Short-Period Waves That Heat the Corona Detected at the 1999 Eclipse
Jay M. Pasachoff,Jay M. Pasachoff,Bryce A. Babcock,Kevin D. Russell,Daniel B. Seaton,Daniel B. Seaton +5 more
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In this article, the authors used Fourier analysis to search in the [Fe xiv] channel for intensity oscillations in loops at the base of the corona and concluded that MHD waves remain a viable method for coronal heating.Abstract:
As a part of a study of the cause of solar coronal heating, we searched for high-frequency (∼ 1 Hz) intensity oscillations in coronal loops in the [Fe xiv] coronal green line. We summarize results from observations made at the 11 August 1999 total solar eclipse from Râmnicu-Vâlcea, Romania, through clear skies. We discuss the image reduction and analysis through two simultaneous series of coronal CCD images digitized at 10 Hz for a total time of about 140 s. One series of images was taken through a 3.6 A filter isolating the 5303 A[Fe xiv] coronal green line and the other through a 100 A filter in the nearby K-corona continuum. Previous observations, described in Pasachoff et al. (2000), showed no evidence for oscillations in the [Fe xiv] green line at a level greater than 2% of coronal intensity. We describe several improvements made over the 1998 eclipse that led to increased image clarity and sensitivity. The corona was brighter in 1999 with the solar maximum, further improving the data. We use Fourier analysis to search in the [Fe xiv] channel for intensity oscillations in loops at the base of the corona. Such oscillations in the 1-Hz range are predicted as a result of density fluctuations from the resonant absorption of MHD waves. The dissipation of a significant amount of mechanical energy from the photosphere into the corona through this mechanism could provide sufficient energy to heat the corona. A Monte Carlo model of the data suggests the presence of enhanced power, particularly in the 0.75–1.0 Hz range, and we conclude that MHD waves remain a viable method for coronal heating.read more
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Journal ArticleDOI
Alfven waves in the solar corona.
Steven Tomczyk,Scott W. McIntosh,Stephen L. Keil,Philip G. Judge,Thomas A. Schad,D. H. Seeley,J. Edmondson +6 more
TL;DR: In this paper, the authors reported the detection of Alfven waves in intensity, line-of-sight velocity, and linear polarization images of the solar corona taken using the FeXIII 1074.7-nanometer coronal emission line with the Coronal Multi-Channel Polarimeter (CoMP) instrument at the National Solar Observatory, New Mexico.
Alfven Waves in the Solar Corona
Steven Tomczyk,Scott W. McIntosh,Stephen L. Keil,Philip G. Judge,Thomas A. Schad,D. H. Seeley,J. Edmondson +6 more
TL;DR: An estimate of the energy carried by the waves that are spatially resolved indicates that they are too weak to heat the solar corona; however, unresolved Alfvén waves may carry sufficient energy.
Journal ArticleDOI
Eclipse observations of high-frequency oscillations in active region coronal loops
A. C. Katsiyannis,David R. Williams,David R. Williams,R. T. J. McAteer,Peter T. Gallagher,Peter T. Gallagher,Francis P. Keenan,Fionn Murtagh,Fionn Murtagh +8 more
TL;DR: In this paper, a wavelet analysis was used to identify twenty 4 × 4 arcsec 2 areas showing intensity oscillations in the frequency range 0.15-0.25 Hz (7-4 s) and last for at least three periods at a confidence level of more than 99% and arise just outside known coronal loops.
Journal ArticleDOI
Turbulence in the Solar Atmosphere and Solar Wind
Arakel Petrosyan,André Balogh,André Balogh,M. L. Goldstein,J. Léorat,E. Marsch,Kristof Petrovay,Kristof Petrovay,B. Roberts,R. von Steiger,Jean-Claude Vial +10 more
TL;DR: In this paper, a review article is presented to critically analyze turbulence and its role in the solar atmosphere and solar wind, as well as to provide a tutorial overview of topics worth clarification.
Journal ArticleDOI
Eclipse observations of high-frequency oscillations in active region coronal loops
A. C. Katsiyannis,David R. Williams,David R. Williams,R. T. J. McAteer,Peter T. Gallagher,Peter T. Gallagher,Francis P. Keenan,Fionn Murtagh,Fionn Murtagh +8 more
TL;DR: In this article, a wavelet analysis was used to identify twenty 4x4 arcsec2 areas showing intensity oscillations in the corona during the 1999 total solar eclipse. All detections lie in the frequency Hz (5-3 s), last for at least 3 periods at a confidence level of more than 99% and arise just outside known coronal loops, leading them to suggest that they occur in low emission-measure or different temperature loops associated with the active region.
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