The Kinematics of a Globally Propagating Disturbance in the Solar Corona

By D. Long, P. Gallagher, R. McAteer, D. S. Bloomfield. 2008

140 citations recorded by the source corpus.

The kinematics of a globally propagating disturbance (also known as an “EIT wave”) is discussed using Extreme UltraViolet Imager (EUVI) data from the Solar Terrestrial Relations Observatory (STEREO). We show for the first time that an impulsively generated propagating disturbance has similar kinematics in all four EUVI passbands (304, 171, 195, and 284 Å). In the 304 Å passband the disturbance shows a velocity peak of 238 ± 20 km s−1 within ~28 minutes of its launch, varying in acceleration from 76 to –102 m s−2. This passband contains a strong contribution from a Si XI line (303.32 Å) with a peak formation temperature of ~1.6 MK. The 304 Å emission may therefore be coronal rather than chromospheric in origin. Comparable velocities and accelerations are found in the coronal 195 Å passband, while lower values are found in the lower cadence 284 Å passband. In the higher cadence 171 Å passband the velocity varies significantly, peaking at 475 ± 47 km s−1 within ~20 minutes of launch, with a variation in acceleration from 816 to –413 m s−2. The high image cadence of the 171 Å passband (2.5 minutes compared to 10 minutes for the similar temperature response 195 Å passband) is found to have a major effect on the measured velocity and acceleration of the pulse, which increase by factors of ~2 and ~10, respectively. This implies that previously measured values (e.g., using EIT) may have been underestimated. We also note that the disturbance shows strong reflection from a coronal hole in both the 171 and 195 Å passbands. The observations are consistent with an impulsively generated fast-mode magnetoacoustic wave.

Subfields: Astronomy and Astrophysics, Molecular Biology

View Paper: https://www.semanticscholar.org/paper/4a154a32824c567de10913107b72a0063ce4b0e1

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In Astronomy and Astrophysics

1. Nat Gopalswamy
2. M. Temmer
3. S. Yashiro
4. R. Howard
5. S. Freeland
6. J. C. Raymond
7. W. Thompson
8. P. Grigis

In Molecular Biology

1. Nat Gopalswamy
2. S. Yashiro
3. M. Temmer
4. R. Howard
5. J. C. Raymond
6. A. Thernisien
7. A. Vourlidas
8. D. Webb

Citations in the corpus

• Advances in Observing Various Coronal EUV Waves in the SDO Era and Their Seismological Applications (Invited Review) (2014, unknown): “Observational case studies with three generations of EUV imagers have found many EIT waves of nearly constant speeds (e.g. Ma et al., 2009; Liu et al., 2010) and many others with decelerations (e.g. Warmuth et al., 2004; Long et al., 2008; Zhao et al., 2011; Xue et al., 2013).”
• EUV WAVE REFLECTION FROM A CORONAL HOLE (2009, background): “Long et al. (2008) measured the speed of the direct wave at a position angle of of 270◦ and found an average speed of ∼430km/s, consistent with our meaurements shown in Fig.4.”
• OBSERVATIONS AND INTERPRETATION OF A LOW CORONAL SHOCK WAVE OBSERVED IN THE EUV BY THE SDO/AIA (2011, background): “…twin Solar–Terrestrial Relations Observatory (STEREO; Kaiser et al. 2008) spacecraft have advanced our understanding of the diffuse EUV wave (e.g., Long et al. 2008; Veronig et al. 2008; Gopalswamy et al. 2009; Attrill et al. 2009; Patsourakos et al. 2009; Ma et al. 2009; Kienreich et al. 2009;…”