MMS Observations of the Kinetic Processes within an Interplanetary Shock
Abstract
Shock waves in collisionless plasmas are fundamental instigators of particle thermalization and acceleration by partitioning, in unknown proportions, the dominant influx of bulk flow energy as part of an overall super-to sub-sonic transition. Many of the kinetic processes responsible for this partition have been explored by in situ spacecraft primarily at Earth's standing bow shock as well as more limited studies at other planetary bow shocks. Such bow shocks are typically high in Mach number, in the "super-critical" regime. We have exploited the unprecedented resolution of data from the MMS mission to reveal the kinetic structure of a weaker, travelling interplanetary shock. Although this particular shock is slightly above the critical Mach number, it provides a testbed for MMS capability. We report resolved observations of specularly-reflected solar wind protons within the shock layer. We also use MMS's 4-spacecraft strategy to calculate the electron pressure gradient and other contributions to the cross-shock electric field, comparing them directly with MMS full 3D electric field measurements. Finally, we show that the quasi-DC electric fields are actually provided by much larger amplitude higher frequency structures, such as double layers. These structures also appear periodically downstream of the shock where they help complete the relaxation of the shocked plasma.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMSH33A..01S
- Keywords:
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- 2772 Plasma waves and instabilities;
- MAGNETOSPHERIC PHYSICSDE: 7845 Particle acceleration;
- SPACE PLASMA PHYSICSDE: 7846 Plasma energization;
- SPACE PLASMA PHYSICSDE: 7851 Shock waves;
- SPACE PLASMA PHYSICS