Low-latitude dayside magnetopause and boundary layer for high magnetic shear: 2. Occurrence of magnetic reconnection

1996 ◽  
Vol 101 (A4) ◽  
pp. 7817-7828 ◽  
Author(s):  
T.-D. Phan ◽  
G. Paschmann ◽  
B. U. Ö. Sonnerup
Keyword(s):  
Boundary Layer ◽  
Magnetic Reconnection ◽  
Low Latitude ◽  
Magnetic Shear ◽  
Dayside Magnetopause

scholarly journals Double Star TC-1 observations of component reconnection at the dayside magnetopause: a preliminary study

2005 ◽  
Vol 23 (8) ◽  
pp. 2889-2895 ◽  
Author(s):  
Z. Y. Pu ◽  
C. J. Xiao ◽  
X. G. Zhang ◽  
Z. Y. Huang ◽  
S. Y. Fu ◽  
...  
Keyword(s):  
Double Star ◽  
Flow Reversal ◽  
Low Latitude ◽  
Magnetic Shear ◽  
Guide Field ◽  
Dayside Magnetopause ◽  
Preliminary Study ◽  
Reconnection Site ◽  
Quadrupolar Field

Abstract. In spring 2004 Double Star TC-1 measured a number of reconnection signatures at the dayside low-latitude magnetopause (MP) when there was a notable By component in the magnetosheath. In a number of events we can show that reconnection was operating nearby TC-1 in the subsolar MP region. In this paper we describe three representative events: (a) event on 21 March 2004 in which the reconnection site can be remotely monitored, the spacecraft was passing by the X-line; (b) event on 12 March 2004 in which TC-1 observed the magnetospheric part of the quadrupolar field, together with a consistent flow reversal; (c) event on 26 March 2004 which occurred for northward IMF, TC-1 observed a reversal of vy across the equatorial MP. In these events the shear angles across the MP were considerably smaller than 180°; a noticeable guide field was present. These observations are consistent with near equatorial component merging, suggesting that component reconnection preferably occurs at the dayside low-latitude MP. There is evidence that when a pronounced magnetic shear across the MP exists in the By component, reconnection may operate at the dayside low-latitude MP for northward IMF Bz.

scholarly journals Magnetopause reconnection across wide local time

2011 ◽  
Vol 29 (9) ◽  
pp. 1683-1697 ◽  
Author(s):  
M. W. Dunlop ◽  
Q.-H. Zhang ◽  
Y. V. Bogdanova ◽  
K. J. Trattner ◽  
Z. Pu ◽  
...  
Keyword(s):  
Magnetic Reconnection ◽  
Large Scale ◽  
Double Star ◽  
Local Times ◽  
Low Latitude ◽  
Guide Field ◽  
Dayside Magnetopause ◽  
Wide Range ◽  
Low Latitudes ◽  
Local Noon

Abstract. During April to July 2007 a combination of 10 spacecraft provided simultaneous monitoring of the dayside magnetopause across a wide range of local times. The array of four Cluster spacecraft, separated at large distances (10 000 km), were traversing the dawn-side magnetopause at high and low latitudes; the five THEMIS spacecraft were often in a 4 + 1 grouped configuration, traversing the low latitude, dusk-side magnetosphere, and the Double star, TC-1 spacecraft was in an equatorial orbit between the local times of the THEMIS and Cluster orbits. We show here a number of near simultaneous conjunctions of all 10 spacecraft at the magnetopause. One conjunction identifies an extended magnetic reconnection X-line, tilted in the low latitude, sub-solar region, which exists together with active anti-parallel reconnection sites extending to locations on the dawn-side flank. Oppositely moving FTE's are observed on all spacecraft, consistent with the initially strong IMF By conditions and the comparative locations of the spacecraft both dusk-ward and dawn-ward of noon. Comparison with other conjunctions of magnetopause crossings, which are also distributed over wide local times, supports the result that reconnection activity may occur at many sites simultaneously across the sub-solar and flank magnetopause, but linked to the large scale (extended) configuration of the merging line; broadly depending on IMF orientation. The occurrence of MR therefore inherently follows a "component" driven scenario irrespective of the guide field conditions. Some conjunctions allow the global magnetopause response to IMF changes to be observed and the distribution of spacecraft can directly confirm its shape, motion and deformation at local noon, dawn and dusk-side, simultaneously.

scholarly journals Mass Loading the Earth's Dayside Magnetopause Boundary Layer and Its Effect on Magnetic Reconnection

2019 ◽  
Vol 46 (12) ◽  
pp. 6204-6213 ◽  
Author(s):  
S. A. Fuselier ◽  
K. J. Trattner ◽  
S. M. Petrinec ◽  
M. H. Denton ◽  
S. Toledo‐Redondo ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Magnetic Reconnection ◽  
Mass Loading ◽  
Dayside Magnetopause

scholarly journals Temperature anisotropies of electrons and two-component protons in the dusk plasma sheet

2007 ◽  
Vol 25 (6) ◽  
pp. 1417-1432 ◽  
Author(s):  
M. N. Nishino ◽  
M. Fujimoto ◽  
T. Terasawa ◽  
G. Ueno ◽  
K. Maezawa ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Solar Wind ◽  
Magnetic Reconnection ◽  
Plasma Sheet ◽  
Cold Plasma ◽  
Strong Anisotropy ◽  
Low Latitude ◽  
Selective Heating ◽  
Two Component ◽  
Low Latitude Boundary Layer

Abstract. To investigate the cold plasma sheet formation under northward IMF, we study the temperature anisotropies of electrons and two-component protons observed by the Geotail spacecraft. The two-component protons, which are occasionally observed in the dusk plasma sheet near the low-latitude boundary, are the result of spatial mixing of the hot protons of the magnetosphere proper and the cold protons from the solar wind. Recent research focusing on the two-component protons reported that the cold proton component at times has a strong anisotropy, and that the sense of the anisotropy depends on the observed locations. Since electrons have been known to possess a strong parallel anisotropy around the low-latitude boundary layer, we compare anisotropies of electrons and protons to find that the strengths of parallel anisotropies of electrons and the cold proton component are in good correlation in the tail flank. The parallel anisotropy of electrons is stronger than that of the cold proton component, which is attributed to selective heating of electrons. We further find that the strengths of the parallel anisotropies in the tail flank depend on the latitudinal angle of the IMF; strong parallel anisotropies occur under strongly northward IMF. We discuss that the Kelvin-Helmholtz vortices, which developed under strongly northward IMF, and the resultant magnetic reconnection therein may lead to the strong parallel anisotropies observed in the tail flank.

scholarly journals Coordinated Cluster/Double Star observations of dayside reconnection signatures

2005 ◽  
Vol 23 (8) ◽  
pp. 2867-2875 ◽  
Author(s):  
M. W. Dunlop ◽  
M. G. G. T. Taylor ◽  
J. A. Davies ◽  
C. J. Owen ◽  
F. Pitout ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Double Star ◽  
Low Latitude ◽  
Flux Transfer Events ◽  
Reconnection Region ◽  
Dayside Magnetopause ◽  
First Results ◽  
North And South ◽  
Imf Clock Angle

Abstract. The recent launch of the equatorial spacecraft of the Double Star mission, TC-1, has provided an unprecedented opportunity to monitor the southern hemisphere dayside magnetopause boundary layer in conjunction with northern hemisphere observations by the quartet of Cluster spacecraft. We present first results of one such situation where, on 6 April 2004, both Cluster and the Double Star TC-1 spacecraft were on outbound transits through the dawnside magnetosphere. The observations are consistent with ongoing reconnection on the dayside magnetopause, resulting in a series of flux transfer events (FTEs) seen both at Cluster and TC-1, which appear to lie north and south of the reconnection line, respectively. In fact, the observed polarity and motion of each FTE signature advocates the existence of an active reconnection region consistently located between the positions of Cluster and TC-1, with Cluster observing northward moving FTEs with +/- polarity, whereas TC-1 sees -/+ polarity FTEs. This assertion is further supported by the application of a model designed to track flux tube motion for the prevailing interplanetary conditions. The results from this model show, in addition, that the low-latitude FTE dynamics are sensitive to changes in convected upstream conditions. In particular, changing the interplanetary magnetic field (IMF) clock angle in the model suggests that TC-1 should miss the resulting FTEs more often than Cluster and this is borne out by the observations.

scholarly journals Cluster multispacecraft observations at the high-latitude duskside magnetopause: implications for continuous and component magnetic reconnection

2005 ◽  
Vol 23 (2) ◽  
pp. 461-473 ◽  
Author(s):  
A. Retinò ◽  
M. B. Bavassano Cattaneo ◽  
M. F. Marcucci ◽  
A. Vaivads ◽  
M. André ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Magnetic Reconnection ◽  
Interplanetary Magnetic Field ◽  
Tangential Stress ◽  
High Latitude ◽  
Magnetic Shear ◽  
Magnetospheric Boundary ◽  
Flow Reversals ◽  
The Imf

Abstract. We report multispacecraft Cluster observations of magnetic reconnection at the high-latitude magnetopause/magnetospheric boundary layer (MP/BL) under mainly northward interplanetary magnetic field (IMF) conditions. The event we study is on 3 December 2001 when the Cluster spacecraft were skimming the high-latitude duskside MP/BL during a period of about four hours. The orbit and configuration of the spacecraft were such that at least one satellite was present in the MP/BL during most of that period. We present the evidence of reconnection in the form of tangential stress balance between the magnetosheath and the MP/BL (Walén test) and in several cases in the form of transmitted magnetosheath ions in the MP/BL and incident/reflected magnetosheath ions in the magnetosheath boundary layer (MSBL) . The observations are consistent with magnetic reconnection occurring tailward of the cusp and going on continuously for a period of about four hours. The observed directions of the reconnection flows are consistent with the IMF orientation, thus indicating that reconnection is globally controlled by the IMF. Observations of a few flow reversals suggest passages of the spacecraft close to the X-line. The observation of low magnetic shear across the magnetopause during a flow reversal is consistent with component merging at least in one case. The observation of reconnection flows on the duskside magnetopause irrespective of the change in the sign of the IMF BY also suggests a better agreement with the component merging model, though antiparallel merging cannot be excluded because the distance from the X-line is not known.

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