Dynamics of solar coronal loops. I. Condensation in cool loops and its effect on transition region lines
Title | Dynamics of solar coronal loops. I. Condensation in cool loops and its effect on transition region lines |
Publication Type | Journal Article |
Year of Publication | 2003 |
Authors | Müller, D. A. N., Hansteen V. H., and Peter H. |
Journal | Astronomy and Astrophysics |
Volume | 411 |
Pagination | 605-613 |
Date Published | Dec |
Abstract | We report numerical calculations of the condensation of plasma in short coronal loops, which have several interesting physical consequences. Firstly, we propose a connection between small, cool loops (T łt} 10⁶ K), which constitute one of the basic components of the solar transition region, and prominences, in the sense that the same physical mechanism governs their dynamics: Namely the onset of instability and runaway cooling due to strong radiative losses. Secondly, we show that the temporal evolution of these loop models exhibits a cyclic pattern of chromospheric evaporation, condensation, motion of the condensation region to either side of the loop, and finally loop reheating with a period of 4000-8000 s for a loop of 10 Mm length. Thirdly, we have synthesized transition region lines from these calculations which show strong periodic intensity variations, making condensation in loops a candidate to account for observed transient brightenings of solar transition region lines. Remarkably, all these dynamic processes take place for a heating function which is constant in time and has a simple exponential height dependence. |
DOI | 10.1051/0004-6361:20031328 |
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