Testing the Efficacy of Selected Scalar Parameters for Identifying Ion Diffusion Regions in MMS Data
Abstract
Canonical parameters for Ion Diffusion Region (IDR) identification such as ion flow reversals or Hall fields rely on the observatory passing through several spatially-separated features in the region surrounding the reconnecting X-line and on the accurate determination of a coordinate system natural to the X-line. Scalar parameters derived from direct field measurements and particle distribution functions do not rely on any particular coordinate system or flight path of the observatory. Examples such as particle agyrotropy and the adiabatic expansion parameter have been suggested to identify or even define the Electron Diffusion Region (EDR) when applied to electron measurements. The same physics is equally applicable to ion diffusion and demagnetization. We present four such parameters, adapted for use with ion measurements, and test their efficacy in identifying IDRs in the geomagnetic tail during the 2017-2019 MMS tail seasons. We compare them in regions containing known IDRs identified independently using canonical criteria against regions where no IDRs exist. While no parameter is found to be sufficient for IDR identification, a combination of scalar parameters prove to be moderately effective.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMSM21B3155R
- Keywords:
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- 2723 Magnetic reconnection;
- MAGNETOSPHERIC PHYSICS;
- 2744 Magnetotail;
- MAGNETOSPHERIC PHYSICS;
- 7526 Magnetic reconnection;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY;
- 7835 Magnetic reconnection;
- SPACE PLASMA PHYSICS