Features of separatrix regions in magnetic reconnection: Comparison of 2‐D particle‐in‐cell simulations and Cluster observations

Lu, Quanming; Huang, Can; Xie, Jinlin; Wang, Rongsheng; Wu, Mingyu; Vaivads, A.; Wang, Shui

doi:10.1029/2010ja015713

Cited by 97 publications

(128 citation statements)

References 36 publications

Supporting

Mentioning

107

Contrasting

Unclassified

Order By: Relevance

“…The current in the reconnection plane is dominated by electron motion [32]. In anti-parallel magnetic reconnection, electrons stream along the separatrices from the strong magnetic field region into the X-line region where electrons are accelerated by the reconnection electric field.…”

Section: Characteristics Of the Reconnection Diffusion Regionmentioning

confidence: 99%

“…In anti-parallel magnetic reconnection, electrons stream along the separatrices from the strong magnetic field region into the X-line region where electrons are accelerated by the reconnection electric field. The accelerated electrons flow out along the magnetic field lines on the inside of the separatrices [21,32]. Thus, a current system is formed that streams out along the separatrices and flows into the X-line along these magnetic field lines inside the separatrices [23,32].…”

Section: Characteristics Of the Reconnection Diffusion Regionmentioning

confidence: 99%

“…The accelerated electrons flow out along the magnetic field lines on the inside of the separatrices [21,32]. Thus, a current system is formed that streams out along the separatrices and flows into the X-line along these magnetic field lines inside the separatrices [23,32]. The out-of-plane magnetic field created by the current system will be cancelled, while a quadrupolar structure is formed inside the ion diffusion region [14,23,32].…”

Section: Characteristics Of the Reconnection Diffusion Regionmentioning

confidence: 99%

See 2 more Smart Citations

Electron dynamics in collisionless magnetic reconnection

Wang

Xie

et al. 2011

Chin. Sci. Bull.

Self Cite

View full text Add to dashboard Cite

Magnetic reconnection provides a physical mechanism for fast energy conversion from magnetic energy to plasma kinetic energy. It is closely associated with many explosive phenomena in space plasma, usually collisionless in character. For this reason, researchers have become more interested in collisionless magnetic reconnection. In this paper, the various roles of electron dynamics in collisionless magnetic reconnection are reviewed. First, at the ion inertial length scale, ions and electrons are decoupled. The resulting Hall effect determines the reconnection electric field. Moreover, electron motions determine the current system inside the reconnection plane and the electron density cavity along the separatrices. The current system in this plane produces an out-of-plane magnetic field. Second, at the electron inertial length scale, the anisotropy of electron pressure determines the magnitude of the reconnection electric field in this region. The production of energetic electrons, which is an important characteristic during magnetic reconnection, is accelerated by the reconnection electric field. In addition, the different topologies, temporal evolution and spatial distribution of the magnetic field affect the accelerating process of electrons and determine the final energy of the accelerated electrons. Third, we discuss results from simulations and spacecraft observations on the secondary magnetic islands produced due to secondary instabilities around the X point, and the associated energetic electrons. Furthermore, progress in laboratory plasma studies is also discussed in regard to electron dynamics during magnetic reconnection. Finally, some unresolved problems are presented. Magnetic reconnection provides an effective mechanism for fast conversion of magnetic energy into plasma kinetic energy. Simultaneously, the topology of magnetic field changes [1][2][3]. First proposed by Giovanelli, magnetic reconnection is related to many explosive phenomena, such as solar flares, magnetospheric substorms, and disruptive instabilities in Tokamak plasmas [4][5][6][7][8]. Giovanelli thought discharge phenomena would occur around the neutral line or point where the magnetic field vanishes, an idea that could be very important in solar-flare production [9]. In 1958, Dungey first introduced the concept of "magnetic reconnection" , applying it in the construction of the open *Corresponding author (email: qmlu@ustc.edu.cn) Earth magnetosphere model [10]. The first magnetic reconnection model was proposed by Sweet and Parker, separately. In this model, plasma and magnetic field flow into the center of the current sheet from both sides where magnetic field lines are cut off and reconnected. Magnetic energy is converted into plasma kinetic energy; energized plasma then flows out of the region from both ends [11,12]. However, the predicted reconnection rate in this model is so low that it is unable to account for the explosive phenomena in space. Petschek improved the Sweet-Parker model and suggested that magnetic reconnecti...

show abstract

Section: Characteristics Of the Reconnection Diffusion Regionmentioning

confidence: 99%

Section: Characteristics Of the Reconnection Diffusion Regionmentioning

confidence: 99%

Section: Characteristics Of the Reconnection Diffusion Regionmentioning

confidence: 99%

See 1 more Smart Citation

Electron dynamics in collisionless magnetic reconnection

Wang

Xie

et al. 2011

Chin. Sci. Bull.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Separatrices are thin boundary layers between plasmas with different properties (density, temperature, and flow pattern) [1][2][3] and subject to instabilities, wave activity and turbulence [4][5][6]. One of the distinctive features of collisionless magnetic reconnection is the formation of localized low density regions along the separatrices [7,8]. These depletion areas are called cavities.…”

Section: Introductionmentioning

confidence: 99%

Three dimensional density cavities in guide field collisionless magnetic reconnection

Lapenta

Divin

Goldman³

et al. 2012

Physics of Plasmas

View full text Add to dashboard Cite

Particle-in-Cell simulations of collisionless magnetic reconnection with a guide field reveal for the first time the three dimensional features of the low density regions along the magnetic reconnection separatrices, the so-called cavities. It is found that structures with further lower density develop within the cavities. Because their appearance is similar to the rib shape, these formations are here called low density ribs. Their location remains approximately fixed in time and their density progressively decreases, as electron currents along the cavities evacuate them. They develop along the magnetic field lines and are supported by a strong perpendicular electric field that oscillates in space. In addition, bipolar parallel electric field structures form as isolated spheres between the cavities and the outflow plasma, along the direction of the low density ribs and of magnetic field lines.

show abstract

“…On the same field lines, higher energy electrons have also been reported to be directed away from the diffusion region Nagai et al, 2001;Wang et al, 2010a). Such a configuration has also been confirmed by Lu et al (2010) who showed that the electron density depletions formed along the separatrices are outside the peaks of the out-of-plane magnetic field.…”

Section: Introductionmentioning

confidence: 53%

On the retreat of near-Earth neutral line during substorm expansion phase: a THEMIS case study during the 9 January 2008 substorm

Cao

et al. 2012

Ann. Geophys.

View full text Add to dashboard Cite

Abstract. The location of magnetic reconnection in the midtail during a substorm was studied in many researches. Here we present multi-point THEMIS observations of a reconnection event in the near-Earth magnetotail during substorm. In this event, THEMIS probes stayed in the near-Earth and midtail region aligning along the magnetotail. This allows reconnection evolution to be probed simultaneously from about −10 R E to −23 R E down tail. The Hall current related electron streams were observed at the same time by two probes far away from the reconnection site. Before near-Earth reconnection involved the tail lobe magnetic field, the reconnection site was restricted in earthward −23 R E . When reconnection involved into the tail lobe region, the reconnection site started to retreat gradually.

show abstract

Features of separatrix regions in magnetic reconnection: Comparison of 2‐D particle‐in‐cell simulations and Cluster observations

Cited by 97 publications

References 36 publications

Electron dynamics in collisionless magnetic reconnection

Electron dynamics in collisionless magnetic reconnection

Three dimensional density cavities in guide field collisionless magnetic reconnection

On the retreat of near-Earth neutral line during substorm expansion phase: a THEMIS case study during the 9 January 2008 substorm

Contact Info

Product

Resources

About