Bibliography



Notice:

  • Clicking on the title will open a new window with all details of the bibliographic entry.
  • Clicking on the DOI link will open a new window with the original bibliographic entry from the publisher.
  • Clicking on a single author will show all publications by the selected author.
  • Clicking on a single keyword, will show all publications by the selected keyword.



Found 1 entries in the Bibliography.


Showing entries from 1 through 1


2016

Van Allen Probes observations of magnetic field dipolarization and its associated O + flux variations in the inner magnetosphere at L < 6.6

We investigate magnetic field dipolarization in the inner magnetosphere and its associated ion flux variations, using the magnetic field and energetic ion flux data acquired by the Van Allen Probes. From a study of 74 events that appeared at L = 4.5\textendash6.6 between 1 October 2012 and 31 October 2013, we reveal the following characteristics of the dipolarization in the inner magnetosphere: (1) its timescale is approximately 5 min, (2) it is accompanied by strong magnetic fluctuations that have a dominant frequency close to the O+ gyrofrequency, (3) ion fluxes at 20\textendash50 keV are simultaneously enhanced with larger magnitudes for O+ than for H+, (4) after a few minutes of the dipolarization, the flux enhancement at 0.1\textendash5 keV appears with a clear energy-dispersion signature only for O+, and (5) the energy-dispersed O+ flux enhancement appears in directions parallel or anti-parallel to the magnetic field. From these characteristics, we discuss possible mechanisms that can provide selective acceleration to O+ ions at >20 keV. We conclude that O+ ions at L = 5.4\textendash6.6 undergo nonadiabatic local acceleration caused by oscillating electric field associated with the magnetic fluctuations and/or adiabatic convective transport from the plasma sheet to the inner magnetosphere by the impulsive electric field. At L = 4.5\textendash5.4, however, only the former acceleration is plausible. We also conclude that the field-aligned energy-dispersed O+ ions at 0.1\textendash5 keV originate from the ionosphere and are extracted nearly simultaneously to the onset of the dipolarization.

e, M.; Keika, K.; Kletzing, C.; Spence, H.; Smith, C.; MacDowall, R.; Reeves, G.; Larsen, B.; Mitchell, D.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 07/2016

YEAR: 2016     DOI: 10.1002/2016JA022549

Dipolarization; inner magnetosphere; ionospheric outflow; Magnetic Fluctuation; O+ Acceleration; substorm; Van Allen Probes



  1