Solar wind drivers in the magnetosheath: Long-term evolution
Abstract
We study the long-term variability of the solar wind - magnetosphere - ionosphere coupling using several coupling functions to describe the solar wind input. As all plasma entering the magnetosphere is processed through the bow shock, magnetosheath, and the magnetopause, the complex dynamics of the solar wind - magnetosphere coupling is affected by the properties of the boundaries at the shock and the magnetopause as well as the dynamics within the magnetosheath. Data from the THEMIS 5-spacecraft mission processed in the magnetosphere - interplanetary medium reference frame are used to study the magnetosheath properties. We demonstrate that the magnetosheath dynamics exhibits long-term variability associated with solar cycle evolution, and show how it varies as function of solar wind parameters. Especially, we focus on the energy entering the magnetosphere through the magnetopause in the form of Poynting flux. The IMAGE magnetometer chain measurements are used to trace the corresponding effects in the ionosphere over the THEMIS period, and also in a longer-term solar cycle perspective. The GUMICS-4 global MHD simulation quantitative results of energy entry and of the coupling of the boundary processes to the polar cap are used to provide a context and reference for the statistical observations.
- Publication:
-
42nd COSPAR Scientific Assembly
- Pub Date:
- July 2018
- Bibcode:
- 2018cosp...42E2744P