科研之友
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摘要
A nanoflare-heated coronal loop model is developed based on the model of Vekstein & Katsukawa. We performed numerical simulations based on the model, and then compared the results with the Yohkoh/Soft X-ray Telescope (SXT) and Transition Region and Coronal Explorer (TRACE) observations. We found that the most significant difference between hot (> 2 MK) SXT loops and cool (similar to 1 MK) TRACE loops is the energy of nanoflares and the magnetic field strength. Energy of individual nanoflares is 10(24-25) erg for SXT loops, and 10(23) erg for TRACE loops. This is derived from the observed intensity fluctuations. To observed mean intensities, we require the model SXT loops to have a stronger magnetic field than the TRACE loops, 40 G and 8 G, respectively. The model predicts two characteristic properties of nanoflare-heated coronal loops: (1) the SXT and TRACE light curves of a coronal loop show weak cross-correlation with a lag time corresponding to the cooling timescale. (2) SXT loops have a smaller volumetric filling factor than TRACE loops. We consider that this difference in the filling factor makes SXT loops look more diffuse than TRACE loops.
- 出版日期2009-10-1
- 单位中国科学院国家天文台
