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Found 4 entries in the Bibliography.
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2020 |
A New Approach to Constructing Models of Electron Diffusion by EMIC Waves in the Radiation Belts Electromagnetic ion cyclotron (EMIC) waves play an important role in relativistic electron losses in the radiation belts through diffusion via resonant wave-particle interactions. We present a new approach for calculating bounce and drift-averaged EMIC electron diffusion coefficients. We calculate bounce-averaged diffusion coefficients, using quasi-linear theory, for each individual Combined Release and Radiation Effects Satellite (CRRES) EMIC wave observation using fitted wave properties, the plasma density and the background magnetic field. These calculations are then combined into bounce-averaged diffusion coefficients. The resulting coefficients therefore capture the combined effects of individual spectra and plasma properties as opposed to previous approaches that use average spectral and plasma properties, resulting in diffusion over a wider range of energies and pitch angles. These calculations, and their role in radiation belt simulations, are then compared against existing diffusion models. The new diffusion coefficients are found to significantly improve the agreement between the calculated decay of relativistic electrons and Van Allen Probes data. Ross, J.; Glauert, S.; Horne, R.; Watt, C.; Meredith, N.; Woodfield, E.; Published by: Geophysical Research Letters Published on: 10/2020 YEAR: 2020   DOI: https://doi.org/10.1029/2020GL088976 Radiation belts; EMIC waves; electron diffusion; Van Allen Probes |
2016 |
With the energetic particle telescope (EPT) performing with direct electron and proton discrimination on board the ESA satellite PROBA-V, we analyze the high-resolution measurements of the charged particle radiation environment at an altitude of 820 km for the year 2015. On 17 March 2015, a big geomagnetic storm event injected unusual fluxes up to low radial distances in the radiation belts. EPT electron measurements show a deep dropout at L > 4 starting during the main phase of the storm, associated to the penetration of high energy fluxes at L < 2 completely filling the slot region. After 10 days, the formation of a new slot around L = 2.8 for electrons of 500\textendash600 keV separates the outer belt from the belt extending at other longitudes than the South Atlantic Anomaly. Two other major events appeared in January and June 2015, again with injections of electrons in the inner belt, contrary to what was observed in 2013 and 2014. These observations open many perspectives to better understand the source and loss mechanisms, and particularly concerning the formation of three belts. Published by: Annales Geophysicae Published on: 01/2016 YEAR: 2016   DOI: 10.5194/angeo-34-75-2016 |
2014 |
The Energetic Particle Detector (EPD) Investigation is one of 5 fields-and-particles investigations on the Magnetospheric Multiscale (MMS) mission. MMS comprises 4 spacecraft flying in close formation in highly elliptical, near-Earth-equatorial orbits targeting understanding of the fundamental physics of the important physical process called magnetic reconnection using Earth\textquoterights magnetosphere as a plasma laboratory. EPD comprises two sensor types, the Energetic Ion Spectrometer (EIS) with one instrument on each of the 4 spacecraft, and the Fly\textquoterights Eye Energetic Particle Spectrometer (FEEPS) with 2 instruments on each of the 4 spacecraft. EIS measures energetic ion energy, angle and elemental compositional distributions from a required low energy limit of 20 keV for protons and 45 keV for oxygen ions, up to >0.5 MeV (with capabilities to measure up to >1 MeV). FEEPS measures instantaneous all sky images of energetic electrons from 25 keV to >0.5 MeV, and also measures total ion energy distributions from 45 keV to >0.5 MeV to be used in conjunction with EIS to measure all sky ion distributions. In this report we describe the EPD investigation and the details of the EIS sensor. Specifically we describe EPD-level science objectives, the science and measurement requirements, and the challenges that the EPD team had in meeting these requirements. Here we also describe the design and operation of the EIS instruments, their calibrated performances, and the EIS in-flight and ground operations. Blake et al. (The Flys Eye Energetic Particle Spectrometer (FEEPS) contribution to the Energetic Particle Detector (EPD) investigation of the Magnetospheric Magnetoscale (MMS) Mission, this issue) describe the design and operation of the FEEPS instruments, their calibrated performances, and the FEEPS in-flight and ground operations. The MMS spacecraft will launch in early 2015, and over its 2-year mission will provide comprehensive measurements of magnetic reconnection at Earth\textquoterights magnetopause during the 18 months that comprise orbital phase 1, and magnetic reconnection within Earth\textquoterights magnetotail during the about 6 months that comprise orbital phase 2. Mauk, B.; Blake, J.; Baker, D.; Clemmons, J.; Reeves, G.; Spence, H.; Jaskulek, S.; Schlemm, C.; Brown, L.; Cooper, S.; Craft, J.; Fennell, J.; Gurnee, R.; Hammock, C.; Hayes, J.; Hill, P.; Ho, G.; Hutcheson, J.; Jacques, A.; Kerem, S.; Mitchell, D.; Nelson, K.; Paschalidis, N.; Rossano, E.; Stokes, M.; Westlake, J.; Published by: Space Science Reviews Published on: 06/2014 YEAR: 2014   DOI: 10.1007/s11214-014-0055-5 Magnetic reconnection; Magnetosphere; Magnetospheric multiscale; NASA mission; Particle acceleration; Space plasma |
2013 |
Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) The Radiation Belt Storm Probes Ion Composition Experiment (RBSPICE) on the two Van Allen Probes spacecraft is the magnetosphere ring current instrument that will provide data for answering the three over-arching questions for the Van Allen Probes Program: RBSPICE will determine \textquotedbllefthow space weather creates the storm-time ring current around Earth, how that ring current supplies and supports the creation of the radiation belt populations,\textquotedblright and how the ring current is involved in radiation belt losses. RBSPICE is a time-of-flight versus total energy instrument that measures ions over the energy range from \~20 keV to \~1 MeV. RBSPICE will also measure electrons over the energy range \~25 keV to \~1 MeV in order to provide instrument background information in the radiation belts. A description of the instrument and its data products are provided in this chapter. Mitchell, D.; Lanzerotti, L.; Kim, C.; Stokes, M.; Ho, G.; Cooper, S.; UKHORSKIY, A; Manweiler, J.; Jaskulek, S.; Haggerty, D.; Brandt, P.; SITNOV, M; Keika, K.; Hayes, J.; Brown, L.; Gurnee, R.; Hutcheson, J.; Nelson, K.; Paschalidis, N.; Rossano, E.; Kerem, S.; Published by: Space Science Reviews Published on: 11/2013 YEAR: 2013   DOI: 10.1007/s11214-013-9965-x |
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