WKB estimates for the onset of ideal MHD instabilities in solar coronal loops

Solar Physics ◽  
1994 ◽  
Vol 150 (1-2) ◽  
pp. 99-115 ◽  
Author(s):  
A. W. Hood ◽  
P. De Bruyne ◽  
R. A. M. Van Der Linden ◽  
M. Goossens
Keyword(s):  
Coronal Loops ◽  
Mhd Instabilities ◽  
Ideal Mhd ◽  
Solar Coronal

scholarly journals Can Multi-threaded Flux Tubes in Coronal Arcades Support a Magnetohydrodynamic Avalanche?

Solar Physics ◽  
2021 ◽  
Vol 296 (8) ◽  
Author(s):  
J. Threlfall ◽  
J. Reid ◽  
A. W. Hood
Keyword(s):  
Magnetic Fields ◽  
Three Dimensional ◽  
Coronal Loops ◽  
Flux Tubes ◽  
Single Thread ◽  
Mhd Instabilities ◽  
Mhd Instability ◽  
Mhd Simulations ◽  
Ideal Mhd ◽  
Model Geometry

AbstractMagnetohydrodynamic (MHD) instabilities allow energy to be released from stressed magnetic fields, commonly modelled in cylindrical flux tubes linking parallel planes, but, more recently, also in curved arcades containing flux tubes with both footpoints in the same photospheric plane. Uncurved cylindrical flux tubes containing multiple individual threads have been shown to be capable of sustaining an MHD avalanche, whereby a single unstable thread can destabilise many. We examine the properties of multi-threaded coronal loops, wherein each thread is created by photospheric driving in a realistic, curved coronal arcade structure (with both footpoints of each thread in the same plane). We use three-dimensional MHD simulations to study the evolution of single- and multi-threaded coronal loops, which become unstable and reconnect, while varying the driving velocity of individual threads. Experiments containing a single thread destabilise in a manner indicative of an ideal MHD instability and consistent with previous examples in the literature. The introduction of additional threads modifies this picture, with aspects of the model geometry and relative driving speeds of individual threads affecting the ability of any thread to destabilise others. In both single- and multi-threaded cases, continuous driving of the remnants of disrupted threads produces secondary, aperiodic bursts of energetic release.

Propagation of electron beams in solar coronal loops

2001 ◽  
Vol 7 (2s) ◽  
pp. 93-95
Author(s):  
V.N. Melnik ◽  
Keyword(s):  
Electron Beams ◽  
Coronal Loops ◽  
Solar Coronal

scholarly journals Dynamics of solar coronal loops

2003 ◽  
Vol 411 (3) ◽  
pp. 605-613 ◽  
Author(s):  
D. A. N. Müller ◽  
V. H. Hansteen ◽  
H. Peter
Keyword(s):  
Coronal Loops ◽  
Solar Coronal

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

2010 ◽  
Vol 723 (2) ◽  
pp. 1180-1187 ◽  
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

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

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.

Repeated Coronal Condensations Caused by Magnetic Reconnection between Solar Coronal Loops

2019 ◽  
Vol 884 (1) ◽  
pp. 34 ◽  
Author(s):  
Leping Li ◽  
Hardi Peter ◽  
Lakshmi Pradeep Chitta ◽  
Jun Zhang ◽  
Jiangtao Su ◽  
...  
Keyword(s):  
Magnetic Reconnection ◽  
Coronal Loops ◽  
Solar Coronal
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