Energy Transport in Solar Flares

在过去的几年里，在很大程度上，由于从NASA太阳极大期任务（SMM）和日本日之鸟（Hinotori）等航天器观测站获得的数据，太阳耀斑脉冲阶段的全球图景已经开始出现，其中不同光谱区域的辐射特征都被认为反映了相同的潜在物理过程。航天器数据表明，硬x射线源在时间和空间上的演变与预测的大气对高能电子束碰撞退化的耀斑能量输入的响应一致。软x射线的谱线轮廓揭示了等离子体发射的测量和速度，这与这里资助的小组对这些电子束能量传输计算的预测大体一致。这些和其他的结果是令人鼓舞的，因为在宽波长范围内的观测确实可以用来解决太阳耀斑物理学的两个最基本的问题——一次能量释放的性质和原因，以及能量传输过程的物理学。理论和观测之间的相互作用已经远远超出了对定性图像的简单比较。我们现在正处于这样一个阶段，理论预测可以用来完善理论模型，从而增加我们对工作中的基本物理学的理解。这笔拨款将支持一项工作计划，以继续这一有利可图的分析路线。它将讨论耀斑能量传输过程的诊断，特别是在硬x射线，软x射线和EUV中由超热电子的加速和退化引起的耀斑能量传输过程。此外，它将在耀斑脉冲阶段的图像中严格检查能量释放和传输的物理学，改进现有模型以包括迄今为止只受到很少关注的效应，如反向电流，等离子体集体过程和非均匀磁场几何。

Over the past few years, in great part due to the acquisition of data from spacecraft observatories such as the NASA Solar Maximum Mission (SMM) and the Japanese Hinotori, a global picture of the impulsive phase of solar flares has started to emerge, in which the radiation signatures in different spectral regions are all seen to reflect the same underlying physical processes. The spacecraft data show that the hard X-ray source evolves temporally and spatially in a manner which is consistent with the predicted response of the atmosphere to flare energy input by collisional degradation of energetic electron beams. Spectral line profiles in soft X-rays reveal plasma emission measures and velocities which are broadly consistent with the predictions of these electron beam energy transport calculations of the group funded here. These and other results are encouraging, because observations over a wide range of wavelengths can indeed be used to address two of the most fundamental questions of solar flare physics - the nature and cause of the primary energy release, and the physics of the energy transport processes. The interplay between theory and observation has progressed well beyond a simple comparison of qualitative pictures. We are now at a stage where theoretical predictions can be used to refine theoretical models and so increase our understanding of the basic physics at work. This grant will support a program of work to continue this profitable line of analysis. It will address diagnostics of flare energy transport processes, notably those resulting from the acceleration and degradation of suprathermal electrons, in hard X-rays, soft X-rays, and EUV. In addition, it will critically examine the physics of the energy release and transport in such a picture of the impulsive phase of flares, refining existing models to include effects which have hitherto received only scant attention, such as reverse currents, plasma collective processes and non-uniform magnetic field geometry.