Electromagnetic Fluctuations during Fast Reconnection in a Laboratory Plasma

Ji, Hantao; Terry, S. D.; Yamada, Masaaki; Kulsrud, Russell M.; Kuritsyn, A.; Ren, Y.

doi:10.1103/physrevlett.92.115001

Cited by 200 publications

(217 citation statements)

References 35 publications

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“…7). Both these results confirm an importance of the non-MHD effects in the magnetic field reconnection as presented in the papers by Ji et al (2004) and Ren et al (2005).…”

Section: Discussionsupporting

confidence: 77%

“…Because in our study we use the PIC simulation we decided to check the findings made by Ji et al (2004) and Ren et al (2005) saying that in the collisionless regime of the magnetic field reconnection there are important non-MHD effects. Therefore, in agreement with these papers, we checked a structure of the magnetic field in reconnecting current sheets.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Fragmentation during merging of plasmoids in the magnetic field reconnection

Karlický

Bárta

Nickeler

2012

A&A

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Context. Application of the magnetic-reconnection theory onto large-scale events, such as solar flares, requires formation of very thin (kinetic-scale) current sheets within the rather thick flare current layer. Hence, some fragmentation/filamentation mechanisms has to be in action. Aims. We aim at identifying fragmentation mechanisms for magnetic field and current density structures. Namely, we focus at detailed study of the processes during the merging of plasmoids that had been formed in the current layer. Methods. A 2.5-D electromagnetic particle-in-cell model is used and its results analysed. Results. It is shown that the merging process of plasmoids is not a simple process as presented in some previous studies. On the contrary, this process leads to a complex fragmentation. We found two types of fragmentation processes: a) fragmentation in the current sheet generated between the merging plasmoids and b) fragmentation at the boundary of plasma outflow from the reconnection between these plasmoids. While the first type of fragmentation is generated by the tearing-mode (plasmoid) instability of the secondary current sheet, the second one looks to be connected with an increase of the plasma β parameter during these processes. Thus, sheared high-β plasma flows produce this additional fragmentation. Conclusions. The fragmentation and energy transport from large to small scales in a large-scale magnetic reconnection seem to be the result of interplay and positive feedback between instabilities driven by high gradients in both magnetic (intense current density) and velocity (high vorticity) fields.

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“…7). Both these results confirm an importance of the non-MHD effects in the magnetic field reconnection as presented in the papers by Ji et al (2004) and Ren et al (2005).…”

Section: Discussionsupporting

confidence: 77%

Section: Discussionmentioning

confidence: 99%

Fragmentation during merging of plasmoids in the magnetic field reconnection

Karlický

Bárta

Nickeler

2012

A&A

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“…Recent laboratory experiments appear to show a positive correlation between the reconnection rate and the magnitude of electro-magnetic fluctuations up to the lower hybrid frequency [5], which casts doubt on the role Hall effects play in controlling the rate of fast reconnection. Using small hybrid simulations, it has been concluded that although a turbulent configuration can arise in 3D, this does not significantly enhance the reconnection rate [6].…”

mentioning

confidence: 99%

Observations of Turbulence Generated by Magnetic Reconnection

et al. 2009

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Spacecraft observations of turbulence within a magnetic reconnection (guide field ∼ 0) ion diffusion region are presented. In the inertial subrange, electric and magnetic fluctuations both followed a -5/3 power law; at higher frequencies, the spectral indices were -1 and -8/3 respectively. The dispersion relation was found to be consistent with fast mode/whistler waves rather than kinetic Alfvén/ion cyclotron waves. Lower hybrid waves, which could be enhanced by whistler mode conversion, were observed but the associated anomalous resistivity was not found to significantly modify the reconnection rate.

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“…The source of the waves was related to the outflow region of the reconnection site. Ji et al (2004) have observed right-hand polarized whistler inside the current sheet, which propagates along the current sheet, and becomes trapped in the perpendicular direction, in a high-β laboratory plasma. Generation of such whistler waves in a high-β plasma can be attributed to MTSI (modified two stream instability), caused by perpendicular currents.…”

Section: Discussionmentioning

confidence: 99%

“…One such instability is a modified two-stream instability (MTSI) (Krall and Liewer, 1971;Wu et al, 1983;Silveira et al, 2002), which results from a relative drift of magnetized electrons and unmagnetized ions (v d ∼V A ). Recently, Ji et al (2004) reported on the correlation of whistler waves driven by MTSI and the enhancement of reconnection rates in a high-β laboratory plasma. Observation of enhanced whistlermode waves in association with a reconnection event on the dayside magnetopause was reported by Deng and Matsumoto (2001).…”

Section: Introductionmentioning

confidence: 99%

Cluster observations of high-frequency waves in the exterior cusp

et al. 2004

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Abstract.We study wave emissions, in the frequency range from above the lower hybrid frequency up to the plasma frequency, observed during one of the Cluster crossings of a high-beta exterior cusp region on 4 March 2003. Waves are localized near narrow current sheets with a thickness a few times the ion inertial length; currents are strong, of the order of 0.1-0.5 µA/m 2 (0.1-0.5 mA/m 2 when mapped to ionosphere). The high frequency part of the waves, frequencies above the electron-cyclotron frequency, is analyzed in more detail. These high frequency waves can be broad-band, can have spectral peaks at the plasma frequency or spectral peaks at frequencies below the plasma frequency. The strongest wave emissions usually have a spectral peak near the plasma frequency. The wave emission intensity and spectral character change on a very short time scale, of the order of 1 s. The wave emissions with strong spectral peaks near the plasma frequency are usually seen on the edges of the narrow current sheets. The most probable generation mechanism of high frequency waves are electron beams via bump-on-tail or electron two-stream instability. Buneman and ion-acoustic instability can be excluded as a possible generation mechanism of waves. We suggest that high frequency waves are generated by electron beams propagating along the separatrices of the reconnection region.

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Electromagnetic Fluctuations during Fast Reconnection in a Laboratory Plasma

Cited by 200 publications

References 35 publications

Fragmentation during merging of plasmoids in the magnetic field reconnection

Fragmentation during merging of plasmoids in the magnetic field reconnection

Observations of Turbulence Generated by Magnetic Reconnection

Cluster observations of high-frequency waves in the exterior cusp

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