AI 中文总结
本文研究辐射主导等离子体中受激轫致辐射散射对电子输运的影响，重新评估输运系数，解释耀斑观测信号，发现该散射是耀斑关键碰撞过程，相关系数可用于辐射MHD代码。
AI 中文摘要
太阳日冕中存在的微波辐射可增强快电子与离子的轫致辐射散射，该过程可解释电子沿磁环的扩散输运及高沉降率，还可主导被约束在这类磁环中的热电子输运。本文研究受激轫致辐射散射对电子输运的影响，重点关注被捕获在磁环中的快电子群感应的返回电流。整体而言，本文重新评估了辐射主导等离子体中的输运系数，该等离子体的特征是辐射对轫致辐射电子-离子碰撞的受激作用，作用范围可低至热速度。本文开发了由光子谱中明亮的低频宽频部分驱动的电子输运理论框架，并计算了一组辐射增强的输运系数。来自耀斑的紫外（UV）、极紫外（XEUV）和硬X射线信号证明存在反常电阻率、热传导抑制及快电子的高沉降率，本文对这些信号进行了重新解释。研究发现，受激轫致辐射散射产生的反常电阻率在耀斑中占主导地位，超过经典电阻率；库仑碰撞导致的逃逸效应被抑制；与Spitzer传导相比，热传导受到抑制，这与慢模波的日冕地震学结果一致。受激轫致辐射散射被发现是耀斑事件中的关键碰撞过程，可解释快电子产生的环顶硬X射线信号及热电子的电导率测量值。作为展望，对应的输运系数可用于辐射磁流体力学（radiation MHD）代码，该辐射模型也可应用于在研究太阳日冕的动力学或混合模型中激发大角度电子散射。
英文摘要
Bremsstrahlung scattering of fast electrons on ions can be enhanced by the microwave radiation present in the solar corona. It can account for the electron diffusive transport along magnetic loops and high precipitation rates. This process can also dominate the transport of thermal electrons confined in such loops. The influence of stimulated Bremsstrahlung scattering on the electron transport is studied, with focus on the return current induced by the fast electron population trapped in magnetic loops. Overall, transport coefficients are reevaluated in the radiation-dominated plasma, characterized by the stimulated action of radiation on the Bremsstrahlung electron-ion collision, down to thermal velocities. We develop a theoretical framework for electron transport driven by a large bandwidth, bright low-frequency part of the photon spectrum and compute a set of radiation-enhanced transport coefficients. UV, XEUV and hard X-ray signals from flares, evidencing anomalous resistivity, thermal conduction inhibition and high precipitation rates of fast electrons, are reinterpreted. The anomalous resistivity due to stimulated Bremsstrahlung scattering is found to dominate the classical resistivity in flares. The runaway effect due to Coulomb collisions is suppressed. Thermal conduction is inhibited compared to the Spitzer conduction, in agreement with coronal seismology of slow-mode waves. Stimulated Bremsstrahlung scattering is found to be a key collisional process in flaring events. It can explain the above loop-top hard X-ray signal due to the fast electrons, and the measured electrical conductivity due to the thermal electrons. As a perspective, the corresponding transport coefficients can be used in radiation MHD codes. The radiation model could also be applied to stimulate large-angle electron scattering in the kinetic or hybrid models used to study the solar corona.
