Properties of the Near-Sun Solar Wind

太阳风是一种热的、稀薄的等离子体，它从太阳流向太空深处。在地球上，它与地球磁场的相互作用会产生极光，但也会破坏卫星，扰乱通信和电网。虽然太阳风可以用许多航天器进行采样，我们也有太阳表面和大气的地面测量，但关于太阳是如何产生太阳风的，以及太阳风从源头到到达地球之间是如何演变的，我们仍然不知道很多。2017年，欧洲航天局将发射太阳轨道飞行器，它将在水星轨道内比以往任何时候都更接近太阳，以测量太阳系内部的太阳风。帝国正在为太阳轨道飞行器建造磁场仪器。在准备发射太阳轨道飞行器的过程中，计划重新访问在20世纪70年代和80年代运行的双太阳风航天器对太阳附近太阳风的早期测量。这些测量是高质量的，但在过去的三十年里，计算机能力的进步意味着它们为新发现提供了丰富的选择。还有来自水星轨道上的信使号航天器的最新数据。我们将使用太阳神号和信使号的数据来研究太阳系内部太阳风的基本特性：小尺度的太阳风结构；不同太阳风流的相互作用；以及冲击和湍流的发展。

The solar wind is a hot, tenuous plasma that flows from the Sun into deep space. At the Earth, its interaction with our planet's magnetic field causes the aurora but can also damage satellites and disrupt communications and power grids. Although the solar wind can be sampled with a number of spacecraft, and we have ground based measurements of the Sun's surface and atmosphere, there is still much that we do not know about how the Sun creates the solar wind and how it evolves between its source and its arrival at the Earth.In 2017, the European Space Agency will launch Solar Orbiter, which will travel closer to the Sun than ever before, within Mercury's orbit, to measure the solar wind in the inner solar system. Imperial are building the magnetic field instrument for Solar Orbiter. In preparation for the launch of Solar Orbiter, it is planned to re-visit earlier measurements of the solar wind near the Sun, from the twin Helios spacecraft that were in operation in the 1970's and 1980's. These measurements are high quality, but advances in computer power in the last thirty years mean that they offer rich pickings for new discoveries. There is also more recent data from the Messenger spacecraft in orbit around Mercury.We will be using Helios and Messenger data to study fundamental properties of the solar wind in the inner solar system: small scale solar wind structures; the interactions of different solar wind streams; and the development of shocks and turbulence.