A NANOFLARE HEATING MODEL AND COMPARISON WITH OBSERVATIONS
A NANOFLARE HEATING MODEL AND COMPARISON WITH OBSERVATIONS
复制标题
纳米耀斑加热模型及其与观测结果的比较
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
G. Vekstein
中科院分区：
文献类型：
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作者：
Y. Sakamoto;S. Tsuneta;G. Vekstein
基于Vekstein & Katsukawa的模型，建立了一个由纳米火焰加热的日冕环模型。我们基于该模型进行了数值模拟，然后将结果与Yohkoh/软X射线望远镜（SXT）和过渡区和日冕探测器（TRACE）的观测结果进行了比较。我们发现，热（>2 MK）SXT回路和冷（> 11 MK）TRACE回路之间最显著的差异是纳米片的能量和磁场强度。单个纳米片的能量对于SXT环为1024-25 erg，对于TRACE环为1023 erg。这是从观测到的强度波动中得出的。为了观察到平均强度，我们要求模型SXT回路具有比TRACE回路更强的磁场，分别为40 G和8 G。该模型预测了纳米火焰加热的日冕环的两个特征性质：（1）日冕环的SXT和TRACE光变曲线显示出弱的互相关，其滞后时间对应于冷却时间尺度。(2)SXT定量环的体积填充因子小于TRACE定量环。我们认为这种填充因子的差异使SXT循环看起来比TRACE循环更弥散。
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 (∼1 MK) TRACE loops is the energy of nanoflares and the magnetic field strength. Energy of individual nanoflares is 1024–25 erg for SXT loops, and 1023 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.