WHERE IS THE CHROMOSPHERIC RESPONSE TO CONDUCTIVE ENERGY INPUT FROM A HOT PRE-FLARE CORONAL LOOP?
WHERE IS THE CHROMOSPHERIC RESPONSE TO CONDUCTIVE ENERGY INPUT FROM A HOT PRE-FLARE CORONAL LOOP?
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DOI：
10.1088/0004-637x/789/1/47
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发表时间：
2014-05
期刊：
影响因子：
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通讯作者：
M. Battaglia;L. Fletcher;P. Simões
中科院分区：
文献类型：
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作者：
M. Battaglia;L. Fletcher;P. Simões
在硬 X 射线中观察到耀斑开始之前，通常有一个延长的预耀斑或预热阶段，没有可检测到的硬 X 射线发射，但有明显的软 X 射线发射，这表明在此阶段能量已经被释放并沉积到日冕和色球层中。这项工作分析了日冕源加热的时间演化以及预热阶段的色球响应，以研究太阳耀斑期间早期能量释放和传输的起源和性质。对具有延长预热阶段的良好观测耀斑进行同步 X 射线、EUV 和微波观测分析，以研究热发射的时间演化并确定粒子加速的开始。在预热阶段的 20 分钟期间，我们在硬 X 射线或微波发射中没有发现加速电子的迹象。然而，预热阶段的总能量预算表明，必须向火炬循环提供能量以维持观察到的温度和排放量。假设该能量通过热传导向色球层传输，预计在色球层会出现大量的能量沉积。然而，没有观察到对色球温度敏感的 AIA 波长通道中的发射增加。观测结果表明，在粒子加速开始之前，能量在耀斑环中释放和沉积，但观测结果不支持将能量传导至色球层并随后加热色球层的模型。
Before the onset of a flare is observed in hard X-rays, there is often a prolonged pre-flare or pre-heating phase with no detectable hard X-ray emission but pronounced soft X-ray emission, which suggests that energy is already being released and deposited into the corona and chromosphere at this stage. This work analyzes the temporal evolution of coronal source heating and the chromospheric response during this pre-heating phase to investigate the origin and nature of early energy release and transport during a solar flare. Simultaneous X-ray, EUV, and microwave observations of a well-observed flare with a prolonged pre-heating phase are analyzed to study the time evolution of the thermal emission and to determine the onset of particle acceleration. During the 20 minute duration of the pre-heating phase we find no hint of accelerated electrons in either hard X-rays or microwave emission. However, the total energy budget during the pre-heating phase suggests that energy must be supplied to the flaring loop to sustain the observed temperature and emission measure. Under the assumption of this energy being transported toward the chromosphere via thermal conduction, significant energy deposition at the chromosphere is expected. However, no detectable increase of the emission in the AIA wavelength channels sensitive to chromospheric temperatures is observed. The observations suggest energy release and deposition in the flaring loop before the onset of particle acceleration, yet a model in which energy is conducted to the chromosphere and subsequent heating of the chromosphere is not supported by the observations.