Sub-Auroral Polarization Stream (SAPS) duration as determined from Van Allen Probe successive electric drift measurements

TitleSub-Auroral Polarization Stream (SAPS) duration as determined from Van Allen Probe successive electric drift measurements
Publication TypeJournal Article
Year of Publication2017
AuthorsLejosne, ène, Mozer, FS
JournalGeophysical Research Letters
Date Published08/2017
Keywordsduration; electric drift measurements; magnetosphere-ionosphere coupling; SAPS; Van Allen Probes
AbstractWe examine a characteristic feature of the magnetosphere-ionosphere coupling, namely, the persistent and latitudinally narrow bands of rapid westward ion drifts called the Sub-Auroral Polarization Streams (SAPS). Despite countless works on SAPS, information relative to their durations is lacking. Here, we report on the first statistical analysis of more than 200 near-equatorial SAPS observations based on more than two years of Van Allen Probe electric drift measurements. First, we present results relative to SAPS radial locations and amplitudes. Then, we introduce two different ways to estimate SAPS durations. In both cases, SAPS activity is estimated to last for about nine hours on average. However, our estimates for SAPS duration are limited either by the relatively long orbital periods of the spacecraft or by the relatively small number of observations involved. 50 % of the events fit within the time interval [0;18] hours.
URLhttp://http://onlinelibrary.wiley.com/doi/10.1002/2017GL074985/full
DOI10.1002/2017GL074985
Short TitleGeophys. Res. Lett.


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