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（solar wind）与空间天气（space weather）事件对太阳系具有显著影响，且会对航天及地面技术系统构成威胁。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，低日冕（lower corona）中的冕洞（coronal holes）、盔状冕流（helmet streamers）与日珥（prominences）等磁结构，是驱动太阳风及日冕物质抛射（CME）的关键因素。然而，由于该区域无法通过空间探测器（space probes）直接抵达，目前针对低太阳高度（<20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，我们计划对一批脉冲星（pulsars）开展观测，追踪其行经太阳5.7度天区范围内的过程。借助帕克斯射电望远镜（Parkes Radio Telescope）的UWL接收机（UWL receiver），我们将对脉冲信号的色散群延迟（dispersive group delay）与法拉第旋转（Faraday rotation）进行高精度测量。此举将使我们能够探究驱动太阳风的日冕结构的密度与磁场特征，并机遇性地观测到约6±4次途经观测脉冲星的日冕物质抛射事件。我们还将把该观测数据与行星际闪烁（interplanetary scintillation）法研究太阳风的相关工作、空间探测器的观测约束及数值模拟结果进行整合。本研究方案为全面理解太阳风与空间天气提供了极具前景的契机。