The ion/electron temperature characteristics of polar cap classical and hot patches and their influence on ion upflow
Abstract
The term of "polar cap hot patch" is a newly identified high-density plasma irregularity at high latitudes, which is associated with high electron temperature and particle precipitation, while a classical polar cap patch has lower electron temperature. To investigate characteristics of hot patches vs. classical patches, 5-years of in-situ database of plasma observations from the DMSP satellites was analyzed. For the first time, we show how the ion/electron temperature ratio (or temperature difference) can be used to distinguish between classical and hot patches. For classical patches (Ti/Te > 0.8, or Te < Ti + 600 K) the vertical ion flux is generally downward. For hot patches (Ti/Te < 0.8, or Te > Ti + 600 K) the vertical ion flux is generally upward. The highest upflow occurrence was found near the polar cap boundary, associated with hot patches, particle precipitation, strong convection speed, localized field-aligned currents. This result shows that the polar cap hot patches may play a very important role in solar wind-magnetosphere-ionosphere coupling processes.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMSA41B3488Y
- Keywords:
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- 2431 Ionosphere/magnetosphere interactions;
- IONOSPHEREDE: 2437 Ionospheric dynamics;
- IONOSPHEREDE: 2704 Auroral phenomena;
- MAGNETOSPHERIC PHYSICSDE: 2788 Magnetic storms and substorms;
- MAGNETOSPHERIC PHYSICS