Parkes observations for project P1189 semester 2023OCTS_02

The solar wind and space weather events have a crucial influence on the solar system, and can present a hazard to space and Earth-based technologies. Understanding the origins of the solar wind and space weather is therefore crucial, so that we can better understand how these events are driven, and to improve space weather prediction efforts. In particular, magnetic structures such as coronal holes, helmet streamers, and prominences in the lower corona are thought to be crucial drivers of the winds and coronal mass ejections (CMEs). However, there are very few observational constraints on the solar wind and space weather events at low solar altitudes (< 20 solar radii), as this region is inaccessible to space probes. In this proposal, we seek to monitor a set of pulsars as they pass within 5.7 degrees of the Sun. We will use the UWL receiver on the Parkes Radio Telescope to make precision measurements of the dispersive group delay and Faraday rotation of the pulses. This will enable us to probe the densities and magnetic fields of the coronal structures driving the wind, and probe $6 \pm 4$ CMEs as they pass by the pulsars serendipitously. We will tie this information together with complementary efforts to probe the solar wind via interplanetary scintillation, constraints from space probes, and simulations. This will give us an exciting opportunity to form a holistic picture of the solar wind and space weather.太阳风与空间天气事件对太阳系具有至关重要的影响，同时会对太空及地面技术设施构成威胁。因此，探明太阳风与空间天气的起源至关重要——这不仅有助于我们更好地理解此类事件的驱动机制，还能助力空间天气预报能力的提升。具体而言，日冕低层中的冕洞、盔状冕流与日珥等磁结构，被认为是驱动太阳风及日冕物质抛射（CMEs）的核心因素。然而，由于该区域无法通过空间探测器抵达，目前针对太阳低高度（<20倍太阳半径）范围内的太阳风与空间天气事件的观测约束极为有限。在本研究提案中，我们计划对一批运行至太阳5.7度角距范围内的脉冲星开展观测。我们将借助帕克斯射电望远镜上的UWL接收机（UWL receiver），对脉冲信号的色散群延迟与法拉第旋转开展高精度测量。通过此项观测，我们将能够探测驱动太阳风的日冕结构的密度与磁场，并对偶然掠过脉冲星的6±4次日冕物质抛射（CMEs）开展研究。我们将把这些观测数据与多项互补研究手段相结合：包括通过行星际闪烁探测太阳风、利用空间探测器获取的观测约束，以及数值模拟结果。这将为我们全面构建太阳风与空间天气的完整图景提供难得的机遇。