Comparison of extreme ultraviolet imaging spectrometer observations of solar coronal loops with Alfvén wave turbulence models

Journal Article · Thu May 01 04:00:00 EDT 2014 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/786/1/28· OSTI ID:22356443

Asgari-Targhi, M.; Van Ballegooijen, A. A. ^[1]; Imada, S. ^[2]

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1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street MS-15, Cambridge, MA 02138 (United States)
2. Solar-Terrestrial Environment Laboratory, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601 (Japan)

The observed non-thermal widths of coronal emission lines could be due to Alfvén wave turbulence. To test this idea, we examine and analyze the dynamics of an active region observed on 2012 September 7. We use spectral line profiles of Fe XII, Fe XIII, Fe XV, and Fe XVI obtained by the Extreme-ultraviolet Imaging Spectrometer on the it Hinode spacecraft. The observations show non-thermal velocities, Doppler outflows, and intensities for loops in this active region. The observed non-thermal velocities are compared with predictions from models for Alfvén wave turbulence in the observed coronal loops. This modeling takes into account the relationship between the width of the coronal emission lines and the orientation of the coronal loops with respect to the line-of-sight direction. We find that in order to produce the observed line widths we need to introduce a random parallel-flow component in addition to the perpendicular velocity due to Alfvén waves. The observed widths are consistent with photospheric footpoint velocities in the range 0.3-1.5 km s{sup –1}. We conclude that the Alfvén wave turbulence model is a strong candidate for explaining how the observed loops are heated.

• OSTI ID: 22356443
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 786; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ALFVEN WAVES
COMPARATIVE EVALUATIONS
DOPPLER EFFECT
EMISSION
EXTREME ULTRAVIOLET RADIATION
FORECASTING
IRON
LINE WIDTHS
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
SIMULATION
SOLAR CORONA
SPECTRA
SPECTROMETERS
SUN
TURBULENCE
VELOCITY