Articles | Volume 34, issue 5
Regular paper
10 May 2016
Regular paper |  | 10 May 2016

The dawn–dusk asymmetry of ion density in the dayside magnetosheath and its annual variability measured by THEMIS

Andrew P. Dimmock, Tuija I. Pulkkinen, Adnane Osmane, and Katariina Nykyri

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Ion densities measured on the dawn-side magnetosheath flank were higher than the dusk-flank. The asymmetry was measured close to the magnetopause, but it became more ambiguous in the central magnetosheath. We show that the asymmetry was at its maximum at the 2009 solar minimum (~ 20 %), but then decreased in the rising stage of the next solar cycle (< 5 %). These results could impact plasma transport processes which are dependent on local magnetopause conditions such as Kelvin Helmholtz Instability.