Understanding the chromosphere-corona interface in the Solar Orbiter and DKIST era

经过近20年的艰苦工作、规划和建设，这两个下一代长期主要太阳能设施将于2020年初投入运营。这是DKIST和ESA的太阳轨道器。它们有望提供对太阳色球/日冕的突破性观测。DKIST是第一个大型太阳望远镜，有一个4米的离轴反射镜。它建在夏威夷毛伊岛，将于2019年首次点亮，并于2020年开始运行，以前所未有的空间分辨率进行磁盘上和磁盘外观测。DKIST有广泛的盘上仪器来观察光球/色球，但也将投入大约一半的时间用于日冕谱观测，禁止日冕线，1.5太阳半径。我们的目标是通过与DKIST结合密度，温度和磁场的测量来研究日冕的加热。色球层和日冕之间的能量和质量的转移仍然知之甚少。这个模型是非常复杂的，因为它需要非局部输运和时变非平衡原子过程与MHD模型相结合。该建议的一个关键方面是通过在原子速率的计算中加入密度依赖和光电离来改进色球/过渡区原子过程的建模。太阳轨道飞行器是欧空局的一项主要任务，将于2020年2月发射，致力于研究日球层的内部，日球层是太阳系所在的气泡，不断受到太阳事件的影响。其中一些事件与空间天气有关，即对地球大气层外层产生重大影响，例如对卫星、人类空间飞行和通信造成重大影响。太阳轨道飞行器的主要科学目标之一是了解太阳风是如何以及在哪里被释放并从太阳表面加速到日球层的。为了实现这一目标，该任务将与太阳进行近距离接触（在0.3 AU以内），并配备一套原位和遥感仪器。其中一个主要的遥感仪器是SPICE，这是一个在英国RAL建造的紫外光谱仪，能够测量多普勒流，温度和化学丰度，我们将使用它来定位现场观测到的太阳风的来源区域并研究太阳风的形成。SPICE将主要观察在色球-日冕界面形成的线条，因此它将适合于研究太阳过渡区，即太阳色球和日冕之间的薄层大气。这个区域是非常动态的，为了解释观测结果，需要改进原子过程的建模，并包括非平衡效应。我们的目标是继续为当前和未来太阳任务的观测解释提供最基本的原子数据。我们的团队，特别是Giulio Del Zanna，通过不断更新CHIANTI原子数据库一直引领着这一领域，现在也广泛用于研究天体物理学和实验室等离子体。最后，我们将向公众和学校宣传我们的工作。海伦梅森，一位著名的沟通者将在这方面发挥关键作用。

After almost 20 years of hard work, planning and building, the two next-generation long-term major solar facilities will become operational in early 2020. These are DKIST and ESA's Solar Orbiter. They are expected to provide breakthrough observations of the solar chromosphere/corona.DKIST is the first large-scale solar telescope, with a 4 m off-axis mirror. It has been built in Maui, Hawaii, will have first light in 2019 and start operations in 2020 by performing on-disk and off-disk observations with unprecedented spatial resolution. DKIST has a wide range of on-disk instruments to observe the photosphere / chromosphere, but will also devote about half of the time to coronagraph spectral observations of forbidden coronal lines, out to 1.5 solar radii.We aim to study the heating of the solar corona by combining measurements of densities, temperatures and magnetic fields with DKIST.The transfer of energy and mass between the chromosphere and corona is still poorly understood. The modelling of this is extremely complex as it requires non-local transport and time-dependent non-equilibrium atomic processes coupled with MHD modelling. A key aspect of the proposal is to improve the modelling of atomic processes in the chromosphere/transition-region by adding density-dependent and photo-ionisation into the calculation of atomic rates.Solar Orbiter is a major ESA mission to be launched in February 2020 and is dedicated to the study of the inner parts of the heliosphere, the bubble where our solar system resides that is constantly modified by events on the Sun. Some of these events have relevance to Space Weather, i.e. affect significantly the outer layers of the Earth atmosphere, causing significant effects on satellites, human space flight and communication, for example.One of the main science goals of Solar Orbiter is to understand how and where the solar wind is released and accelerated from the solar surface into the heliosphere. To achieve this goal, the mission will have close encounters (to within 0.3 AU) with the Sun, and has a suite of in-situ and remote-sensing instruments. One of the main remote sensing instruments is SPICE, a UV spectrometer built at RAL (UK) that is able to measure Doppler flows, temperatures and chemical abundances, which we shall use to locate the source region of the solar wind observed in-situ and to study the formation of the solar wind.SPICE will mainly observe lines formed in the chromosphere-corona interface, so it will be suited to studies of the solar transition region, the thin layer of theatmosphere between the chromosphere and corona of the Sun. This region is very dynamic, and improved modelling of atomic processes, together with the inclusion of non-equilibrium effects will be required for the interpretation of the observations.We also aim to continue to provide the most fundamental atomic data for the interpretation of the observations of current and future solar missions. Our group, in particular Giulio Del Zanna, has been leading this field by continuously updating the CHIANTI atomic database, now also widely used to study astrophysical and laboratory plasma.Finally, we shall communicate our work to the public and to schools. Helen Mason, a well known communicator will play a key role in this regard.