Tail reconnection region versus auroral activity inferred from conjugate ARTEMIS plasma sheet flow and auroral observations. Issue 9 (23rd September 2013)

• Record Type: Journal Article
• Authors: Nishimura, Y.; Lyons, L. R.; Xing, X.; Angelopoulos, V.; Donovan, E. F.; Mende, S. B.; Bonnell, J. W.; Auster, U.
• Is Part Of: Journal of geophysical research. Volume 118:Issue 9(2013:Sep.)
• Page Start: 5758
• Page End: 5766
• Publication Date: 2013-09-23
• Subjects: poleward boundary intensifications -- auroral streamers -- THEMIS ASI -- ARTEMIS -- distant neutral line -- near‐Earth neutral line; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1002/jgra.50549
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: [1] Plasma sheet flow bursts have been suggested to correspond to different types of auroral activity, such as poleward boundary intensifications (PBIs), ensuing auroral streamers, and substorms. The flow‐aurora association leads to the important question of identifying the magnetotail source region for the flow bursts and how this region depends on magnetic activity. The present study uses the ARTEMIS spacecraft coordinated with conjugate ground‐based auroral imager observations to identify flow bursts beyond 45 R E downtail and corresponding auroral forms. We find that quiet‐time flows are directed dominantly earthward with a one‐to‐one correspondence with PBIs. Flow bursts during the substorm recovery phase and during steady magnetospheric convection (SMC) periods are also directed earthward, and these flows are associated with a series of PBIs/streamers lasting for tens of minutes with similar durations to that of the series of earthward flows. Presubstorm onset flows are also earthward and associated with PBIs/streamers. The earthward flows during those magnetic conditions suggest that the flow bursts, which lead to PBIs and streamers, originate from further downtail of ARTEMIS, possibly from the distant‐tail neutral line (DNL) or tailward‐retreated near‐Earth neutral line (NENL) rather than from the nominal NENL location in the midtail. We find that tailward flows are limited primarily to the substorm expansion phase. They continue throughout the period of auroral poleward expansion, indicating that the expansion‐phase flows originate from the NENL and that NENL activity is closely related to the auroral expansion of the substorm expansion phase. Key Points: Magnetic activity dependence of aurora‐distant tail flow relation is determined Quiet, recovery and SMCs flows originate from DNL and linked to PBIs/streamers Expansion‐phase flows are directed tailward and drive poleward expanding aurora