Biblio

Found 4 results
Filters: Keyword is ion injection  [Clear All Filters]
2017
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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2016
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., 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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2015
Authors: Zhang J.-C., Kistler L. M., Spence H E, Wolf R. A., Reeves G., et al.
Title: “Trunk-like” heavy ion structures observed by the Van Allen Probes
Abstract: Dynamic ion spectral features in the inner magnetosphere are the observational signatures of ion acceleration, transport, and loss in the global magnetosphere. We report “trunk-like” ion structures observed by the Van Allen Probes on 2 November 2012. This new type of ion structure looks like an elephant's trunk on an energy-time spectrogram, with the energy of the peak flux decreasing Earthward. The trunks are present in He+ and O+ ions but not in H+. During the event, ion energies in the He+ trunk, located at L = 3.6–2.6, MLT = 9.1–10.5, and MLAT = −2.4–0.09°, vary monotonically from 3.5 to 0.04 keV. The values at the two end points of the O+ trunk are: energy = 4.5–0.7 keV, L = 3.6–2.5, MLT = 9.1–10.7, and MLAT = −2.4–0.4°. Results from backward ion drift path tra. . .
Date: 10/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2015JA021822 Available at: http://doi.wiley.com/10.1002/2015JA021822http://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2F2015JA021822
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