Multi-temperature Analysis of a Sigmoidal Active Region
K.Hori1), L.K.Harra2), R.Moore, D.Falconer3)
1) Hiraiso Solar Observatory, National Institute of Information and Communications Technology, Isozaki 3601, Hitachinaka, Ibaraki 311-1202, Japan
Using the Coronal Diagnostic Spectrometer (CDS) on SOHO spacecraft, we observed the temporal evolution of an active region NOAA #9254 from December 6 to 9, 2000. Within an field-of-view of 122" x 121" (89000 km), the CDS observed the AR9254 with a time resolution of 30 minutes in 10 spectral lines; Fe XVI 360.76A (2.5MK), Si XII 520.66A (1.8MK), Mg X 624.94A (1.1MK), Mg IX 367.93A (1.0MK), Ca X 557.98A (0.7MK), Ne VI 562.83A (0.4MK), O V 629.39A (0.2MK), O III 599.59A (0.1MK), He II 607.71A, and He I 584.33A, which can see dynamics in different layers of the solar atmosphere from the chromosphere through to the corona. Although the AR9254 did not produce a flare during the CDS observation period, the CDS raster images show formation and decay of a sigmoidal (S-shaped) structure in a high temperature line (Fe XVI) while it appeared as a double ribbon (Si XII, Mg X, He) or triple patches (Ne VI, O) in lower temperature lines. We obtained velocity maps in the Fe line that show upward and downward motion concentrated along the eastern and western edge of the sigmoid, respectively.
References
[1]D.M.Rust and A.Kumar, ApJ, 464, L199 (1996)
[2]A.A.Pevtsov, R.C.Canfield, and H.Zirin, ApJ, 473, 533 (1996)
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