Global-scale hybrid simulation of dayside magnetic reconnection under southward IMF: Structure and evolution of reconnection

Tan, B.; Lin, Y.; Perez, J. D.; Wang, X. Y.

doi:10.1029/2010ja015580

Cited by 43 publications

(79 citation statements)

References 41 publications

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“…In the positive dipole tilt case, FTE signatures were observed in both the Northern and Southern Hemispheres. The lack of a bias toward the Southern (winter) Hemisphere appears to contradict the Raeder [2006] results, although we note that the dipole tilt used by Tan et al [2011] was less than half that used by Raeder [2006]. FTEs were also observed in the zero dipole tilt case, which is inconsistent with Raeder [2006].…”

Section: Introductioncontrasting

confidence: 69%

“…(While the Dorelli and Bhattacharjee [2009] simulation was carried out for an IMF clock angle of 135°, they noted that preliminary investigations of the purely southward IMF case led to similar but more complex topologies.) Recently, Tan et al [2011] used a global‐scale hybrid simulation to investigate the effect of dipole tilt. They reported the results of two model runs; the IMF was purely southward in both cases, but the dipole tilt was +15° in one case and zero in the other.…”

Section: Introductionmentioning

confidence: 99%

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Seasonal and clock angle control of the location of flux transfer event signatures at the magnetopause

2012

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[1] Most models of flux transfer event (FTE) formation produce pairs of structures which in general move away from the subsolar region and give rise to signatures which can be observed in both the Northern and Southern Hemispheres. The multiple reconnection line (X line) model is unusual as a reconnection-based model that is capable of producing a single flux rope if only two X lines are present. Raeder (2006) reported the results of an MHD simulation where he studied the effect of the Earth's dipole tilt on reconnection at the dayside magnetopause for a southward IMF orientation; in his simulations, flux ropes were formed by the sequential formation of X lines, and when the dipole tilt was set to a value representative of solstice the flux ropes moved preferentially toward the winter hemisphere. Some observational evidence has previously been presented for a bias toward FTE signatures being observed in the winter hemisphere; in this paper, we present further observational evidence for this phenomenon, using an independently derived data set. Once the seasonal bias is taken into account, we find that the IMF clock angle controls the location of FTE signatures. We also find that the effective dipole tilt (combining the geomagnetic dipole tilt with the IMF tilt angle) provides no clear control of the location of FTE signatures.

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Section: Introductioncontrasting

confidence: 69%

Section: Introductionmentioning

confidence: 99%

Seasonal and clock angle control of the location of flux transfer event signatures at the magnetopause

2012

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“…On the other hand, other global hybrid as well as MHD simulations show that FTEs can be created with no dipole tilt (Omidi and Sibeck, 2007;Dorelli and Bhattacharjee, 2009;Tan et al, 2011). A key difference from Raeder's simulations is the way electrical or numerical resistivity is imposed in the simulations: in the MHD simulation by Dorelli and Bhattacharjee (2009), as high a spatial resolution as possible was used; in the 2D hybrid simulations by Omidi and Sibeck (2007), a spatially uniform resistivity was imposed; whereas the 3D hybrid simulations by Tan et al (2011) prescribed a resistivity that was proportional to the current density.…”

Section: Temporal Aspects Of Magnetopause Reconnectionmentioning

confidence: 99%

“…A key difference from Raeder's simulations is the way electrical or numerical resistivity is imposed in the simulations: in the MHD simulation by Dorelli and Bhattacharjee (2009), as high a spatial resolution as possible was used; in the 2D hybrid simulations by Omidi and Sibeck (2007), a spatially uniform resistivity was imposed; whereas the 3D hybrid simulations by Tan et al (2011) prescribed a resistivity that was proportional to the current density. How the reconnection electric field arises and is sustained, and how in reality it is related to the current density are poorly understood.…”

Section: Temporal Aspects Of Magnetopause Reconnectionmentioning

confidence: 99%

Structure and Dynamics of the Magnetopause and Its Boundary Layers

Hasegawa¹

2012

Monogr. Environ. Earth Planets

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The magnetopause is the key region in space for the transfer of solar wind mass, momentum, and energy into the magnetosphere. During the last decade, our understanding of the structure and dynamics of Earth's magnetopause and its boundary layers has advanced considerably, thanks largely to the advent of multi-spacecraft missions such as Cluster and THEMIS. Moreover, various types of physics-based techniques have been developed for visualizing two-or threedimensional plasma and field structures from data taken by one or more spacecraft, providing a new approach to the analysis of the spatiotemporal properties of magnetopause processes, such as magnetic reconnection and the Kelvin-Helmholtz instability (KHI). Information on the size, shape, orientation, and evolution of magnetic flux ropes or flow vortices generated by those processes can be extracted from in situ measurements. Observations show that magnetopause reconnection can be globally continuous for both southward and northward interplanetary magnetic field (IMF) conditions, but even under such circumstances, more than one X-line may exist within a certain (low-latitude or high-latitude) portion on the magnetopause and some X-lines may retreat anti-sunward. The potential global effects of such behavior are discussed. An overview is also given of the identification, excitation, evolution, and possible consequences of the magnetopause KHI: there is evidence for nonlinear KHI growth and associated vortex-induced reconnection under northward IMF. Observation-based estimates indicate that reconnection tailward of both polar cusps can be the dominant mechanism for solar wind plasma entry into the dayside magnetosphere under northward IMF. However, the mechanism by which the transferred plasma is transported into the central portion of the magnetotail, and the role of magnetopause processes in this transport, remain unclear. Future prospects of magnetopause and other relevant studies are also discussed.

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“…Large-scale simulations of FTE were published; for example, the works of Raeder [2006] and Fedder et al [2002] help understand the geometry, the topology, and the conditions for FTE formation. Energetic electrons trapped between two hemispheres were identified in global hybrid simulations by Tan et al [2011]. Dorelli and Bhattacharjee [2009] have conducted resistive MHD simulations of the formation and topology of FTEs.…”

Section: Introductionmentioning

confidence: 99%

What is the nature of magnetosheath FTEs?

et al. 2015

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Cluster multipoint measurements are used to study two successive magnetosheath flux transfer events (FTEs). Magnetic field lines in the leading region are found to be closed magnetospheric field lines. For event 1 these field lines are wounded up by a large current structure oriented eastward and moving poleward. Conversely, the trailing region corresponds to opened magnetic field lines. For both events the leading edge of the FTEs is a tangential discontinuity separating the magnetosheath from closed field lines. In the case of event 1 magnetosheath ions are accelerated through the FTE trailing edge via a rotational discontinuity and penetrate on closed field lines through a second discontinuity. Thus, the ion jet is accelerated equatorward of the spacecraft but the backtracking of the discontinuities and the lack of dispersion show that ion acceleration occurs at less than 2 RE from Cluster. On the other hand the extrapolation forward indicates that the FTE bulge steepens as in simulations of Dorelli and Bhattacharjee (). Evidence is given for the penetration of magnetosheath ions inside the core of the FTE, on closed field lines. Magnetosheath electrons are accelerated in parallel and antiparallel directions on open and on closed field lines, thus breaking the frozen‐in condition. Event 2 is also split in two distinct regions but no evidence is found for accelerated bidirectional magnetosheath electrons. For event 2 the two discontinuities at the trailing region are stacked together when they are crossed by the spacecraft, suggesting that the current splitting is a reconnection signature.

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Global-scale hybrid simulation of dayside magnetic reconnection under southward IMF: Structure and evolution of reconnection

Cited by 43 publications

References 41 publications

Seasonal and clock angle control of the location of flux transfer event signatures at the magnetopause

Seasonal and clock angle control of the location of flux transfer event signatures at the magnetopause

Structure and Dynamics of the Magnetopause and Its Boundary Layers

What is the nature of magnetosheath FTEs?

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