Radial evolution of the April 2020 stealth coronal mass ejection between 0.8 and 1 AU. Comparison of Forbush decreases at Solar Orbiter and near the Earth
Radial evolution of the April 2020 stealth coronal mass ejection between 0.8 and 1 AU. Comparison of Forbush decreases at Solar Orbiter and near the Earth
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2020 年 4 月隐形日冕物质抛射在 0.8 到 1 个天文单位之间的径向演化。
DOI：
10.1051/0004-6361/202039848
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发表时间：
2021
影响因子：
6.5
通讯作者：
M. Yedla
中科院分区：
文献类型：
--
作者：
J. V. Forstner;M. Dumbovi'c;C. Mostl;Jingnan Guo;A. Papaioannou;R. Elftmann;Zigong Xu;J. Terasa;A. Kollhoff;R. Wimmer–Schweingruber;J. Rodr'iguez;A. Weiss;J. Hinterreiter;T. Amerstorfer;M. Bauer;A. Belov;M. Abunina;T. Horbury;E. Davies;H. O’Brien;R. Allen;G. Andrews;L. Berger;S. Boden;I. C. Cangas;S. Eldrum;F. Lara;R. Herrero;J. Hayes;G. Ho;S. Kulkarni;W. Lees;C. Mart'in;G. Mason;D. Pacheco;M. P. Mateo;A. Ravanbakhsh;Ó. Polo;S. Prieto;C. Schlemm;H. Seifert;K. Tyagi;M. Yedla
目标。我们介绍了2020年4月19日太阳轨道器航天器观测到的第一次日冕物质抛射（CME）以及高能望远镜（HET）测量的相关福布什减少（FD）。这次CME是一个多航天器事件，第二天也在地球附近看到。方法.我们强调的HET观测小的短期变化的银河宇宙射线计数率使用其单探测器计数器的能力。我们将分析ForbMod模型应用于FD测量，以重现两个位置的Forbush下降。模型的输入参数来自CME的现场和遥感观测。结果非常缓慢的隐形CME（约350 kms − 1）在HET的低能宇宙射线测量中造成了3%的FD，在月球勘测轨道飞行器上的宇宙射线望远镜（CRaTER）的可比通道中造成了2%的FD，以及中子监测器测量值下降了1%。CME在不同位置的膨胀行为存在显著差异，这可能与以下高速太阳风流的影响有关。在一定的假设下，ForbMod能够再现HET和CRaTER在低能宇宙线测量中观察到的FD，然而，在相同的输入参数下，结果与地球上中子监测器测量的更高能量下的FD幅度不一致。我们研究这些差异，并提供可能的解释。结论.这项研究强调了这样一个概念，即太阳轨道器的新测量可以与其他航天器的观测相协调，以提高我们对日光层内部空间天气的理解。多航天器观测与基于数据的建模相结合，对于了解日冕物质抛射的传播和演变及其空间天气影响也至关重要。
Aims. We present observations of the first coronal mass ejection (CME) observed by the Solar Orbiter spacecraft on April 19, 2020 and the associated Forbush decrease (FD) measured by the High Energy Telescope (HET). This CME is a multi-spacecraft event that was also seen near Earth the following day. Methods. We highlight the capabilities of the HET for observing small short-term variations of the galactic cosmic ray count rate using its single detector counters. We applied the analytical ForbMod model to the FD measurements to reproduce the Forbush decrease at both locations. Input parameters for the model were derived from both in situ and remote-sensing observations of the CME. Results. The very slow ( ∼ 350kms − 1 ) stealth CME caused an FD with an amplitude of 3% in the low-energy cosmic ray measurements at HET and 2% in a comparable channel of the Cosmic Ray Telescope for the E ff ects of Radiation (CRaTER) on board the Lunar Reconnaissance Orbiter, as well as a 1% decrease in neutron monitor measurements. Significant di ff erences are observed in the expansion behavior of the CME at di ff erent locations, which may be related to influence of the following high speed solar wind stream. Under certain assumptions, ForbMod is able to reproduce the observed FDs in low-energy cosmic ray measurements from HET as well as CRaTER, however, with the same input parameters, the results do not agree with the FD amplitudes at higher energies measured by neutron monitors on Earth. We study these discrepancies and provide possible explanations. Conclusions. This study highlights the notion that the novel measurements of Solar Orbiter can be coordinated with observations from other spacecraft to improve our understanding of space weather in the inner heliosphere. Multi-spacecraft observations combined with data-based modeling are also essential for understanding the propagation and evolution of CMEs, in addition to their space weather impacts.