Yardley Stephanie L, Brooks David H, D'Amicis Raffaella, Owen Christopher J, Long David M, Baker Deb, Démoulin Pascal, Owens Mathew J, Lockwood Mike, Mihailescu Teodora, Coburn Jesse T, Dewey Ryan M, Müller Daniel, Suen Gabriel H H, Ngampoopun Nawin, Louarn Philippe, Livi Stefano, Lepri Sue, Fludra Andrzej, Haberreiter Margit, Schühle Udo
Department of Mathematics, Physics and Electrical Engineering, Northumbria University, Newcastle Upon Tyne, UK.
Department of Meteorology, University of Reading, Reading, UK.
Nat Astron. 2024;8(8):953-963. doi: 10.1038/s41550-024-02278-9. Epub 2024 May 28.
The ambient solar wind that fills the heliosphere originates from multiple sources in the solar corona and is highly structured. It is often described as high-speed, relatively homogeneous, plasma streams from coronal holes and slow-speed, highly variable, streams whose source regions are under debate. A key goal of ESA/NASA's Solar Orbiter mission is to identify solar wind sources and understand what drives the complexity seen in the heliosphere. By combining magnetic field modelling and spectroscopic techniques with high-resolution observations and measurements, we show that the solar wind variability detected in situ by Solar Orbiter in March 2022 is driven by spatio-temporal changes in the magnetic connectivity to multiple sources in the solar atmosphere. The magnetic field footpoints connected to the spacecraft moved from the boundaries of a coronal hole to one active region (12961) and then across to another region (12957). This is reflected in the in situ measurements, which show the transition from fast to highly Alfvénic then to slow solar wind that is disrupted by the arrival of a coronal mass ejection. Our results describe solar wind variability at 0.5 au but are applicable to near-Earth observatories.
充斥日球层的太阳风起源于日冕中的多个源区，且结构复杂。它通常被描述为来自冕洞的高速、相对均匀的等离子体流，以及低速、变化剧烈的等离子体流，其源区仍存在争议。欧洲航天局/美国国家航空航天局“太阳轨道器”任务的一个关键目标是确定太阳风的源区，并了解是什么导致了日球层中观测到的复杂性。通过将磁场建模和光谱技术与高分辨率观测和测量相结合，我们发现，“太阳轨道器”于2022年3月在原位探测到的太阳风变化是由与太阳大气中多个源区的磁连接的时空变化驱动的。与航天器相连的磁场足点从一个冕洞的边界移动到一个活动区（12961），然后跨越到另一个区域（12957）。这在原位测量中得到了体现，测量结果显示了从快速太阳风到高阿尔文速度太阳风，再到被日冕物质抛射的到来所扰乱的慢速太阳风的转变。我们的结果描述了0.5天文单位处的太阳风变化情况，但也适用于近地观测站。
