Magnetic tornadoes as energy channels into the solar corona

摘要

太阳外层大气明显要比表面更热，超过100万开氏度，但充足的能量是怎样转移和耗散的一直是个谜。在对太阳表面上小尺度结构进行的高分辨率成像方面所取得的最新进展(其结果来自“瑞典1．米太阳望远镜”)，显示了太阳色球(夹在日冕和光球之间的大气层)中的涡流事件。这篇论文报告了来自NASA的“太阳动力学观测卫星”的观测结果。这些结果显示，在过渡区域和低日冕区域存在快速转动的磁结构，它们与色球的这些涡流相关。这些结构(与太阳条件下的超级龙卷风相似)从对流区域进入上层太阳大气，为将能量从低层太阳大气输送到上层太阳大气提供了另外一个机制，也为将太阳外层大气加热到所观测到的温度提供了一个可能的解释。本期封面所示为对将所观测的太阳表面与外层大气连接起来的一个涡rn流磁性“龙卷风”所做的个电脑模拟结果(利用C05BOL．D来进行)进行的虚拟化(利用VAF，OR软件来进行)%Heating the outer layers of the magnetically quiet solar atmosphere to more than one million kelvin and accelerating the solar wind requires an energy flux of approximately 100 to 300 watts per square metre, but how this energy is transferred and dissipated there is a puzzle and several alternative solutions have been proposed. Braiding and twisting of magnetic field structures, which is caused by the convective flows at the solar surface, was suggested as an efficient mechanism for atmospheric heating. Convectively driven vortex flows that harbour magnetic fields are observed to be abundant in the photosphere (the visible surface of the Sun). Recently, corresponding swirling motions have been discovered11 in the chromosphere, the atmospheric layer sandwiched between the photosphere and the corona. Here we report the imprints of these chromospheric swirls in the transition region and low corona, and identify them as observational signatures of rapidly rotating magnetic structures. These ubiquitous structures, which resemble super-tornadoes under solar conditions, reach from the convection zone into the upper solar atmosphere and provide an alternative mechanism for channelling energy from the lower into the upper solar atmosphere.