A comparison and review of steady-state and time-varying reconnection

Semenov, V. S.; Kubyshkin, I. V.; Lebedeva, V. V.; Rijnbeek, R. P.; Heyn, Martin; Biernat, H. K.; Farrugia, C. J.

doi:10.1016/0032-0633(92)90150-m

Cited by 48 publications

(19 citation statements)

References 57 publications

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“…Because of their importance in magnetospheric physics, and indeed beyond, the reconnection region is separately reviewed here with regard to Alfvén wave observations. Semenov et al (1992) and Vaivads et al (2006) should be consulted for an in-depth look at the microphysical aspects of reconnection. The reconnection region can be divided into an ion diffusion region and an electron diffusion region which are surrounded by inflow and outflow regions (Fig.…”

Section: Alfvén Waves In the Reconnection Regionmentioning

confidence: 99%

“…In the reconnection region the magnetic field topology is locally changed, but this change is mediated after some time to large parts of the entire magnetosphere. Reconnection is a transient process (e.g., Semenov et al 1992, and references therein) which, at times, can last for several hours (e.g., Frey et al 2003, who analyzed a dayside reconnection event). As such, it should be expected that Alfvén waves with a broad frequency range are launched from the reconnection region (e.g., Song and Lysak 1989;Song 1998).…”

Section: Alfvén Waves In the Reconnection Regionmentioning

confidence: 99%

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Alfvén Waves and Their Roles in the Dynamics of the Earth’s Magnetotail: A Review

2008

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The Earth's magnetotail is an extremely complex system which-energized by the solar wind-displays many phenomena, and Alfvén waves are essential to its dynamics. While Alfvén waves were first predicted in the early 1940's and ample observations were later made with rockets and low-altitude satellites, observational evidence of Alfvén waves in different regions of the extended magnetotail has been sparse until the beginning of the new millennium. Here I provide a phenomenological overview of Alfvén waves in the magnetotail organized by region-plasmasphere, central plasma sheet, plasma sheet boundary layer, tail lobes, and reconnection region-with an emphasis on spacecraft observations reported in the new millennium that have advanced our understanding concerning the roles of Alfvén waves in the dynamics of the magnetotail. A brief discussion of the coupling of magnetotail Alfvén waves and the low-altitude auroral zone is also included.

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Section: Alfvén Waves In the Reconnection Regionmentioning

confidence: 99%

Section: Alfvén Waves In the Reconnection Regionmentioning

confidence: 99%

Alfvén Waves and Their Roles in the Dynamics of the Earth’s Magnetotail: A Review

2008

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“…The simplified MHD description of discontinuities has been successful in explaining low altitude observations of ion and electron signatures (Lockwood et al, 1996). More complicated MHD discontinuities develop when plasmas are different on either side of the current sheet and/or the reconnection is time varying (Semenov et al, 1992; Simplified sketch of a reconnection layer formed by an X-line at the magnetopause. The separatrices are the magnetic field lines connected to the reconnection X-line.…”

Section: Introductionmentioning

confidence: 99%

Separatrix regions of magnetic reconnection at the magnetopause

et al. 2009

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Abstract. Using data from the four Cluster spacecraft we study the separatrix regions of magnetic reconnection sites at the dayside magnetopause under conditions when reconnection is occurring in the magnetopause current layer which separates magnetosheath plasma from the hot magnetospheric plasma sheet. We define the separatrix region as the region between the separatrix -the first field line opened by reconnection -and the reconnection jet (outflow region). We analyze eight separatrix region crossings on the magnetospheric side of the magnetopause and present detailed data for two of the events. We show that characteristic widths of the separatrix regions are of the order of ten ion inertial lengths at the magnetopause. Narrow separatrix regions with widths comparable to a few ion inertial lengths are rare. We show that inside the separatrix region there is a density cavity which sometimes has complex internal structure with multiple density dips. Strong electric fields exist inside the separatrix regions and the electric potential drop across the regions can be up to several kV. On the magnetosheath side of the region there is a density gradient with strong field aligned currents. The observed strong electric fields and currents inside the separatrix region can be important for a local energization of ions and electrons, particularly of ionospheric origin, as well as for magnetosphere-ionosphere coupling.

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“…Based on the 2-D non-steady Petschek-type MHD (magnetohydrodynamics) model (Semenov et al, 1984;Biernat et al, 1987;Semenov et al, 1992;Heyn and Semenov, 1996), the magnetic field and plasma flow configurations are represented analytically as functions of the reconnection electric field (which defines the reconnection rate). Semenov et al (2005a) solved the inverse problem of estimating the reconnection rate from the magnetic field profile in ambient to the plasma flow region -the inflow region.…”

Section: A Alexandrova Et Al: Remote Estimation Of Reconnection Parmentioning

confidence: 99%

Remote estimation of reconnection parameters in the Earth's magnetotail: model and observations

et al. 2012

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Abstract. We develop a method to estimate the reconnected magnetic flux and the location of the reconnection site using properties of magnetic field and plasma velocity disturbances in the regions surrounding the reconnection plasma flow. Our analysis is based on a 3-D non-steady reconnection model with a finite-sized X-line length. In this framework, we obtain a system of equations capturing the relationships between the disturbances of the magnetic field and plasma flow from one side and the reconnection characteristics from another side. These equations allow us to determine the reconnection characteristics from one-point remote observations of the reconnection fast flow, propagated in the magnetotail current sheet. We apply the model to magnetic field and plasma observations at (−43, −11.2, −6.9) R E GSM obtained by the THEMIS/ARTEMIS spacecraft, located in the tail lobe during a substorm event. We found that the reconnection region was located at ∼ (−27, 3.5, 0) R E GSM. The X-line appeared to be close to the local time of the substorm current wedge identified from ground-based observations. We estimated the total magnetic flux, which was reconnected in the event as ∼5 MWb. That corresponds to a small fraction of the total amount of magnetic flux transferred during a substorm.

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A comparison and review of steady-state and time-varying reconnection

Cited by 48 publications

References 57 publications

Alfvén Waves and Their Roles in the Dynamics of the Earth’s Magnetotail: A Review

Alfvén Waves and Their Roles in the Dynamics of the Earth’s Magnetotail: A Review

Separatrix regions of magnetic reconnection at the magnetopause

Remote estimation of reconnection parameters in the Earth's magnetotail: model and observations

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