Asymmetry in the current sheet and secondary magnetic flux ropes during guide field magnetic reconnection

Magnetic reconnection is a fundamental plasma process, by which magnetic energy is explosively released in the current sheet to energize charged particles and to create bi-directional Alfv&#233;nic plasma jets. A long-outstanding issue is how the stored magnetic energy is rapidly released in the process. Numerical simulations and observations show that formation and interaction of magnetic flux ropes dominate the evolution of the reconnecting current sheet. Accordingly, most volume of the reconnecting current sheet is occupied by the flux ropes and energy dissipation primarily occurs along their edges via the flux rope coalescence. Here, for the first time, we present in-situ evidence of magnetic reconnection inside the filamentary currents which was driven possibly by electron vortices inside the flux ropes. Our results reveal an important new way for energy dissipation in magnetic reconnection.

Download Full-text

Interaction of Magnetic Flux Ropes Via Magnetic Reconnection Observed at the Magnetopause

Journal of Geophysical Research Space Physics ◽

10.1002/2017ja024482 ◽

2017 ◽

Vol 122 (10) ◽

pp. 10,436-10,447 ◽

Cited By ~ 11

Author(s):

Rongsheng Wang ◽

Quanming Lu ◽

Rumi Nakamura ◽

Wolfgang Baumjohann ◽

C. T. Russell ◽

...

Keyword(s):

Magnetic Flux ◽

Magnetic Reconnection ◽

Magnetic Flux Ropes ◽

Flux Ropes

Download Full-text

Observations of magnetic flux ropes during magnetic reconnection in the Earth's magnetotail

Annales Geophysicae ◽

10.5194/angeo-30-761-2012 ◽

2012 ◽

Vol 30 (5) ◽

pp. 761-773 ◽

Cited By ~ 38

Author(s):

A. L. Borg ◽

M. G. G. T. Taylor ◽

J. P. Eastwood

Keyword(s):

Magnetic Flux ◽

Magnetic Reconnection ◽

Electron Flux ◽

Energetic Electron ◽

Flux Rope ◽

Clear Correlation ◽

Particle Measurements ◽

Magnetic Flux Ropes ◽

Flux Ropes ◽

Show Evidence

Abstract. We present an investigation of magnetic flux ropes observed by the four Cluster spacecraft during periods of magnetic reconnection in the Earth's magnetotail. Using a list of 21 Cluster encounters with the reconnection process in the period 2001–2006 identified in Borg et al. (2012), we present the distribution and characteristics of the flux ropes. We find 27 flux ropes embedded in the reconnection outflows of only 11 of the 21 reconnection encounters. Reconnection processes associated with no flux rope observations were not distinguishable from those where flux ropes were observed. Only 7 of the 27 flux ropes show evidence of enhanced energetic electron flux above 50 keV, and there was no clear signature of the flux rope in the thermal particle measurements. We found no clear correlation between the flux rope core field and the prevailing IMF By direction.

Download Full-text

Non-Gaussianity and cross-scale coupling in interplanetary magnetic field turbulence during a rope–rope magnetic reconnection event

Annales Geophysicae ◽

10.5194/angeo-36-497-2018 ◽

2018 ◽

Vol 36 (2) ◽

pp. 497-507 ◽

Cited By ~ 1

Author(s):

Rodrigo A. Miranda ◽

Adriane B. Schelin ◽

Abraham C.-L. Chian ◽

José L. Ferreira

Keyword(s):

Magnetic Field ◽

Magnetic Flux ◽

Magnetic Reconnection ◽

Coherent Structures ◽

Flux Rope ◽

Inertial Subrange ◽

Order Moment ◽

Magnetic Flux Ropes ◽

Flux Ropes ◽

Non Gaussian

Abstract. In a recent paper (Chian et al., 2016) it was shown that magnetic reconnection at the interface region between two magnetic flux ropes is responsible for the genesis of interplanetary intermittent turbulence. The normalized third-order moment (skewness) and the normalized fourth-order moment (kurtosis) display a quadratic relation with a parabolic shape that is commonly observed in observational data from turbulence in fluids and plasmas, and is linked to non-Gaussian fluctuations due to coherent structures. In this paper we perform a detailed study of the relation between the skewness and the kurtosis of the modulus of the magnetic field |B| during a triple interplanetary magnetic flux rope event. In addition, we investigate the skewness–kurtosis relation of two-point differences of |B| for the same event. The parabolic relation displays scale dependence and is found to be enhanced during magnetic reconnection, rendering support for the generation of non-Gaussian coherent structures via rope–rope magnetic reconnection. Our results also indicate that a direct coupling between the scales of magnetic flux ropes and the scales within the inertial subrange occurs in the solar wind. Keywords. Space plasma physics (turbulence)

Download Full-text

Magnetic Reconnection in the Corona as a Source of Switchbacks in the Solar Wind

10.5194/egusphere-egu21-2865 ◽

2021 ◽

Author(s):

James Drake ◽

Oleksiy Agapitov ◽

Marc Swisdak ◽

Sam Badman ◽

Stuart Bale ◽

...

Keyword(s):

Solar Wind ◽

Magnetic Reconnection ◽

Coronal Hole ◽

Flux Rope ◽

Magnetic Flux Ropes ◽

Guide Field ◽

Large Numbers ◽

Flux Ropes ◽

Environment Characteristic ◽

Field Lines

The observations from the Parker Solar Probe during the first perihelion revealed large numbers of local reversals in the radial component of the magnetic field with associated velocity spikes. Since the spacecraft was magnetically connected to a coronal hole during the closest approach to the sun, one possible source of these spikes is magnetic reconnection between the open field lines in the coronal hole and an adjacent region of closed flux. Reconnection in a low beta environment characteristic of the corona is expected to be bursty rather than steady and is therefore capable of producing large numbers of magnetic flux ropes with local reversals of the radial magnetic field that can propagate outward large radial distances from the sun. Flux ropes with a strong guide field produce signatures consistent with the PSP observations. We have carried out simulations of "interchange" reconnection in the corona and have explored the local structure of flux ropes embedded within the expanding solar wind. We have first established that traditional interchange reconnection cannot produce the switchbacks since bent field lines generated in the corona quickly straighten. The simulations have been extended to the regime dominated by the production of multiple flux ropes and we have established that flux ropes are injected into the local solar wind. Local simulations of reconnection are also being carried out to explore the structure of flux ropes embedded in the solar wind for comparison with observations. Evidence is presented that flux rope merging may be ongoing and might lead to the high aspect ratio of the switchback structures measured in the solar wind.

Download Full-text