arXiv 1504.081292015-04astro-ph.SR

暖太阳日冕环中蒸发-不完全凝结循环的证据

Evidence for evaporation-incomplete condensation cycles in warm solar coronal loops

Clara Froment, Frédéric Auchère, Karine Bocchialini, Eric Buchlin, Chloé Guennou, Jacques Solomon

备注：: 40 pages, 30 figures, accepted for publication in the Astrophysical Journal, v2: corrected typos
DOI：: 10.1088/0004-637X/807/2/158

摘要：

在回路的足点处的准恒定加热导致等离子体的蒸发和冷凝循环：热非平衡（TNE）。这一现象被认为在日冕和日冕雨的形成中发挥了作用。然而，它往往被丢弃，参与加热的暖圈，因为模式不重现的意见。最近的模拟表明，这些与观测结果的不一致可能是由于模型几何形状的过度简化。此外，我们最近的观测表明，长周期强度脉动（几个小时）在太阳日冕环中很常见。这些时期与TNE的预期一致。本文的目的是获得这些事件中的一些等离子体的物理特性，以测试TNE在回路加热中的潜在作用。我们使用SDO/AIA的6个EUV日冕通道详细分析了三个事件。我们进行了差分发射测量（DEM）和时滞分析，包括一种新的方法来隔离相关信号的前景和背景发射。对于这三个事件，DEM经历了长周期的脉动，这是一个周期性加热的签名，即使在冷却阶段捕获的环路，因为是大部分的活动区域。我们将长周期强度脉动与循环加热的新特征联系起来，并提供了蒸发和冷凝循环的有力证据。因此，我们同时见证了广泛的冷却和TNE。最后，我们讨论了静态和脉冲加热模型的影响，我们的新观察。

英文摘要：

Quasi-constant heating at the footpoints of loops leads to evaporation and condensation cycles of the plasma: thermal non-equilibrium (TNE). This phenomenon is believed to play a role in the formation of prominences and coronal rain. However, it is often discarded to be involved in the heating of warm loops as the models do not reproduce observations. Recent simulations have shown that these inconsistencies with observations may be due to oversimplifications of the geometries of the models. In addition, our recent observations reveal that long-period intensity pulsations (several hours) are common in solar coronal loops. These periods are consistent with those expected from TNE. The aim of this paper is to derive characteristic physical properties of the plasma for some of these events to test the potential role of TNE in loop heating. We analyzed three events in detail using the six EUV coronal channels of SDO/AIA. We performed both a Differential Emission Measure (DEM) and a time-lag analysis, including a new method to isolate the relevant signal from the foreground and background emission. For the three events, the DEM undergoes long-period pulsations, which is a signature of periodic heating even though the loops are captured in their cooling phase, as is the bulk of the active regions. We link long-period intensity pulsations to new signatures of loop heating with strong evidence for evaporation and condensation cycles. We thus witness simultaneously widespread cooling and TNE. Finally, we discuss the implications of our new observations for both static and impulsive heating models.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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