Coronal Loop Interactions Observed In Optical Emission Lines

  • R. N. Smartt
  • V. S. Airapetian
  • Z. Zhang

Abstract

Optical coronagraph observations reveal coronal loop interactions in the form of transient localized brightenings (Smartt and Zhang, 1987; Zhang and Smartt, 1991; Smartt et al, 1993). These appear sequentially in time in the three coronagraph channels, showing first in Fe XIV green-line (530.3 nm; T ∼ 2 × 106K) emission, then in Fe X red-line (637.45 nm; T∼ 106K) emission, and finally in Hα. This sequence (∼20 minutes) reveals cooling of the plasma at the interaction site following initiation of the interaction. Since an enhancement is not normally observed in a red-line image prior to a corresponding maximum appearing in a green-line image, it is inferred that the plasma is heated rapidly during initial coalescence. The maximum value for the temperature immediately following the initiation of energy release in a particular event was estimated as, Tmax < 5 x 106K (Airapetian and Smartt, 1995). This indicates that for this, and similar, events, the plasma is already cooling when the maximum in the green-line image occurs

Keywords

Solar Flare Interaction Site Radiative Cool Thermal Instability Loop Interaction 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Kluwer Academic Publishers 1996

Authors and Affiliations

  • R. N. Smartt
    • 1
  • V. S. Airapetian
    • 2
  • Z. Zhang
    • 3
  1. 1.National Solar ObservatorySacramento PeakSunspotUSA
  2. 2.CSC/NASA/GSFCGreenbeltUSA
  3. 3.Department of AstronomyUniversity of NanjingChina

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