Repeated Coronal Condensations Caused by Magnetic Reconnection between Solar Coronal Loops

Context. Coronal rain consists of cool plasma condensations formed in coronal loops as a result of thermal instability. The standard models of coronal rain formation assume that the heating is quasi-steady and localised at the coronal loop footpoints. Aims. We present an observation of magnetic reconnection in the corona and the associated impulsive heating triggering formation of coronal rain condensations. Methods. We analyse combined SDO/AIA and IRIS observations of a coronal rain event following a reconnection between threads of a low-lying prominence flux rope and surrounding coronal field lines. Results. The reconnection of the twisted flux rope and open field lines leads to a release of magnetic twist. Evolution of the emission of one of the coronal loops involved in the reconnection process in different AIA bandpasses suggests that the loop becomes thermally unstable and is subject to the formation of coronal rain condensations following the reconnection and that the associated heating is localised in the upper part of the loop leg. Conclusions. In addition to the standard models of thermally unstable coronal loops with heating localised exclusively in the footpoints, thermal instability and subsequent formation of condensations can be triggered by the impulsive heating associated with magnetic reconnection occurring anywhere along a magnetic field line.

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MULTI-STRANDED AND MULTI-THERMAL SOLAR CORONAL LOOPS: EVIDENCE FROMHINODEX-RAY TELESCOPE AND EUV IMAGING SPECTROMETER DATA

The Astrophysical Journal ◽

10.1088/0004-637x/723/2/1180 ◽

2010 ◽

Vol 723 (2) ◽

pp. 1180-1187 ◽

Cited By ~ 30

Author(s):

J. T. Schmelz ◽

S. H. Saar ◽

K. Nasraoui ◽

V. L. Kashyap ◽

M. A. Weber ◽

...

Keyword(s):

Coronal Loops ◽

Imaging Spectrometer ◽

Spectrometer Data ◽

Euv Imaging ◽

Solar Coronal

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COMPARISON OF EXTREME ULTRAVIOLET IMAGING SPECTROMETER OBSERVATIONS OF SOLAR CORONAL LOOPS WITH ALFVÉN WAVE TURBULENCE MODELS

The Astrophysical Journal ◽

10.1088/0004-637x/786/1/28 ◽

2014 ◽

Vol 786 (1) ◽

pp. 28 ◽

Cited By ~ 21

Author(s):

M. Asgari-Targhi ◽

A. A. van Ballegooijen ◽

S. Imada

Keyword(s):

Extreme Ultraviolet ◽

Turbulence Models ◽

Alfven Wave ◽

Wave Turbulence ◽

Coronal Loops ◽

Imaging Spectrometer ◽

Solar Coronal

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Concerning the Dynamics of Energetic Protons in Coronal Magnetic Loops: Dispersion Effects of Alfven Waves

Symposium - International Astronomical Union ◽

10.1017/s007418090007618x ◽

1985 ◽

Vol 107 ◽

pp. 559-559

Author(s):

V. A. Mazur ◽

A. V. Stepanov

Keyword(s):

Magnetic Field ◽

Wave Dispersion ◽

Alfven Waves ◽

Alfven Wave ◽

Wave Number ◽

Alfvén Waves ◽

Coronal Loops ◽

Coronal Magnetic Loops ◽

The Magnetic Field ◽

Solar Coronal

It is shown that the existence of plasma density inhomogeneities (ducts) elongated along the magnetic field in coronal loops, and of Alfven wave dispersion, associated with the taking into account of gyrotropy U ≡ ω/ωi ≪ 1 (Leonovich et al., 1983), leads to the possibility of a quasi-longitudinal k⊥ < √U k‖ propagation (wave guiding) of Alfven waves. Here ω is the frequency of Alfven waves, ωi is the proton gyrofrequency, and k is the wave number. It is found that with the parameter ξ = ω2 R/ωi A > 1, where R is the inhomogeneity scale of a loop across the magnetic field, and A is the Alfven wave velocity, refraction of Alfven waves does not lead, as contrasted to Wentzel's inference (1976), to the waves going out of the regime of quasi-longitudinal propagation. As the result, the amplification of Alfven waves in solar coronal loops can be important. A study is made of the cyclotron instability of Alfven waves under solar coronal conditions.

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