Oscillation of Current Sheets in the Wake of a Flux Rope Eruption Observed by the Solar Dynamics Observatory

Aims. We aim to study a high-resolution observation of an asymmetric inflow magnetic reconnection between a filament and its surrounding magnetic loops in active region NOAA 12436 on 2015 October 23. Methods. We analyzed the multiband observations of the magnetic reconnection obtained by the New Vacuum Solar Telescope (NVST) and the Solar Dynamic Observatory. We calculated the NVST Hα Dopplergrams to determine the Doppler properties of the magnetic reconnection region and the rotation of a jet. Results. The filament firstly becomes active and then approaches its southwestern surrounding magnetic loops (L1) with a velocity of 9.0 km s−1. During this period, the threads of the filament become loose in the reconnection region and then reconnect with L1 in turn. L1 is pressed backward by the filament with a velocity of 5.5 km s−1, and then the magnetic reconnection occurs between them. A set of newly formed loops are separated from the reconnection site with a mean velocity of 127.3 km s−1. In the middle stage, some threads of the filament return back first with a velocity of 20.1 km s−1, and others return with a velocity of 4.1 km s−1 after about 07:46 UT. Then, L1 also begins to return with a velocity of 3.5 km s−1 at about 07:47 UT. At the same time, magnetic reconnection continues to occur between them until 07:51 UT. During the reconnection, a linear typical current sheet forms with a length of 5.5 Mm and a width of 1.0 Mm, and a lot of hot plasma blobs are observed propagating from the typical current sheet. During the reconnection, the plasma in the reconnection region and the typical current sheet always shows redshifted feature. Furthermore, the material and twist of the filament are injected into the newly longer-formed magnetic loops by the magnetic reconnection, which leads to the formation of a jet, and its rotation. Conclusions. The observational evidence for the asymmetric inflow magnetic reconnection is investigated. We conclude that the magnetic reconnection does occur in this event and results in the disconnection of the filament. The looseness of the filament may be due to the pressure imbalance between the inside and outside of the filament. The redshifted feature in the reconnection site can be explained by the expansion of the right flank of the filament to the lower atmosphere because of the complex magnetic configuration in this active region.

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“…In previous studies, multiple current sheet structures were discovered during one erupting event (e.g. Li et al 2016b).…”

Section: Resultsmentioning

confidence: 99%

A solar filament disconnected by magnetic reconnection

Xue

Yan

Yang

et al. 2020

A&A

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“…Another frequently used approach for measurements of the coronal magnetic field is coronal seismology or magnetoseismology, which refers to magnetic field diagnostics based on observations of MHD waves or oscillations (e.g., [34]). For transverse kink oscillations, the magnetic field strengths in or outside oscillating structures could be derived if the local density is assumed or estimated [35][36][37][38][39][40][41][42]. However, these rare single-oscillation events are often related to flares or CMEs, and their observations can provide an estimate of only the average field strength or one-dimensional (1D) distribution of field strength along an oscillating structure.…”

Section: Introductionmentioning

confidence: 99%

Mapping the magnetic field in the solar corona through magnetoseismology

Yang

Tomczyk

Morton

et al. 2020

Sci. China Technol. Sci.

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of magnetic field diagnostics based on observations of magnetohydrodynamic (MHD) waves, has been widely used to estimate the field strengths of oscillating structures in the solar corona. However, previously magnetoseismology was mostly applied to occasionally occurring oscillation events, providing an estimate of only the average field strength or one-dimensional distribution of field strength along an oscillating structure. This restriction could be eliminated if we apply magnetoseismology to the pervasive propagating transverse MHD waves discovered with the Coronal Multi-channel Polarimeter (CoMP). Using several CoMP observations of the Fe xiii 1074.7 nm and 1079.8 nm spectral lines, we obtained maps of the plasma density and wave phase speed in the corona, which allow us to map both the strength and direction of the coronal magnetic field in the plane of sky. We also examined distributions of the electron density and magnetic field strength, and compared their variations with height in the quiet Sun and active regions. Such measurements could provide critical information to advance our understanding of the Sun's magnetism and the magnetic coupling of the whole solar atmosphere.

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“…With the introduction of the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO), many of these plasma sheets have been observed with the 131Å channel (e.g. Reeves & Golub 2011;Warren et al 2011;Savage et al 2012;Liu et al 2013;Hanneman & Reeves 2014;Innes et al 2014;Gou et al 2015;Guidoni et al 2015;Li et al 2016), which is sensitive to plasma at about 10 MK (Boerner et al 2012). …”

Section: Introductionmentioning

confidence: 99%

An Exploration of Heating Mechanisms in a Supra-arcade Plasma Sheet Formed after a Coronal Mass Ejection

Reeves¹,

Freed²,

McKenzie³

et al. 2017

ApJ

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We perform a detailed analysis of the thermal structure of the region above the post-eruption arcade for a flare that occurred on 2011 October 22. During this event, a sheet of hot plasma is visible above the flare loops in the 131Å bandpass of the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO). Supra-arcade downflows (SADs) are observed traveling sunward through the post-eruption plasma sheet. We calculate differential emission measures using the AIA data and derive an emission measure weighted average temperature in the supra-arcade region. In areas where many SADs occur, the temperature of the supra-arcade plasma tends to increase, while in areas where no SADs are observed, the temperature tends to decrease. We calculate the plane-of-sky velocities in the supra-arcade plasma and use them to calculate the potential heating due to adiabatic compression and viscous heating. Ten of the 13 SADs studied have noticeable signatures in both the adiabatic and the viscous terms. The adiabatic heating due to compression of plasma in front of the SADs is on the order of 0.1 -0.2 MK/s, which is similar in magnitude to the estimated conductive cooling rate. This result supports the notion that SADs contribute locally to the heating of plasma in the supra-arcade region. We also find that in the region without SADs, the plasma cools at a rate slower than the estimated conductive cooling, indicating additional heating mechanisms may act globally to keep the plasma temperature high.

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Oscillation of Current Sheets in the Wake of a Flux Rope Eruption Observed by the Solar Dynamics Observatory

Cited by 55 publications

References 46 publications

A solar filament disconnected by magnetic reconnection

A solar filament disconnected by magnetic reconnection

Mapping the magnetic field in the solar corona through magnetoseismology

An Exploration of Heating Mechanisms in a Supra-arcade Plasma Sheet Formed after a Coronal Mass Ejection

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