MHD and kinetic analysis of flow bursts in the Earth's plasma sheet
Abstract
In an attempt to study the flow bursts in the Earth's plasma sheet we select an event that took place on 7 August 2004 in the expansion phase of a substorm, using data from the geomagnetic index, solar wind data, plasma and magnetic field observations from C1 Cluster satellite (the Cluster mission has 4 satellites) and from Double Star TC-1 satellite. In MHD approach, TC-1 firstly observed the tailward flow, then the earthward, and finally the flow was alternating in two directions. C1 firstly observed the earthward plasma flow, and then the tailward. Before flow bursts are observed by TC-1 and C1, there are disturbances in local entropy with tailward local entropy larger than that of the earthward. The kinetic features of the plasma flow observed by C1 are similar to that in MHD. However, kinetic characteristics of the plasma flow observed by TC-1 are far more than the description in MHD. The inadequacy mainly exist in two cases: (1) the firstly enhanced tailward flows given in MHD are found without significant increase of the energetic tailward flux (2) The almost stagnant flow in MHD are composed of enhanced energetic ion flux both in earthward and tailward direction. The earthward flow burst observed by TC-1 might be multiple overshoots and rebounds. The earthward flow burst observed by C1 might be simply rebounded in the near-Earth. The pulsation observed by C1 is earlier than that observed by TC-1 with the former intensity less than that of the latter. After the energetic ion flux in the tailward direction is significantly enhanced, the power spectrum intensity of the ULF wave commences to increase obviously, which may support that the stream instability are closely correlated with ULF pulsations.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFMSM11B2079M
- Keywords:
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- 2740 MAGNETOSPHERIC PHYSICS Magnetospheric configuration and dynamics