Dayside magnetopause reconnection and flux transfer events: BepiColombo earth-Flyby observations

Abstract. This study analyzes the flux transfer event (FTE)-type flux ropes and magnetic reconnection around the dayside magnetopause during BepiColombo’s Earth flyby. The magnetosheath corresponds to a high plasma β (~ 8) and the IMF has a significant radial component. Six flux ropes are identified. The motion of flux rope together with the maximum magnetic shear model suggests that the reconnection X-line swipes BepiColombo near the magnetic equator due to an increase of the radial IMF. The flux rope with the highest flux content contains a clear coalescence signature, i.e., two smaller flux ropes merging, supporting theoretical predictions the flux content of flux ropes can grow through coalescence. The secondary reconnection associated with coalescence exhibits a large normalized guide field and a reconnection rate comparable to the reconnection rate measured at the magnetopause (~ 0.1).

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Dayside Magnetopause Reconnection and Flux Transfer Events: BepiColombo Earth-Flyby

10.5194/egusphere-egu21-3424 ◽

2021 ◽

Author(s):

Wei-Jie Sun ◽

James Slavin ◽

Rumi Nakamura ◽

Daniel Heyner ◽

Johannes Mieth

Keyword(s):

Magnetic Field ◽

Large Scale ◽

European Space Agency ◽

Flux Rope ◽

Transfer Event ◽

Flux Transfer Events ◽

Space Agency ◽

Flux Ropes ◽

Flux Transfer ◽

Magnetospheric Multiscale Mission

BepiColombo is a joint mission of the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA) to the planet Mercury. The BepiColombo mission consists of two spacecraft, which are the Mercury Planetary Orbiter (MPO) and Mercury Magnetospheric Orbiter (Mio). The mission made its first planetary flyby, which is the only Earth flyby, on 10 April 2020, during which several instruments collected measurements. In this study, we analyze MPO magnetometer (MAG) observations of Flux Transfer Events (FTEs) in the magnetosheath and the structure of the subsolar magnetopause near the &#160;flow stagnation point. The magnetosheath plasma beta was high with a value of ~ 8 and the interplanetary magnetic field (IMF) was southward with a clock angle that decreased from ~ 100 degrees to ~ 150 degrees. &#160;As the draped IMF became increasingly southward several of the flux transfer event (FTE)-type flux ropes were observed. These FTEs traveled southward indicating that the magnetopause X-line was located northward of the spacecraft, which is consistent with a dawnward tilt of the IMF. Most of the FTE-type flux ropes were in ion-scale, <10 s duration, suggesting that they were newly formed. Only one large-scale FTE-type flux rope, ~ 20 s, was observed. It was made up of two successive bipolar signatures in the normal magnetic field component, which is evidence of coalescence at a secondary reconnection site. Further analysis demonstrated that the dimensionless reconnection rate of the re-reconnection associated with the coalescence site was ~ 0.14. While this investigation was limited to the MPO MAG observations, it strongly supports a key feature of dayside reconnection discovered in the Magnetospheric Multiscale mission, the growth of FTE-type flux ropes through coalescence at secondary reconnection sites.

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Multiple flux rope events at the magnetopause observations by TC-1 on 18 March 2004

Annales Geophysicae ◽

10.5194/angeo-23-2897-2005 ◽

2005 ◽

Vol 23 (8) ◽

pp. 2897-2901 ◽

Cited By ~ 4

Author(s):

C. J. Xiao ◽

Z. Y. Pu ◽

Y. Wei ◽

Z. X. Liu ◽

C. M. Carr ◽

...

Keyword(s):

Flux Rope ◽

Detailed Comparison ◽

Dominant Negative ◽

Time Interval ◽

Low Latitude ◽

Guide Field ◽

Flux Ropes ◽

The Mean ◽

Mean Time ◽

Made In

Abstract. From 23:10 to 23:50 UT on 18 March 2004, the Double Star TC-1 spacecraft detected eight flux ropes at the outbound crossing of the southern dawnside magnetopause. A notable guide field existed inside all ropes. In the mean time the Cluster spacecraft were staying in the magnetosheath and found that the events occurred under the condition of southward IMF Bz and dominant negative IMF By. There are six ropes that appeared quasi-periodically, with a repeated period being approximately 1-4 min. The last flux rope lasts for a longer time interval with a larger peak in the BN variations; it can thus be referred to as a typical FTE. The 18 March 2004 event is quite similar to the multiple flux rope event observed by Cluster on 26 January 2001 at the northern duskside high-latitude magnetopause. A detailed comparison of these two events is made in the paper. Preliminary studies imply that both of these multiple flux ropes events seem to be produced by component reconnection at the dayside low-latitude magnetopause.

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Statistical Relationship between Interplanetary Magnetic Field Conditions and the Helicity Sign of Flux Transfer Event Flux Ropes

10.1002/essoar.10504554.1 ◽

2020 ◽

Author(s):

Rungployphan Kieokaew ◽

B Lavraud ◽

N Fargette ◽

A Marchaudon ◽

V Génot ◽

...

Keyword(s):

Magnetic Field ◽

Interplanetary Magnetic Field ◽

Field Conditions ◽

Statistical Relationship ◽

Transfer Event ◽

Flux Ropes ◽

Flux Transfer

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Flux transfer event observation at Saturn's dayside magnetopause by the Cassini spacecraft

Geophysical Research Letters ◽

10.1002/2016gl069260 ◽

2016 ◽

Vol 43 (13) ◽

pp. 6713-6723 ◽

Cited By ~ 22

Author(s):

Jamie M. Jasinski ◽

James A. Slavin ◽

Christopher S. Arridge ◽

Gangkai Poh ◽

Xianzhe Jia ◽

...

Keyword(s):

Transfer Event ◽

Dayside Magnetopause ◽

Flux Transfer ◽

Cassini Spacecraft

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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.

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The structure of flux transfer events recovered from Cluster data

Annales Geophysicae ◽

10.5194/angeo-24-603-2006 ◽

2006 ◽

Vol 24 (2) ◽

pp. 603-618 ◽

Cited By ~ 79

Author(s):

H. Hasegawa ◽

B. U. Ö. Sonnerup ◽

C. J. Owen ◽

B. Klecker ◽

G. Paschmann ◽

...

Keyword(s):

Magnetic Field ◽

Magnetic Flux ◽

Flux Rope ◽

Time Interval ◽

Reconstruction Technique ◽

Magnetic Flux Ropes ◽

Flux Transfer Events ◽

Cluster Data ◽

Flux Ropes ◽

Flux Transfer

Abstract. The structure and formation mechanism of a total of five Flux Transfer Events (FTEs), encountered on the equatorward side of the northern cusp by the Cluster spacecraft, with separation of ~5000 km, are studied by applying the Grad-Shafranov (GS) reconstruction technique to the events. The technique generates a magnetic field/plasma map of the FTE cross section, using combined magnetic field and plasma data from all four spacecraft, under the assumption that the structure is two-dimensional (2-D) and time-independent. The reconstructed FTEs consist of one or more magnetic flux ropes embedded in the magnetopause, suggesting that multiple X-line reconnection was involved in generating the observed FTEs. The dimension of the flux ropes in the direction normal to the magnetopause ranges from about 2000 km to more than 1 RE. The orientation of the flux rope axis can be determined through optimization of the GS map, the result being consistent with those from various single-spacecraft methods. Thanks to this, the unambiguous presence of a strong core field is confirmed, providing evidence for component merging. The amount of magnetic flux contained within each flux rope is calculated from the map and, by dividing it by the time interval between the preceding FTE and the one reconstructed, a lower limit of the reconnection electric field during the creation of the flux rope can be estimated; the estimated value ranges from ~0.11 to ~0.26 mV m-1, with an average of 0.19 mV m-1. This can be translated to the reconnection rate of 0.038 to 0.074, with an average of 0.056. Based on the success of the 2-D model in recovering the observed FTEs, the length of the X-lines is estimated to be at least a few RE.

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Patchy Reconnection and Magnetic Ropes in Astrophysical Plasmas

Symposium - International Astronomical Union ◽

10.1017/s0074180900075483 ◽

1985 ◽

Vol 107 ◽

pp. 25-42

Author(s):

C. T. Russell

Keyword(s):

Magnetic Structure ◽

Velocity Shear ◽

Astrophysical Plasmas ◽

Transfer Event ◽

Simple Geometry ◽

Flux Ropes ◽

Flux Transfer ◽

Twisted Tubes ◽

Kink Instability

Reconnection is clearly observed at the terrestrial magnetopause but seldom in the simple geometry originally proposed. Most often reconnection is patchy, forming tubes of twisted flux. The passage of one of these twisted tubes has been called a flux transfer event. Similar twisted tubes, or flux ropes, are formed at Venus by velocity shear. These tubes become so highly twisted that they become kink unstable. The presence of the kink instability suggests a way of creating compound flux ropes as have been postulated to be necessary to explain photospheric magnetic structure.

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Observations of an Electron-only Magnetic Reconnection within a macroscopic Flux Rope in the Magnetotail

10.5194/egusphere-egu2020-2841 ◽

2020 ◽

Author(s):

Hengyan Man ◽

Meng Zhou ◽

Yongyuan Yi ◽

Zhihong Zhong ◽

Xiaohua Deng

Keyword(s):

Electric Field ◽

Magnetic Reconnection ◽

Current Sheet ◽

Large Scale ◽

Energy Transport ◽

Flux Rope ◽

Space Plasmas ◽

Positive Energy ◽

Guide Field ◽

Flux Ropes

It is widely accepted that flux ropes play important roles in the momentum and energy transport in space plasmas. Recent observations found that magnetic reconnection occurs at the interface between two counter flows around the center of flux ropes. In this presentation, we report a novel observation by MMS that reconnection occurs at the edge of a large-scale flux rope, the cross-section of which was about 2.5 Re. The flux rope was observed at the dusk side in Earth&#8217;s magnetotail and was highly oblique with its axis proximity along the XGSM direction. We found an electron-scale current sheet near the edge of this flux rope. The Hall magnetic and electric field, super-Alfv&#233;nic electron outflow, parallel electric field and positive energy dissipation were observed associated with the current sheet. All the above signatures indicate that MMS detected a reconnecting current sheet in the presence of a large guide field. Interestingly, ions were not coupled in this reconnection, akin to the electron-only reconnection observed in the magnetosheath turbulence. We suggest that the electron-scale current sheet was caused by the strong magnetic field perturbation inside the flux rope. This result will shed new lights for understanding the multi-scale coupling associated with flux ropes in space plasmas.

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