Analysis of SAPS using the Millstone Hill incoherent scatter radar data
Abstract
A statistical study of the subauroral polarization stream (SAPS) over the North American sector is conducted by using the Millstone Hill incoherent scatter radar measurements from 1979 to 2019. The key features of SAPS and its associated plasma parameters, such as ion vertical flow, electron density, ion temperature, and electron temperature, are analyzed via a superposed epoch analysis method. The characteristics of these parameters are investigated with respect to magnetic local time, season, geomagnetic activity, solar activity, and interplanetary magnetic field (IMF) orientation, respectively. The main results are as follows: (1) There is obvious ion upward flow around SAPS peak region. Both of them exhibit similar variation patterns with a larger magnitude around dusk than midnight, in winter than summer, during active geomagnetic periods than quiet time, in solar minimum than maximum, and under IMF conditions with negative By and negative Bz. (2) SAPS is usually associated with a midlatitude trough of 15--20% depletion. The trough has specific local time and seasonal preference, which is more pronounced in postmidnight and around equinoxes. (3) The subauroral ion and electron temperature exhibit 3--8% enhancement associated with SAPS. Both of them have more considerable enhancement during geomagnetically active periods, and during midnight than dusk. Condition for ion temperature enhancement is more favored during low solar activity periods, while the electron temperature enhancement is almost constant within the solar cycle.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMSA024..06A
- Keywords:
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- 2427 Ionosphere/atmosphere interactions;
- IONOSPHERE;
- 2431 Ionosphere/magnetosphere interactions;
- IONOSPHERE;
- 2704 Auroral phenomena;
- MAGNETOSPHERIC PHYSICS;
- 2736 Magnetosphere/ionosphere interactions;
- MAGNETOSPHERIC PHYSICS