论文标题
太阳冠孔的面积如何影响地球附近的高速太阳风流的性质 - 一种分析模型
How the area of solar coronal holes affects the properties of high-speed solar wind streams near Earth -- An analytical model
论文作者
论文摘要
我们得出了一个简单的分析模型，用于从太阳到地球的HSS传播，从而显示冠状孔面积及其边界区域的面积如何影响地球附近的HSS速度，温度和密度。我们认为，靠近太阳的HSS横截面上形成了速度，温度和密度曲线，并且由于太阳旋转，这些空间曲线在给定的径向方向上转化为相应的时间分布。这些时间分布将流界面驱动到前面的慢太阳风等离子体，并以距离太阳的距离分散。然后，从太阳发射的所有HSS等离子体包裹都给出了1 Au处的HSS性能，该属性未进入地球距离的流界面。我们表明，HSSS的速度高原区域如图1所示（如果显而易见）源自HSS的中心区域，靠近太阳，而速度尾部为1 au，源自尾部边界区域。 HSS在地球上的峰值进一步取决于HSS靠近太阳的纵向宽度。地球上HSS等离子体包裹的温度和密度取决于它们从太阳到地球的径向膨胀。径向膨胀取决于靠近太阳的HSS边界区域的速度梯度，并给出地球上的速度温度和密度 - 温度关系。当考虑大量HSS时，HSS速度与接近太阳的温度之间的相关性仅略微降低至1 AU，但是由于径向膨胀，速度和密度之间的相关性被强烈破坏至1 AU。最后，我们展示了流相互作用区域中堆积的慢太阳风的颗粒数量如何取决于HSS的速度和密度以及在慢速太阳风等离子体之前。
We derive a simple analytical model for the propagation of HSSs from the Sun to Earth and thereby show how the area of coronal holes and the size of their boundary regions affect the HSS velocity, temperature, and density near Earth. We presume that velocity, temperature, and density profiles form across the HSS cross section close to the Sun and that these spatial profiles translate into corresponding temporal profiles in a given radial direction due to the solar rotation. These temporal distributions drive the stream interface to the preceding slow solar wind plasma and disperse with distance from the Sun. The HSS properties at 1 AU are then given by all HSS plasma parcels launched from the Sun that did not run into the stream interface at Earth distance. We show that the velocity plateau region of HSSs as seen at 1 AU, if apparent, originates from the center region of the HSS close to the Sun, whereas the velocity tail at 1 AU originates from the trailing boundary region. The peak velocity of HSSs at Earth further depends on the longitudinal width of the HSS close to the Sun. The temperature and density of HSS plasma parcels at Earth depend on their radial expansion from the Sun to Earth. The radial expansion is determined by the velocity gradient across the HSS boundary region close to the Sun and gives the velocity-temperature and density-temperature relationships at Earth their specific shape. When considering a large number of HSSs, the presumed correlation between the HSS velocities and temperatures close to the Sun degrades only slightly up to 1 AU, but the correlation between the velocities and densities is strongly disrupted up to 1 AU due to the radial expansion. Finally, we show how the number of particles of the piled-up slow solar wind in the stream interaction region depends on the velocities and densities of the HSS and preceding slow solar wind plasma.
