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首页> 外文期刊>The Astrophysical journal >Heating and Cooling of Coronal Loops with Turbulent Suppression of Parallel Heat Conduction
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Heating and Cooling of Coronal Loops with Turbulent Suppression of Parallel Heat Conduction

机译:湍流抑制平行热传导的冠状环的加热和冷却

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Using the "enthalpy-based thermal evolution of loops" (EBTEL) model, we investigate the hydrodynamics of the plasma in a flaring coronal loop in which heat conduction is limited by turbulent scattering of the electrons that transport the thermal heat flux. The EBTEL equations are solved analytically in each of the two (conduction-dominated and radiation-dominated) cooling phases. Comparison of the results with typical observed cooling times in solar flares shows that the turbulent mean free path lies in a range corresponding to a regime in which classical (collision-dominated) conduction plays at most a limited role. We also consider the magnitude and duration of the heat input that is necessary to account for the enhanced values of temperature and density at the beginning of the cooling phase and for the observed cooling times. We find through numerical modeling that in order to produce a peak temperature K and a 200?s cooling time consistent with observations, the flare-heating profile must extend over a significant period of time; in particular, its lingering role must be taken into consideration in any description of the cooling phase. Comparison with observationally inferred values of post-flare loop temperatures, densities, and cooling times thus leads to useful constraints on both the magnitude and duration of the magnetic energy release in the loop, as well as on the value of the turbulent mean free path .
机译:使用“基于焓的回路热演化”(EBTEL)模型,我们研究了喇叭形冠状回路中等离子体的流体动力学,在该回路中,导热受到传输热热通量的电子的湍流散射的限制。 EBTEL方程在两个(传导主导和辐射主导)冷却阶段的每一个中都进行了解析求解。将结果与太阳耀斑中典型的冷却时间进行比较,结果表明,湍流的平均自由程位于与经典(碰撞为主)传导最多发挥有限作用的状态相对应的范围内。我们还考虑了热量输入的大小和持续时间,这是考虑冷却阶段开始时温度和密度的增加值以及观察到的冷却时间所必需的。通过数值模型我们发现,为了产生峰值温度K和200?s的冷却时间与观察结果一致,火炬加热曲线必须在相当长的一段时间内保持不变。特别地,在冷却阶段的任何描述中都必须考虑其挥之不去的作用。与耀斑后回路温度,密度和冷却时间的观察推断值进行比较,从而对回路中释放的磁能的大小和持续时间以及湍流平均自由程的值产生了有用的限制。

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