资源环境科技发展态势分析平台

The addition of Parker Solar Probe (PSP) to the Heliophysics System Observatory has allowed for the unprecedented ability to study Corotating Interaction Regions (CIRs) at multiple radial distances without significant temporal/longitudinal variations. On 2019 September 19, PSP observed a CIR at ∼0.5 au when it was nearly radially aligned with the Solar Terrestrial Relations Observatory‐Ahead (STEREO‐A) spacecraft at ∼1 au, allowing for an unambiguous assessment of the radial evolution of a single CIR. Bulk plasma and magnetic field signatures of the CIR evolve in a fashion characteristic to previous observations, however the suprathermal ions are enhanced over a larger longitudinal range at PSP than at STEREO‐A, although at much lower intensities. The longitudinal spread appears to be largely a consequence of magnetic field line topology at CIRs between the compressed slow solar wind upstream and high‐speed stream following the CIR, underscoring the importance of the large‐scale topology of these structures.

Corotating Interaction Regions (CIRs) form where high‐speed solar wind interacts with slower‐speed solar wind. While these large structures have been extensively studied at the distance of the Earth, the addition of Parker Solar Probe (PSP) to the current fleet of satellites allows for investigations of CIRs at multiple points between the Sun and Earth. This study focuses on an event on 2019 September 19 in which PSP observed a CIR at close to the Sun while being well‐aligned with the Solar Terrestrial Relations Observatory‐Ahead (STEREO‐A) spacecraft. This combination gives a clear view of the evolution of a single CIR from close to the Sun out to the distance of the Earth. While solar wind plasma and magnetic field signatures of the CIR change in a fashion seen previously, the more energetic ions are enhanced over a larger swath at PSP than at STEREO‐A. This spread appears to arise from the large‐scale magnetic field structure of a CIR, highlighting how the energetic particles are connected to these structures along the magnetic field lines. Discerning this is important for understanding future observations of CIRs seen by PSP and for advancing our knowledge of how plasma is energized and transported in interplanetary space.

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