UNRAVELLING THE COMPONENTS OF A MULTI-THERMAL CORONAL LOOP USING MAGNETOHYDRODYNAMIC SEISMOLOGY

ABSTRACT Coronal loops, constituting the basic building blocks of the active Sun, serve as primary targets to help understand the mechanisms responsible for maintaining multi-million Kelvin temperatures in the solar and stellar coronae. Despite significant advances in observations and theory, our kn...

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Bibliographic Details
Published in:The Astrophysical journal 2017-01, Vol.834 (2), p.103
Main Authors: Prasad, S. Krishna, Jess, D. B., Klimchuk, J. A., Banerjee, D.
Format: Article
Language:English
Subjects:
Astrophysics
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
Channels
Coronal loops
EXTRAPOLATION
Fluid flow
FORCE-FREE MAGNETIC FIELDS
HEATING
Magnetic fields
MAGNETOACOUSTIC WAVES
MAGNETOACOUSTICS
MAGNETOHYDRODYNAMICS
magnetohydrodynamics (MHD)
NONLINEAR PROBLEMS
OSCILLATIONS
SEISMOLOGY
STELLAR CORONAE
SUN
Sun: corona
Sun: fundamental parameters
Sun: oscillations
SUNSPOTS
Temperature
TEMPERATURE GRADIENTS
Temperature variations
VELOCITY
Wave propagation
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Summary:ABSTRACT Coronal loops, constituting the basic building blocks of the active Sun, serve as primary targets to help understand the mechanisms responsible for maintaining multi-million Kelvin temperatures in the solar and stellar coronae. Despite significant advances in observations and theory, our knowledge on the fundamental properties of these structures is limited. Here, we present unprecedented observations of accelerating slow magnetoacoustic waves along a coronal loop that show differential propagation speeds in two distinct temperature channels, revealing the multi-stranded and multithermal nature of the loop. Utilizing the observed speeds and employing nonlinear force-free magnetic field extrapolations, we derive the actual temperature variation along the loop in both channels, and thus are able to resolve two individual components of the multithermal loop for the first time. The obtained positive temperature gradients indicate uniform heating along the loop, rather than isolated footpoint heating.
ISSN:0004-637X
1538-4357
DOI:10.3847/1538-4357/834/2/103