Sun-to-Earth Observations and Characteristics of Isolated Earth-Impacting Interplanetary Coronal Mass Ejections During 2008 – 2014

Maričić, Darije; Vršnak, Bojan; Veronig, Astrid; Dumbović, Mateja; Šterc, Filip; Roša, Dragan; Karlica, M.; Hržina, Damir; Romštajn, Ivan

doi:10.1007/s11207-020-01658-4

Cited by 9 publications

(7 citation statements)

References 101 publications

(97 reference statements)

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“…These results are important for better understanding the CME mass evolution due to sheath enlargement. We also support results from Maričić et al (2020), who derived strong correlations between the magnetic field in the sheath and LE, indicating a strong physical relation between these two structures.…”

Section: Discussionsupporting

confidence: 90%

“…frontal region as separate segment with the characteristics of enhanced density and flow speed (e.g., Nieves-Chinchilla et al 2018;Maričić et al 2020). However, there is considerable discussion about the proper interpretation of solar wind characteristics observed in situ ahead of the ICME magnetic ejecta (ME) part and also a lack of statistical studies investigating these structures as function of distance from the Sun.…”

Section: Introductionmentioning

confidence: 99%

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Characteristics and evolution of sheath and leading edge structures of interplanetary coronal mass ejections in the inner heliosphere based on Helios and Parker Solar Probe observations

Temmer

Bothmer

2022

A&A

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Context. We investigated the plasma and magnetic field characteristics of the upstream regions of interplanetary coronal mass ejections (ICMEs) and their evolution as function of distance to the Sun in the inner heliosphere. Results are related both to the development of interplanetary shocks, sheath regions, and compressed solar wind plasma ahead of the magnetic ejecta (ME). Aims. From a sample of 45 ICMEs observed by Helios 1/2 and the Parker Solar Probe, we aim to identify four main density structures; namely shock, sheath, leading edge, and ME itself. We compared characteristic parameters (proton particle density, plasma-beta, temperature, magnetic field strength, proton bulk speed, and duration) to the upstream solar wind in order to investigate the interrelation between the different density structures. Methods. For the statistical investigation, we used plasma and magnetic field measurements from 40 well-observed Helios 1/2 events from 1974-1981. Helios data cover the distance range from 0.3-1 au. For comparison, we added a sample of five ICMEs observed with the Parker Solar Probe from 2019-2021 over the distance range of 0.32-0.75 au. Results. It is found that the sheath structure consists of compressed plasma as a consequence of the turbulent solar wind material following the shock and lies ahead of a region of compressed ambient solar wind. The region of compressed solar wind plasma is typically found directly in front of the magnetic driver and seems to match the bright leading edge commonly observed in remote sensing observations of CMEs. From the statistically derived density evolution over distance, we find the CME sheath becomes denser than the ambient solar wind at about 0.06 au. From 0.09-0.28 au, the sheath structure density starts to dominate over the density within the ME. The ME density seems to fall below the ambient solar wind density over 0.45-1.18 au. Besides the well-known expansion of the ME, the sheath size shows a weak positive correlation with distance, while the leading edge seems not to expand with distance from the Sun. We further find a moderate anti-correlation between sheath density and local solar wind plasma speed upstream of the ICME shock. An empirical relation is derived connecting the ambient solar wind speed with sheath and leading edge density. We provide constraints to these results in this paper. Conclusions. The average starting distance for actual sheath formation could be as close as 0.06 au. The early strong ME expansion quickly ceases with distance from the Sun and might lead to a dominance in the sheath density between 0.09 and 0.28 au. The leading edge can be understood as a separate structure of compressed ambient solar wind directly ahead of the ME and is likely the bright leading edge of CMEs often seen in coronagraph images. The results allow for better interpretation of ICME evolution and possibly the observed mass increase due to enlargement of the sheath material. The empirical relation between sheath and leading edge density and ambient solar wind speed...

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Section: Discussionsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Characteristics and evolution of sheath and leading edge structures of interplanetary coronal mass ejections in the inner heliosphere based on Helios and Parker Solar Probe observations

Temmer

Bothmer

2022

A&A

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“…We note that the majority of the remaining events have a latitude and longitude within ±30 • from the center of the solar disk as obtained by GCS. This, along with a clear MC structure observed in situ, indicates a nose hit (Maričić et al 2020).…”

Section: Methodsmentioning

confidence: 71%

“…We searched for associated CME-ICME pairs in Palmerio et al (2018) for period 2010, in Maričić et al (2020 for period 2010, in Temmer et al (2021 for period 2008, and in Nitta & Mulligan Skov (2017 for period 2010-2016. Altogether, we investigated 63 associated CME-ICME pairs in the time period 2008-2016.…”

Section: Methodsmentioning

confidence: 99%

“…Table1lists 22 events and the results of the GCS reconstruction: longitude, latitude, tilt, aspect ratio, and half-angle. The first column shows the ordinal number of the event and the upper index indicates from which CME-ICME list the association was taken; P stands forPalmerio et al (2018), M stands forMaričić et al (2020), T stands forTemmer et al (2021), and N stands for Nitta…”

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confidence: 99%

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Determination of coronal mass ejection orientation and consequences for their propagation

Martinić

Dumbović

Temmer

et al. 2022

A&A

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Context. The configuration of the interplanetary magnetic field and features of the related ambient solar wind in the ecliptic and meridional plane are different. Therefore, one can expect that the orientation of the flux-rope axis of a coronal mass ejection (CME) influences the propagation of the CME itself. However, the determination of the CME orientation, especially from image data, remains a challenging task to perform. Aim. This study aims to provide a reference to different CME orientation determination methods in the near-Sun environment. Also, it aims to investigate the non-radial flow in the sheath region of the interplanetary CME (ICME) in order to provide the first proxy to relate the ICME orientation with its propagation. Methods. We investigated 22 isolated CME-ICME events in the period 2008–2015. We determined the CME orientation in the near-Sun environment using the following: (1) a 3D reconstruction of the CME with the graduated cylindrical shell (GCS) model applied to coronagraphic images provided by the STEREO and SOHO missions; and (2) an ellipse fitting applied to single spacecraft data from SOHO/LASCO C2 and C3 coronagraphs. In the near-Earth environment, we obtained the orientation of the corresponding ICME using in situ plasma and field data and also investigated the non-radial flow in its sheath region. Results. The ability of GCS and ellipse fitting to determine the CME orientation is found to be limited to reliably distinguish only between the high or low inclination of the events. Most of the CME-ICME pairs under investigation were found to be characterized by a low inclination. For the majority of CME-ICME pairs, we obtain consistent estimations of the tilt from remote and in situ data. The observed non-radial flows in the sheath region show a greater y direction to z direction flow ratio for high-inclination events, indicating that the CME orientation could have an impact on the CME propagation.

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Solar Cycle Dependence of ICME Composition

Song

Sun

et al. 2021

Sol Phys

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Coronal mass ejections (CMEs) belong to the most energetic explosions in the solar atmosphere, and their occurrence rates exhibit obvious solar cycle dependence with more events taking place around solar maximum. Composition of interplanetary CMEs (ICMEs), referring to the charge states and elemental abundances of ions, opens an important avenue to investigate CMEs. In this paper, we conduct a statistical study on the charge states of five elements (Mg, Fe, Si, C, and O) and the relative abundances of six elements (Mg/O, Fe/O, Si/O, C/O, Ne/O, and He/O) within ICMEs from 1998 to 2011, and find that all the ICME compositions possess a solar cycle dependence. All of the ionic charge states and most of the relative elemental abundances are positively correlated with sunspot numbers (SSNs), and only the C/O ratios are inversely correlated with the SSNs. The compositions (except the C/O) increase with the SSNs during the ascending phase (1998–2000 and 2009–2011) and remain elevated during solar maximum and descending phase (2000–2005) compared to solar minimum (2007–2009). The charge states of low-FIP (first ionization potential) elements (Mg, Fe, and Si) and their relative abundances are correlated well, while no clear correlation is observed between the C6+/C5+ or C6+/C4+ and C/O. Most interestingly, we find that the Ne/O ratios of ICMEs and slow solar wind have the opposite solar cycle dependence.

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Sun-to-Earth Observations and Characteristics of Isolated Earth-Impacting Interplanetary Coronal Mass Ejections During 2008 – 2014

Cited by 9 publications

References 101 publications

Characteristics and evolution of sheath and leading edge structures of interplanetary coronal mass ejections in the inner heliosphere based on Helios and Parker Solar Probe observations

Characteristics and evolution of sheath and leading edge structures of interplanetary coronal mass ejections in the inner heliosphere based on Helios and Parker Solar Probe observations

Determination of coronal mass ejection orientation and consequences for their propagation

Solar Cycle Dependence of ICME Composition

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