Measuring the magnetic field of a trans-equatorial loop system using coronal seismology

Context. EIT waves are freely-propagating global pulses in the low corona which are strongly associated with the initial evolution of coronal mass ejections (CMEs). They are thought to be large-Amplitude, fast-mode magnetohydrodynamic waves initially driven by the rapid expansion of a CME in the low...

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Autores principales: Long, D.M., Valori, G., Pérez-Suárez, D., Morton, R.J., Vásquez, A.M.
Formato: JOUR
Materias:
Sun: corona
Sun: magnetic fields
Sun: oscillations
Astrophysics
Extrapolation
Magnetohydrodynamics
Seismology
Shear waves
Solar system
Wave propagation
Empirical Mode Decomposition
Magnetic field extrapolations
Magnetohydrodynamic waves
Solar dynamics observatories
Sun : corona
Sun: magnetic field
Transverse wave propagation
Magnetic field measurement
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00046361_v603_n_p_Long
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_00046361_v603_n_p_Long2023-10-03T14:01:11Z Measuring the magnetic field of a trans-equatorial loop system using coronal seismology Long, D.M. Valori, G. Pérez-Suárez, D. Morton, R.J. Vásquez, A.M. Sun: corona Sun: magnetic fields Sun: oscillations Astrophysics Extrapolation Magnetohydrodynamics Seismology Shear waves Solar system Wave propagation Empirical Mode Decomposition Magnetic field extrapolations Magnetohydrodynamic waves Solar dynamics observatories Sun : corona Sun: magnetic field Sun: oscillations Transverse wave propagation Magnetic field measurement Context. EIT waves are freely-propagating global pulses in the low corona which are strongly associated with the initial evolution of coronal mass ejections (CMEs). They are thought to be large-Amplitude, fast-mode magnetohydrodynamic waves initially driven by the rapid expansion of a CME in the low corona. Aims. An EIT wave was observed on 6 July 2012 to impact an adjacent trans-equatorial loop system which then exhibited a decaying oscillation as it returned to rest. Observations of the loop oscillations were used to estimate the magnetic field strength of the loop system by studying the decaying oscillation of the loop, measuring the propagation of ubiquitous transverse waves in the loop and extrapolating the magnetic field from observed magnetograms. Methods. Observations from the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory (SDO/AIA) and the Coronal Multi-channel Polarimeter (CoMP) were used to study the event. An Empirical Mode Decomposition analysis was used to characterise the oscillation of the loop system in CoMP Doppler velocity and line width and in AIA intensity. Results. The loop system was shown to oscillate in the 2nd harmonic mode rather than at the fundamental frequency, with the seismological analysis returning an estimated magnetic field strength of 5.5 ± 1.5 G. This compares to the magnetic field strength estimates of 1-9 G and 3-9 G found using the measurements of transverse wave propagation and magnetic field extrapolation respectively. © ESO, 2017. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00046361_v603_n_p_Long
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Sun: corona
Sun: magnetic fields
Sun: oscillations
Astrophysics
Extrapolation
Magnetohydrodynamics
Seismology
Shear waves
Solar system
Wave propagation
Empirical Mode Decomposition
Magnetic field extrapolations
Magnetohydrodynamic waves
Solar dynamics observatories
Sun : corona
Sun: magnetic field
Sun: oscillations
Transverse wave propagation
Magnetic field measurement
spellingShingle Sun: corona
Sun: magnetic fields
Sun: oscillations
Astrophysics
Extrapolation
Magnetohydrodynamics
Seismology
Shear waves
Solar system
Wave propagation
Empirical Mode Decomposition
Magnetic field extrapolations
Magnetohydrodynamic waves
Solar dynamics observatories
Sun : corona
Sun: magnetic field
Sun: oscillations
Transverse wave propagation
Magnetic field measurement
Long, D.M.
Valori, G.
Pérez-Suárez, D.
Morton, R.J.
Vásquez, A.M.
Measuring the magnetic field of a trans-equatorial loop system using coronal seismology
topic_facet Sun: corona
Sun: magnetic fields
Sun: oscillations
Astrophysics
Extrapolation
Magnetohydrodynamics
Seismology
Shear waves
Solar system
Wave propagation
Empirical Mode Decomposition
Magnetic field extrapolations
Magnetohydrodynamic waves
Solar dynamics observatories
Sun : corona
Sun: magnetic field
Sun: oscillations
Transverse wave propagation
Magnetic field measurement
description Context. EIT waves are freely-propagating global pulses in the low corona which are strongly associated with the initial evolution of coronal mass ejections (CMEs). They are thought to be large-Amplitude, fast-mode magnetohydrodynamic waves initially driven by the rapid expansion of a CME in the low corona. Aims. An EIT wave was observed on 6 July 2012 to impact an adjacent trans-equatorial loop system which then exhibited a decaying oscillation as it returned to rest. Observations of the loop oscillations were used to estimate the magnetic field strength of the loop system by studying the decaying oscillation of the loop, measuring the propagation of ubiquitous transverse waves in the loop and extrapolating the magnetic field from observed magnetograms. Methods. Observations from the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory (SDO/AIA) and the Coronal Multi-channel Polarimeter (CoMP) were used to study the event. An Empirical Mode Decomposition analysis was used to characterise the oscillation of the loop system in CoMP Doppler velocity and line width and in AIA intensity. Results. The loop system was shown to oscillate in the 2nd harmonic mode rather than at the fundamental frequency, with the seismological analysis returning an estimated magnetic field strength of 5.5 ± 1.5 G. This compares to the magnetic field strength estimates of 1-9 G and 3-9 G found using the measurements of transverse wave propagation and magnetic field extrapolation respectively. © ESO, 2017.
format JOUR
author Long, D.M.
Valori, G.
Pérez-Suárez, D.
Morton, R.J.
Vásquez, A.M.
author_facet Long, D.M.
Valori, G.
Pérez-Suárez, D.
Morton, R.J.
Vásquez, A.M.
author_sort Long, D.M.
title Measuring the magnetic field of a trans-equatorial loop system using coronal seismology
title_short Measuring the magnetic field of a trans-equatorial loop system using coronal seismology
title_full Measuring the magnetic field of a trans-equatorial loop system using coronal seismology
title_fullStr Measuring the magnetic field of a trans-equatorial loop system using coronal seismology
title_full_unstemmed Measuring the magnetic field of a trans-equatorial loop system using coronal seismology
title_sort measuring the magnetic field of a trans-equatorial loop system using coronal seismology
url http://hdl.handle.net/20.500.12110/paper_00046361_v603_n_p_Long
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AT mortonrj measuringthemagneticfieldofatransequatorialloopsystemusingcoronalseismology
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