scholarly journals Correlation of core field polarity of magnetotail flux ropes with the IMFBy: Reconnection guide field dependency

2014 ◽  
Vol 119 (4) ◽  
pp. 2933-2944 ◽  
Author(s):  
W.-L. Teh ◽  
R. Nakamura ◽  
H. Karimabadi ◽  
W. Baumjohann ◽  
T. L. Zhang
Keyword(s):  
Field Polarity ◽  
Field Dependency ◽  
Core Field ◽  
Guide Field ◽  
Flux Ropes

Double‐peaked core field of flux ropes during magnetic reconnection

2017 ◽  
Vol 122 (6) ◽  
pp. 6374-6384 ◽  
Author(s):  
Chaoxu Liu ◽  
Xueshang Feng ◽  
Rumi Nakamura ◽  
Jianpeng Guo ◽  
Rongsheng Wang
Keyword(s):  
Magnetic Reconnection ◽  
Core Field ◽  
Flux Ropes

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

2005 ◽  
Vol 23 (8) ◽  
pp. 2897-2901 ◽  
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.

scholarly journals Cluster observations of flux rope structures in the near-tail

2006 ◽  
Vol 24 (2) ◽  
pp. 651-666 ◽  
Author(s):  
P. D. Henderson ◽  
C. J. Owen ◽  
I. V. Alexeev ◽  
J. Slavin ◽  
A. N. Fazakerley ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Plasma Sheet ◽  
Lower Estimate ◽  
Flux Rope ◽  
Plasma Pressure ◽  
Magnetic Pressure ◽  
Total Force ◽  
Core Field ◽  
Flux Ropes ◽  
The Magnetic Field

Abstract. An investigation of the 2003 Cluster tail season has revealed small flux ropes in the near-tail plasma sheet of Earth. These flux ropes manifest themselves as a bipolar magnetic field signature (usually predominantly in the Z-component) associated with a strong transient peak in one or more of the other components (usually the Y-component). These signatures are interpreted as the passage of a cylindrical magnetic structure with a strong axial magnetic field over the spacecraft position. On the 2 October 2003 all four Cluster spacecraft observed a flux rope in the plasma sheet at X (GSM) ~-17 RE. The flux rope was travelling Earthward and duskward at ~160 kms-1, as determined from multi-spacecraft timing. This is consistent with the observed south-then-north bipolar BZ signature and corresponds to a size of ~0.3 RE (a lower estimate, measuring between the inflection points of the bipolar signature). The axis direction, determined from multi-spacecraft timing and the direction of the strong core field, was close to the intermediate variance direction of the magnetic field. The current inside the flux rope, determined from the curlometer technique, was predominantly parallel to the magnetic field. However, throughout the flux rope, but more significant in the outer sections, a non-zero component of current perpendicular to the magnetic field existed. This shows that the flux rope was not in a "constant α" force-free configuration, i.e. the magnetic force, J×B was also non-zero. In the variance frame of the magnetic field, the components of J×B suggest that the magnetic pressure force was acting to expand the flux rope, i.e. directed away from the centre of the flux rope, whereas the smaller magnetic tension force was acting to compress the flux rope. The plasma pressure is reduced inside the flux rope. A simple estimate of the total force acting on the flux rope from the magnetic forces and surrounding plasma suggests that the flux rope was experiencing an expansive total force. On 13 August 2003 all four Cluster spacecraft observed a flux rope at X (GSM) ~-18 RE. This flux rope was travelling tailward at 200 kms-1, consistent with the observed north-then-south bipolar BZ signature. The bipolar signature corresponds to a size of ~0.3 RE (lower estimate). In this case, the axis, determined from multi-spacecraft timing and the direction of the strong core field, was directed close to the maximum variance direction of the magnetic field. The current had components both parallel and perpendicular to the magnetic field, and J×B was again larger in the outer sections of the flux rope than in the centre. This flux rope was also under expansive magnetic pressure forces from J×B, i.e. directed away from the centre of the flux rope, and had a reduced plasma pressure inside the flux rope. A simple total force calculation suggests that this flux rope was experiencing a large expansive total force. The observations of a larger J×B signature in the outer sections of the flux ropes when compared to the centre may be explained if the flux ropes are observed at an intermediate stage of their evolution after creation by reconnection at multiple X lines near the Cluster apogee. It is suggested that these flux ropes are in the process of relaxing towards the force-free like configuration often observed further down the tail. The centre of the flux ropes may contain older reconnected flux at a later evolutionary stage and may therefore be more force-free.

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

2012 ◽  
Vol 117 (A7) ◽  
pp. n/a-n/a ◽  
Author(s):  
Rongsheng Wang ◽  
Rumi Nakamura ◽  
Quanming Lu ◽  
Aimin Du ◽  
Tielong Zhang ◽  
...  
Keyword(s):  
Magnetic Flux ◽  
Magnetic Reconnection ◽  
Current Sheet ◽  
Magnetic Flux Ropes ◽  
Guide Field ◽  
Flux Ropes

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

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

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

Observation of directional change of core field inside flux ropes within one reconnection diffusion region in the Earth’s magnetotail

2014 ◽  
Vol 59 (34) ◽  
pp. 4797-4803 ◽  
Author(s):  
Shiyong Huang ◽  
Ye Pang ◽  
Zhigang Yuan ◽  
Xiaohua Deng ◽  
Jiansen He ◽  
...  
Keyword(s):  
Diffusion Region ◽  
Core Field ◽  
Flux Ropes ◽  
Directional Change

MMS observations of oblique small-scale magnetopause flux ropes near the ion diffusion region during weak guide-field reconnection

2017 ◽  
Vol 44 (13) ◽  
pp. 6517-6524 ◽  
Author(s):  
W.-L. Teh ◽  
R. E. Denton ◽  
B. U. Ö. Sonnerup ◽  
C. Pollock
Keyword(s):  
Small Scale ◽  
Diffusion Region ◽  
Ion Diffusion ◽  
Guide Field ◽  
Flux Ropes

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

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

<p>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’s magnetotail and was highly oblique with its axis proximity along the X<sub>GSM</sub> direction. We found an electron-scale current sheet near the edge of this flux rope. The Hall magnetic and electric field, super-Alfvénic 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.</p>

scholarly journals A new method to identify flux ropes in space plasmas

2018 ◽  
Vol 36 (5) ◽  
pp. 1275-1283
Author(s):  
Shiyong Huang ◽  
Pufan Zhao ◽  
Jiansen He ◽  
Zhigang Yuan ◽  
Meng Zhou ◽  
...  
Keyword(s):  
Flux Rope ◽  
Target Function ◽  
Weighted Average ◽  
Correlation Coefficients ◽  
New Method ◽  
Space Plasmas ◽  
Core Field ◽  
Flux Ropes ◽  
The Ideal

Abstract. Flux ropes are frequently observed in the space plasmas, such as solar wind, planetary magnetosphere and magnetosheath etc., and play an important role in the reconnection process and mass and flux transportation. One usually uses bipolar signature and strong core field to identify the flux ropes. We propose here one new method to identify flux ropes based on the correlations between the variables of the data from in situ spacecraft observations and the “target function to be correlated” (TFC) from the ideal flux rope model. Through comparing the correlation coefficients of different variables at different times and scales, and performing weighted-average techniques, this method can derive the scales and locations of the flux ropes. We compare it with other methods and also discuss the limitation of our method.

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