Parkes observations for project P1189 semester 2024OCTS_04

The solar wind and space weather events have a significant impact on the solar system and can pose hazards to both space and Earth-based technologies. Understanding the origins of the solar wind and space weather is therefore essential to comprehend how these events are driven and to enhance space weather prediction efforts. Magnetic structures such as coronal holes, helmet streamers, and prominences in the lower corona are believed to be key 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 aim to monitor a set of pulsars as they pass within 5.7 degrees of the Sun. Using the UWL receiver on the Parkes Radio Telescope, we will make precision measurements of the dispersive group delay and Faraday rotation of the pulses. This will enable us to investigate the densities and magnetic fields of the coronal structures driving the wind and to observe approximately $6 \pm 4$ CMEs as they pass by the pulsars serendipitously. We will integrate this data with complementary efforts to study the solar wind via interplanetary scintillation, constraints from space probes, and simulations. This approach provides an exciting opportunity to develop a comprehensive understanding of the solar wind and space weather.

太阳风与空间天气事件对太阳系具有显著影响，且会对空间及地面技术设施构成威胁。因此，厘清太阳风与空间天气的起源，对于理解此类事件的驱动机制、提升空间天气预报能力至关重要。学界普遍认为，日冕低层中的冕洞（coronal holes）、盔状冕流（helmet streamers）与日珥（prominences）等磁场结构，是驱动太阳风及日冕物质抛射（CMEs）的关键因素。然而，由于该区域无法通过空间探测器直接探测，目前针对太阳高度低于20倍太阳半径区域内的太阳风与空间天气事件的观测约束极为有限。在本研究方案中，我们计划对一批运行至太阳5.7度视场内的脉冲星（pulsars）开展监测。借助帕克斯射电望远镜（Parkes Radio Telescope）上的UWL接收机（UWL receiver），我们将对脉冲信号的色散群时延（dispersive group delay）与法拉第旋转（Faraday rotation）进行高精度测量。此举将帮助我们探究驱动太阳风的日冕结构的密度与磁场特征，并通过偶然机遇观测到约6±4次掠过脉冲星的日冕物质抛射事件。我们将把该数据集与其他互补研究手段相结合：包括通过行星际闪烁（interplanetary scintillation）探测太阳风的相关工作、空间探测器的观测约束，以及数值模拟结果。该研究方案为我们全面掌握太阳风与空间天气的物理机制提供了极具前景的机遇。