BBF Deceleration Down-Tail of X <-15 RE From MMS Observation

Zhang, L. Q.Chinese Acad Sci, Natl Space Sci Ctr, State Key Lab Space Weather, Beijing, Peoples R China. (författare)

We report the direct observation on bursty bulk flow (BBF) deceleration down-tail of X < -15 R-E by MMS satellite. Two typical events are presented in the paper. In the first event on 05 June 2018, MMS1 is located at X similar to -16.1 R-E and records four individual bursty flows (BFs). Each burst flow has distinctly lower velocity than the preceding one. Accompanying with the decelerated BFs, the Bz/Bx continuously increases/decreases. Simultaneous Vx-decrease and Bz-increase are in coincidence with the scenario of the local BBF deceleration and formation of the magnetic pileup region. In the second event on 03 July 2017, MMS stays in the neutral sheet of X similar to -24.5 R-E, and encounters similar BBF deceleration process. For both events, the decelerated BF series exhibit prominent medium-energy ion component (2-10 KeV). Analyses show enhanced parallel current (J(//)) and Kinetic Alfvenic wave (KAW) emitting during the BF intervals. The strength of the emitted KAW has a clear tendency to decay with the BBF decreasing. Power spectra density analysis confirms the substantial Joule dissipation during the BBF deceleration, both J(//) and J(perpendicular to). Combined analyses support BBF dissipation via Joule heating as well as KAW emitting. Finally, we propose a possible mechanism on the BBF deceleration, i.e., "collision" with the tailward flow.

Baumjohann, W.Austrian Acad Sci, Space Res Inst, Graz, Austria. (författare)
Khotyaintsev, Yuri V.Uppsala universitet,Institutet för rymdfysik, Uppsalaavdelningen(Swepub:uu)ykh28990 (författare)
Burch, James L.Southwest Res Inst San Antonio, San Antonio, TX USA. (författare)
Webster, J.Rice Univ, Houston, TX USA. (författare)
Wang, J. Y.Cent Univ Nationalities, Informat Engn Coll, Beijing, Peoples R China. (författare)
Wang, C.Chinese Acad Sci, Natl Space Sci Ctr, State Key Lab Space Weather, Beijing, Peoples R China. (författare)
Dai, L.Chinese Acad Sci, Natl Space Sci Ctr, State Key Lab Space Weather, Beijing, Peoples R China. (författare)
Zhang, C. Y.Chinese Acad Sci, Natl Space Sci Ctr, State Key Lab Space Weather, Beijing, Peoples R China. (författare)
Chinese Acad Sci, Natl Space Sci Ctr, State Key Lab Space Weather, Beijing, Peoples R China.Austrian Acad Sci, Space Res Inst, Graz, Austria. (creator_code:org_t)

Av författaren/redakt...: Zhang, L. Q.; Baumjohann, W.; Khotyaintsev, Yu ...; Burch, James L.; Webster, J.; Wang, J. Y.; visa fler...; Wang, C.; Dai, L.; Zhang, C. Y.; visa färre...

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