| Autor: |
L. Q. Zhang, Chi Wang, L. Dai, W. Baumjohann, James L. Burch, Yu. V. Khotyaintsev, J. Y. Wang |
| Jazyk: |
angličtina |
| Rok vydání: |
2022 |
| Předmět: |
|
| Zdroj: |
Scientific Reports, Vol 12, Iss 1, Pp 1-8 (2022) |
| Druh dokumentu: |
article |
| ISSN: |
2045-2322 |
| DOI: |
10.1038/s41598-022-19266-6 |
| Popis: |
Abstract Utilizing four-point joint observations by Magnetospheric Multiscale Spacecraft (MMS), we investigate the main features of the current sheet frozen in (CSFI) the bursty bulk flow. Typical event on the steady long-lasting BBF on July 23, 2017 shows the enhanced dawn-dusk current (Jy0) in the CSFI (β ~ 10). The magnitude of the Jy0 in the CSFI is about 5.5 nA/m2. The CSFI is highly turbulent, with the ratio of ∆J/J0 of ~ 2 (where ∆J is perturbed J). The turbulent CSFI is characterized by intermittent current coherent structures. The magnitude of the spiky-J at coherent structures is typically above 30 nA/m2. Spectrum analysis exhibits that BBF turbulence follows distinct dissipation laws inside and outside the CSFI. Based on MMS observations, we propose a new model of the BBF in the framework of magnetohydrodynamics. In this model, the BBF is depicted as a closed plasma system with the localized current sheet frozen at the center of the flow (Taylor’s hypothesis). In the light of principle of Helmholtz-decomposition, the BBF motion in the tail plasma sheet is explained. The model also predicts the thermal expansion of the BBF after leaving the reconnection source region. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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