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Article
A Statistical Study Into the Spatial Distribution and Dawn-Dusk Asymmetry of Dayside Magnetosheath Ion Temperatures as a Function of Upstream Solar Wind Conditions
Journal of Geophysical Research: Space Physics
  • A. P. Dimmock, Aalto University
  • K. Nykyri, Embry-Riddle Aeronautical University
  • H. Karimabadi, University of California - San Diego
  • A. Osmane, Aalto University
  • T. I. Pulkkinen, Aalto University
Submitting Campus
Daytona Beach
Department
Physical Sciences
Document Type
Article
Publication/Presentation Date
4-1-2015
Abstract/Description

The magnetosheath contains the shocked solar wind and behaves as a natural filter to the solar wind plasma before it reaches the magnetosphere. The redistribution of kinetic energy at the bow shock results in significant thermalization of the solar wind plasma, resulting in a magnetosheath temperature profile which is highly nonhomogeneous and nonisotropic and differs between the dawn and dusk flanks. The present study attempts to study the spatial distribution of magnetosheath ion temperature as a function of upstream solar wind conditions. We pay particular attention to the dawn/dusk asymmetry in which we attempt to quantify using experimental data collected over a 7 year period. We also compare these data to simulated data from both the Block-Adaptive-Tree-Solarwind-Roe-Upwind-Scheme (BATS-R-US) MHD code and a kinetic hybrid model. We present evidence that the dawn flank is consistently hotter than the dusk flank for a variety of upstream conditions. Our statistical data also suggest a dependency on solar wind speed such that the level of asymmetry increases with faster speeds. We conclude that the dawn-favored asymmetry of the magnetosheath seed population is insufficient to explain the dawn asymmetry (30–40%) of cold component ions in the cold, dense plasma sheet, and therefore, other mechanisms are likely required.

DOI
https://doi.org/10.1002/2014JA029734
Publisher
American Geophysical Union
Grant or Award Name
NSF grant 0847120 and Academy of Finland grant 267073/2013
Citation Information
Dimmock, A. P., K. Nykyri, H. Karimabadi, A. Osmane, and T. I. Pulkkinen (2015), A statistical study into the spatial distribution and dawn-dusk asymmetry of dayside magnetosheath ion temperatures as a function of upstream solar wind conditions, J. Geophys. Res. Atmos., 120, 2767–2782, doi:10.1002/2014JA020734