere. At ~20 UT, RBSP-A observed ~1.2E12 m−2 s−1 erosion flux, while DMSP F-18 observed ~2E13 m−2 s−1 sunward flux. We. . .
Date: 02/2014 Publisher: Geophysical Research Letters Pages: 762 - 768 DOI: 10.1002/2013GL059124 Available at: http://doi.wiley.com/10.1002/2013GL059124
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Authors: Foster J C
Title: Imaging the plasmasphere with ground based GPS TEC observations and comparisons with in situ plasmaspheric observations with Van Allen Probes
Abstract: For over a decade, incoherent scatter radar observations of the mid and auroral-latitude ionosphere combined with ground based GPS observations of total electron content (TEC) have been used to study the intense storm enhanced density (SED) plumes that form over the Americas during major geomagnetic storms [1]. Magnetic field mapping of the ionospheric observations to magnetospheric heights revealed close correspondence between the SED and plasmasphere erosion plumes observed from space in EUV imagery by the IMAGE satellite [2]. During the current solar cycle the global distribution of GPS receivers used in creating the TEC maps and movies has increased significantly providing near-continuous two-dimensional coverage of TEC morphology and dynamics over much the northern hemisphere mid and . . .
Date: 08/2014 Publisher: IEEE DOI: 10.1109/URSIGASS.2014.6929943 Available at: http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6929943
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Authors: Foster John C, and Erickson Philip J.
Title: Initial observations of plasma waves in the sub-auroral polarization stream with the Van Allen Probes
Abstract: The Sub-Auroral Polarization Stream (SAPS) is a geospace boundary layer phenomenon associated with the interaction of the warm plasma of the magnetospheric ring current with the cold ions and electrons of the outer plasmasphere [1]. Driven by ring current enhancements during magnetospheric disturbances, SAPS location, intensity, and characteristics are greatly influenced by the underlying ionosphere. Strong M-I coupling by means of field-aligned currents creates a high-speed (>1000 m/s) westward plasma flow channel in the ionosphere at pre-midnight/post-noon local times which is readily observable by incoherent scatter [2] and HF radars and in plasma drift observations by low-altitude spacecraft (e.g. DMSP). The fast ionospheric flows generate E-region irregularities providing for addition. . .
Date: 08/2014 Publisher: IEEE DOI: 10.1109/URSIGASS.2014.6929852 Available at: http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6929852
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Authors: Foster J. C., Erickson P. J., Baker D N, Claudepierre S G, Kletzing C A, et al.
Title: Prompt energization of relativistic and highly relativistic electrons during a substorm interval: Van Allen Probes observations
Abstract: On 17 March 2013, a large magnetic storm significantly depleted the multi-MeV radiation belt. We present multi-instrument observations from the Van Allen Probes spacecraft Radiation Belt Storm Probe A and Radiation Belt Storm Probe B at ~6 Re in the midnight sector magnetosphere and from ground-based ionospheric sensors during a substorm dipolarization followed by rapid reenergization of multi-MeV electrons. A 50% increase in magnetic field magnitude occurred simultaneously with dramatic increases in 100 keV electron fluxes and a 100 times increase in VLF wave intensity. The 100 keV electrons and intense VLF waves provide a seed population and energy source for subsequent radiation belt enhancements. Highly relativistic (>2 MeV) electron fluxes increased immediately at L* ~ 4.5. . .
Date: 01/2014 Publisher: Geophysical Research Letters Pages: 20 - 25 DOI: 10.1002/2013GL058438 Available at: http://doi.wiley.com/10.1002/2013GL058438
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Authors: Foster J. C., Erickson P. J., Omura Y., Baker D. N., Kletzing C. A., et al.
Title: Van Allen Probes observations of prompt MeV radiation belt electron acceleration in nonlinear interactions with VLF chorus
Abstract: Prompt recovery of MeV (millions of electron Volts) electron populations in the poststorm core of the outer terrestrial radiation belt involves local acceleration of a seed population of energetic electrons in interactions with VLF chorus waves. Electron interactions during the generation of VLF rising tones are strongly nonlinear, such that a fraction of the relativistic electrons at resonant energies are trapped by waves, leading to significant nonadiabatic energy exchange. Through detailed examination of VLF chorus and electron fluxes observed by Van Allen Probes, we investigate the efficiency of nonlinear processes for acceleration of electrons to MeV energies. We find through subpacket analysis of chorus waveforms that electrons with initial energy of hundreds of keV to 3 MeV can be a. . .
Date: 01/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023429 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA023429
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Authors: Foster John C, and Erickson Philip J.
Title: Prompt energization of relativistic and highly relativistic electrons during a substorm interval
Abstract: On 17 March 2013, a large magnetic storm significantly depleted the multi-MeV radiation belt. We present multi-instrument observations from the Van Allen Probes spacecraft Radiation Belt Storm Probe A and Radiation Belt Storm Probe B at ∼6 Re in the midnight sector magnetosphere and from ground-based ionospheric sensors during a substorm dipolarization followed by rapid reenergization of multi-MeV electrons [1]. A 50% increase in magnetic field magnitude occurred simultaneously with dramatic increases in 100 keV electron fluxes and a 100 times increase in VLF wave intensity. Chorus is excited following the injection of low-energy (1–30 keV) plasma sheet electrons into the inner magnetosphere [2]. During the 17 March substorm injection, cold plasma that had circulated into the nightside. . .
Date: 08/2014 Publisher: IEEE DOI: 10.1109/URSIGASS.2014.6929876 Available at: http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6929876
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Authors: Foster J. C., Erickson P. J., Baker D N, Jaynes A. N., Mishin E. V., et al.
Title: Observations of the impenetrable barrier, the plasmapause, and the VLF bubble during the 17 March 2015 storm
Abstract: Van Allen Probes observations during the 17 March 2015 major geomagnetic storm strongly suggest that VLF transmitter-induced waves play an important role in sculpting the earthward extent of outer zone MeV electrons. A magnetically confined bubble of very low frequency (VLF) wave emissions of terrestrial, human-produced origin surrounds the Earth. The outer limit of the VLF bubble closely matches the position of an apparent barrier to the inward extent of multi-MeV radiation belt electrons near 2.8 Earth radii. When the VLF transmitter signals extend beyond the eroded plasmapause, electron loss processes set up near the outer extent of the VLF bubble create an earthward limit to the region of local acceleration near L = 2.8 as MeV electrons are scattered into the atmospheric loss cone.
Date: 06/2016 Publisher: Journal of Geophysical Research: Space Physics Pages: 5537 - 5548 DOI: 10.1002/jgra.v121.610.1002/2016JA022509 Available at: http://doi.wiley.com/10.1002/2016JA022509
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Authors: Foster J. C., Wygant J R, Hudson M K, Boyd A. J., Baker D N, et al.
Title: Shock-Induced Prompt Relativistic Electron Acceleration In the Inner Magnetosphere
Abstract: We present twin Van Allen Probes spacecraft observations of the effects of a solar wind shock impacting the magnetosphere on 8 October 2013. The event provides details both of the accelerating electric fields associated with the shock and the response of inner magnetosphere electron populations across a broad range of energies. During this period the two Van Allen Probes observed shock effects from the vantage point of the dayside magnetosphere at radial positions of L=3 and L=5, at the location where shock-induced acceleration of relativistic electrons occurs. The extended (~1 min) duration of the accelerating electric field across a broad extent of the dayside magnetosphere, coupled with energy dependent relativistic electron gradient drift velocities, selects a preferred range of energi. . .
Date: 01/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020642 Available at: http://doi.wiley.com/10.1002/2014JA020642
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Authors: Foster J. C., Erickson P. J., Omura Y., Baker D N, Kletzing C A, et al.
Title: Van Allen Probes Observations of Prompt MeV Radiation Belt Electron Acceleration in Non-Linear Interactions with VLF Chorus
Abstract: Prompt recovery of MeV electron populations in the post-storm core of the outer terrestrial radiation belt involves local acceleration of a seed population of energetic electrons in interactions with VLF chorus waves. Electron interactions during the generation of VLF rising tones are strongly non-linear, such that a fraction of the relativistic electrons at resonant energies are trapped by waves, leading to significant non-adiabatic energy exchange. Through detailed examination of VLF chorus and electron fluxes observed by Van Allen Probes, we investigate the efficiency of non-linear processes for acceleration of electrons to MeV energies. We find through subpacket analysis of chorus waveforms that electrons with initial energy 100s keV - 3 MeV can be accelerated by 50 keV - 200 keV in re. . .
Date: 12/2016 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA023429 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA023429/full
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Authors: Forsyth C., Rae I. J., Murphy K. R., Freeman M. P., Huang C.-L., et al.
Title: What effect do substorms have on the content of the radiation belts?
Abstract: Substorms are fundamental and dynamic processes in the magnetosphere, converting captured solar wind magnetic energy into plasma energy. These substorms have been suggested to be a key driver of energetic electron enhancements in the outer radiation belts. Substorms inject a keV “seed” population into the inner magnetosphere which is subsequently energized through wave-particle interactions up to relativistic energies; however, the extent to which substorms enhance the radiation belts, either directly or indirectly, has never before been quantified. In this study, we examine increases and decreases in the total radiation belt electron content (TRBEC) following substorms and geomagnetically quiet intervals. Our results show that the radiation belts are inherently lossy, shown by a negat. . .
Date: 06/2016 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA022620 Available at: http://doi.wiley.com/10.1002/2016JA022620
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Authors: Fok M.-C., Buzulukova N. Y., Chen S.-H., Glocer A., Nagai T., et al.
Title: The Comprehensive Inner Magnetosphere-Ionosphere Model
Abstract: Simulation studies of the Earth's radiation belts and ring current are very useful in understanding the acceleration, transport, and loss of energetic particles. Recently, the Comprehensive Ring Current Model (CRCM) and the Radiation Belt Environment (RBE) model were merged to form a Comprehensive Inner Magnetosphere-Ionosphere (CIMI) model. CIMI solves for many essential quantities in the inner magnetosphere, including ion and electron distributions in the ring current and radiation belts, plasmaspheric density, Region 2 currents, convection potential, and precipitation in the ionosphere. It incorporates whistler mode chorus and hiss wave diffusion of energetic electrons in energy, pitch angle, and cross terms. CIMI thus represents a comprehensive model that considers the effects of the r. . .
Date: 09/2014 Publisher: Journal of Geophysical Research: Space Physics Pages: 7522 - 7540 DOI: 10.1002/jgra.v119.910.1002/2014JA020239 Available at: http://doi.wiley.com/10.1002/jgra.v119.9http://doi.wiley.com/10.1002/2014JA020239
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Authors: Firpi Alexer H., Oxenrider Jason R., Ramachandran Vignesh R., Mitchell Herbert J., Tzeng Nigel H., et al.
Title: Signature modeling for LWIR spectrometer
Abstract: Hyperspectral longwave infrared (LWIR) is used for a variety of targets such as gases and solids with the advantage of day or night data collections. A longwave infrared system must have the ability to convert the radiance data it measures to emissivity prior to running a detection algorithm, commonly called a temperature-emissivity separation (TES) algorithm. Key parts of this TES algorithm are accounting for the reflected down-welling radiation from the atmosphere, upwelling background radiance removal, and most importantly determining the temperature of the material. Accounting for these environmental conditions allows for the data to be processed in emissivity to be used in the detection algorithm. The processed data also allows a baseline to determine where key features exist in the s. . .
Date: 03/2014 Publisher: IEEE DOI: 10.1109/AERO.2014.6836439 Available at: http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6836439
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Authors: Finnigan Jeremiah
Title: A scripting framework for automated flight SW testing: Van Allen Probes lessons learned
Abstract: This paper summarizes the lessons learned from implementing and utilizing an automated flight software test framework for the Van Allen Probes mission. This includes a recommended list of features/characteristics that a test framework should support. This paper also presents two test scripting design patterns that are useful for constructing an automated regression test suite. These design patterns are intended for non-object-oriented scripting environments - which is typical of space mission ground systems. A process flow is described for developing and utilizing an automated test scripting framework for future missions based upon the design patterns presented herein.
Date: 03/2014 Publisher: IEEE DOI: 10.1109/AERO.2014.6836164 Available at: http://ieeexplore.ieee.org/lpdocs/epic03/wrapper.htm?arnumber=6836164
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Authors: Ferradas C. P., Zhang J.-C., Spence H E, Kistler L. M., Larsen B A, et al.
Title: Drift paths of ions composing multiple-nose spectral structures near the inner edge of the plasma sheet
Abstract: We present a case study of the H+, He+, and O+ multiple-nose structures observed by the Helium, Oxygen, Proton, and Electron instrument on board Van Allen Probe A over one complete orbit on 28 September 2013. Nose structures are observed near the inner edge of the plasma sheet and constitute the signatures of ion drift in the highly dynamic environment of the inner magnetosphere. We find that the multiple noses are intrinsically associated with variations in the solar wind. Backward ion drift path tracings show new details of the drift trajectories of these ions; i.e., multiple noses are formed by ions with a short drift time from the assumed source location to the inner region and whose trajectories (1) encircle the Earth different number of times or (2) encircle the Earth equal number of. . .
Date: 11/2016 Publisher: Geophysical Research Letters DOI: 10.1002/2016GL071359 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016GL071359/full
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Authors: Ferradas C. P., Zhang J.-C., Kistler L. M., and Spence H E
Title: Heavy-ion dominance near Cluster perigees
Abstract: Time periods in which heavy ions dominate over H+ in the energy range of 1-40 keV were observed by the Cluster Ion Spectrometry (CIS)/COmposition DIstribution Function (CODIF) instrument onboard Cluster Spacecraft 4 at L-values less than 4. The characteristic feature is a narrow flux peak at around 10 keV that extends into low L-values, with He+ and/or O+ dominating. In the present work we perform a statistical study of these events and examine their temporal occurrence and spatial distribution. The observed features, both the narrow energy range and the heavy-ion dominance, can be interpreted using a model of ion drift from the plasma sheet, subject to charge exchange losses. The narrow energy range corresponds to the only energy range that has direct drift access from the plasma sheet du. . .
Date: 10/2015 Publisher: Journal of Geophysical Research: Space Physics Pages: n/a - n/a DOI: 10.1002/2015JA021063 Available at: http://doi.wiley.com/10.1002/2015JA021063http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2F2015JA021063
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Authors: Ferradas C. P., Zhang J.-C., Spence H E, Kistler L. M., Larsen B A, et al.
Title: Ion nose spectral structures observed by the Van Allen Probes
Abstract: We present a statistical study of nose-like structures observed in energetic hydrogen, helium, and oxygen ions near the inner edge of the plasma sheet. Nose structures are spectral features named after the characteristic shapes of energy bands or gaps in the energy-time spectrograms of in situ measured ion fluxes. Using 22 months of observations from the Helium Oxygen Proton Electron (HOPE) instrument onboard Van Allen Probe A, we determine the number of noses observed, and the minimum L-shell reached and energy of each nose on each pass through the inner magnetosphere. We find that multiple noses occur more frequently in heavy ions than in H+, and are most often observed during quiet times. The heavy-ion noses penetrate to lower L shells than H+ noses and there is an energy-magnetic loc. . .
Date: 11/2016 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA022942 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA022942/full
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Authors: Ferradas C. P., Zhang J.-C., Spence H E, Kistler L. M., Larsen B A, et al.
Title: Temporal evolution of ion spectral structures during a geomagnetic storm: Observations and modeling
Abstract: Using the Van Allen Probes/Helium, Oxygen, Proton, and Electron (HOPE) mass spectrometer, we perform a case study of the temporal evolution of ion spectral structures observed in the energy range of 1-~50 keV throughout the geomagnetic storm of 2 October 2013. The ion spectral features are observed near the inner edge of the plasma sheet and are signatures of fresh transport from the plasma sheet into the inner magnetosphere. We find that the characteristics of the ion structures are determined by the intensity of the convection electric field. Prior to the beginning of the storm, the plasma sheet inner edge exhibits narrow nose spectral structures that vary little in energy across L values. Ion access to the inner magnetosphere during these times is limited to the nose energy bands. As co. . .
Date: 12/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024702 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024702/full
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Authors: Fernandes Philip A., Larsen Brian A., Thomsen Michelle F., Skoug Ruth M., Reeves Geoffrey D, et al.
Title: The plasma environment inside geostationary orbit: A Van Allen Probes HOPE survey
Abstract: The two full precessions in local time completed by the Van Allen Probes enable global specification of the near-equatorial inner magnetosphere plasma environment. Observations by the Helium-Oxygen-Proton-Electron (HOPE) mass spectrometers provide detailed insight into the global spatial distribution of electrons, H+, He+, and O+. Near-equatorial omnidirectional fluxes and abundance ratios at energies 0.1–30 keV are presented for 2 ≤ L ≤ 6 as a function of L shell, magnetic local time (MLT), and geomagnetic activity. We present a new tool built on the UBK modeling technique for classifying plasma sheet particle access to the inner magnetosphere. This new tool generates access maps for particles of constant energy for more direct comparison with in situ measurements, rather than the t. . .
Date: 08/2017 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024160 Available at: onlinelibrary.wiley.com/doi/10.1002/2017JA024160/full
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Authors: Fennell J. F., Roeder J. L., Kurth W S, Henderson M G, Larsen B A, et al.
Title: Van Allen Probes observations of direct wave-particle interactions
Abstract: Quasiperiodic increases, or “bursts,” of 17–26 keV electron fluxes in conjunction with chorus wave bursts were observed following a plasma injection on 13 January 2013. The pitch angle distributions changed during the burst events, evolving from sinN(α) to distributions that formed maxima at α = 75–80°, while fluxes at 90° and <60° remained nearly unchanged. The observations occurred outside of the plasmasphere in the postmidnight region and were observed by both Van Allen Probes. Density, cyclotron frequency, and pitch angle of the peak flux were used to estimate resonant electron energy. The result of ~15–35 keV is consistent with the energies of the electrons showing the flux enhancements and corresponds to electrons in and above the steep flux gradient that signa. . .
Date: 03/2014 Publisher: Geophysical Research Letters Pages: 1869 - 1875 DOI: 10.1002/2013GL059165 Available at: http://doi.wiley.com/10.1002/2013GL059165
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Authors: Fennell J. F., Blake J B, Claudepierre S., Mazur J, Kanekal S., et al.
Title: Current energetic particle sensors
Abstract: Several energetic particle sensors designed to make measurements in the current decade are described and their technology and capabilities discussed and demonstrated. Most of these instruments are already on orbit or approaching launch. These include the Magnetic Electron Ion Spectrometers (MagEIS) and the Relativistic Electron Proton Telescope (REPT) that are flying on the Van Allen Probes, the Fly's Eye Electron Proton Spectrometers (FEEPS) flying on the Magnetospheric Multiscale (MMS) mission, and Dosimeters flying on the AC6 Cubesat mission. We focus mostly on the electron measurement capability of these sensors while providing summary comments of their ion measurement capabilities if they have any.
Date: 09/2016 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2016JA022588 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2016JA022588/abstract
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Authors: Fennell J. F., Claudepierre S G, Blake J B, O'Brien T P, Clemmons J. H., et al.
Title: Van Allen Probes show the inner radiation zone contains no MeV electrons: ECT/MagEIS data
Abstract: We present Van Allen Probe observations of electrons in the inner radiation zone. The measurements were made by the ECT/MagEIS sensors that were designed to measure electrons with the ability to remove unwanted signals from penetrating protons, providing clean measurements. No electrons >900 keV were observed with equatorial fluxes above background (i.e. >0.1 electrons/(cm2 s sr keV)) in the inner zone. The observed fluxes are compared to the AE9 model and CRRES observations. Electron fluxes <200 keV exceeded the AE9 model 50% fluxes and were lower than the higher energy model fluxes. Phase space density radial profiles for 1.3≤L*<2.5 had mostly positive gradients except near L*~2.1 where the profiles for μ = 20-30 MeV/G were flat or slightly peaked. The major result is that MagEIS data. . .
Date: 02/2015 Publisher: Geophysical Research Letters DOI: 10.1002/2014GL062874 Available at: http://doi.wiley.com/10.1002/2014GL062874
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Authors: Fei Yue, Chan Anthony A, Elkington Scot R, and Wiltberger Michael J
Title: Radial diffusion and MHD particle simulations of relativistic electron transport by ULF waves in the September 1998 storm
Abstract: In an MHD particle simulation of the September 1998 magnetic storm the evolution of the radiation belt electron radial flux profile appears to be diffusive, and diffusion caused by ULF waves has been invoked as the probable mechanism. In order to separate adiabatic and nonadiabatic effects and to investigate the radial diffusion mechanism during this storm, in this work we solve a radial diffusion equation with ULF wave diffusion coefficients and a time-dependent outer boundary condition, and the results are compared with the phase space density of the MHD particle simulation. The diffusion coefficients include contributions from both symmetric resonance modes (ω ≈ mωd, where ω is the wave frequency, m is the azimuthal wave number, and ωd is the bounce-averaged drift frequency) and . . .
Date: 12/2006 Publisher: Journal of Geophysical Research DOI: 10.1029/2005JA011211 Available at: http://onlinelibrary.wiley.com/doi/10.1029/2005JA011211/abstract
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Authors: Fathy A., Kim K.-H., Park J.-S., Jin H., Kletzing C., et al.
Title: Characteristics of Sudden Commencements Observed by Van Allen Probes in the Inner Magnetosphere
Abstract: We have statistically studied sudden commencement (SC) by using the data acquired from Van Allen Probes (VAP) in the inner magnetosphere (L = 3.0–6.5) and GOES spacecraft at geosynchronous orbit (L =∼ 6.7) from October 2012 to September 2017. During the time period, we identified 85 SCs in the inner magnetosphere and 90 SCs at geosynchronous orbit. Statistical results of the SC events reveal the following characteristics. (1) There is strong seasonal dependence of the geosynchronous SC amplitude in the radial BV component at all local times. However, BV shows weak seasonal variation on the dayside in the inner magnetosphere. (2) The local time dependence of the SC amplitude in the compressional BH component at geosynchronous orbit is similar to that in the inner magnetosphere. (3) In a. . .
Date: 02/2018 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2017JA024770 Available at: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024770/full
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Authors: Farley Thomas A
Title: Radial Diffusion of Starfish Electrons
Abstract: A study of the change in electron intensities in the Starfish electron belt from January 1, 1963, to November 3, 1965, indicates that radial diffusion, both inward and outward from L of 1.40, was a significant loss mechanism for these electrons during this period. For L values of 1.20 and below, the indicated steepening of the pitch-angle distributions during this period has been interpreted as the result of a radial diffusion source for each L shell concentrated near the geomagnetic equator. Since pitch-angle diffusion lifetimes are not well known for 1.20 < L < 1.65, a definitive radial diffusion coefficient cannot be computed from these data. A maximum reasonable diffusion coefficient (mean square displacement per unit time) computed for this range of L for this period has a minimum at . . .
Date: 07/1969 Publisher: Journal of Geophysical Research Pages: 3591 - 3600 DOI: 10.1029/JA074i014p03591 Available at: http://onlinelibrary.wiley.com/doi/10.1029/JA074i014p03591/abstract
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Authors: Falthammar C -G
Title: Effects of time-dependent electric fields on geomagnetically trapped radiation.
Abstract: Large-scale electric potential fields in the magnetosphere are generally invoked in theories of the aurora. It is shown in the present article that irregular fluctuations of such fields cause a random radial motion of trapped energetic particles by violating the third adiabatic invariant. When the first and second invariants are conserved, any radial motion of the particles is associated with a corresponding energy change. Some particles move outward and others inward; but, if there is a source in the outer magnetosphere and a sink farther in, there will be a net inward transport and an associated net energy gain. This mechanism supplements that of particle transport by magnetic disturbances, which has already been discussed in the literature. The transport and acceleration of energetic pa. . .
Date: 06/1965 Publisher: Journal of Geophysical Research Pages: 2503–2516 DOI: 10.1029/JZ070i011p02503 Available at: http://onlinelibrary.wiley.com/doi/10.1029/JZ070i011p02503/full
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