The question of what heats the outer solar atmosphere remains one of the longstanding mysteries in astrophysics. Statistical studies of Sun-like stars reveal a correlation between global chromospheric and coronal emissions, constraining theoretical models of potential heating mechanisms. However, spatially resolved observations of the Sun have surprisingly failed to show a similar correlation on small spatial scales. Here we use unique coordinated observations of the chromosphere (from the IRIS satellite) and the low corona (from the Hi-C 2.1 sounding rocket), and machine-learning-based inversion techniques, to show a strong correlation on spatial scales of a few hundred kilometres between heating in the chromosphere and emission in the upper transition region in strong magnetic field regions (‘plage’). Our observations are compatible with an advanced three-dimensional magnetohydrodynamic simulation in which the dissipation of current sheets caused by magnetic field braiding is responsible for heating the plasma simultaneously to chromospheric and coronal temperatures. Our results provide deep insight into the nature of the heating mechanism in solar active regions.

是什么加热了太阳外层大气的问题仍然是天体物理学中长期存在的谜团之一。对类太阳恒星的统计研究揭示了全球色球层和日冕发射之间的相关性，限制了潜在加热机制的理论模型。然而，令人惊讶的是，对太阳的空间分辨观测未能在小空间尺度上显示出类似的相关性。在这里，我们使用对色球层（来自 IRIS 卫星）和低日冕（来自 Hi-C 2.1 探空火箭）的独特协调观测，以及基于机器学习的反演技术，以显示一些空间尺度上的强相关性。色球层的加热和强磁场区域（“plage”）上部过渡区域的发射之间有数百公里。我们的观察结果与先进的三维磁流体动力学模拟兼容，其中由磁场编织引起的电流片耗散负责将等离子体同时加热到色球和日冕温度。我们的研究结果提供了对太阳活动区域加热机制本质的深入了解。