Article
Astronomy & Astrophysics
Alexander W. James, David R. Williams, Jennifer O'Kane
Summary: This study aims to quantify the variation of critical height for torus instability-driven CMEs over time in solar active regions, and finds that the rate of CMEs is significantly higher when the critical height is increasing during phases of magnetic flux increase. Additionally, the critical height is generally proportional to the separation of magnetic polarities in the active regions.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
P. Vemareddy
Summary: Magnetic helicity is a measure of twist and shear of magnetic field, and understanding the nature and evolution of photospheric helicity flux transfer is crucial in revealing the intensity of flare and coronal mass ejection activity. Through studying time-sequence vector magnetograms, it is found that injection of magnetic helicity with different signs can lead to magnetic field reconnection, resulting in intermittent flares and enhanced coronal heating.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
E. Lumme, J. Pomoell, D. J. Price, E. K. J. Kilpua, M. D. Kazachenko, G. H. Fisher, B. T. Welsch
Summary: This study utilized a data-driven, time-dependent magnetofrictional simulation to examine the pre- and post-eruptive evolution of a solar eruption and highlight the strengths and weaknesses of the simulation approach. The results demonstrate the simulation's effectiveness in modeling the pre-eruptive flux rope system but indicate difficulties in reproducing the post-eruptive ejection.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Abd-ur Raheem, Huseyin Cavus, Gani Caglar Coban, Ahmet Cumhur Kinaci, Haimin Wang, Jason T. L. Wang
Summary: This study identified the source active regions for the majority of CMEs using a filtration process and machine learning to compare the physical parameters of sunspot groups with properties of CMEs to uncover the mechanisms behind CME initiation. The neural network successfully identified source HARPs for 4895 out of 14604 CMEs recorded from 2011 to 2020, showing the effectiveness of the method in source region identification.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
X. J. Zhang, L. H. Deng, Z. P. Qiang, Y. Fei, X. A. Tian, C. Li
Summary: This research investigates the hemispheric asymmetry of coronal mass ejections (CMEs) between 1996 and 2020, and finds that the hemispheric asymmetry of CMEs is mainly caused by specific CMEs rather than regular CMEs. The hemispheric asymmetry of high-latitude CMEs appears to have little connection to that of low-latitude CMEs. The dominant hemisphere, cumulative trend, and amplitude of CMEs vary between different solar cycles.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
S. W. Good, L. M. Hatakka, M. Ala-Lahti, J. E. Soljento, A. Osmane, E. K. J. Kilpua
Summary: Interplanetary coronal mass ejections (ICMEs) exhibit fluctuations in magnetic field and velocity at different scales, with the cross helicity serving as a measure of the balance between these fluctuations. Observations show that ICME flux ropes and sheaths at 1 au have varying levels of cross helicity, suggesting dynamic equilibrium influenced by solar activity.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
K. Martinic, M. Dumbovic, M. Temmer, A. Veronig, B. Vrsnak
Summary: This study investigates different methods for determining the orientation of coronal mass ejections (CMEs) in the near-Sun environment and explores the non-radial flow in the sheath region of interplanetary CMEs (ICMEs). The results show that current methods are limited in accurately determining the orientation of CMEs, but most CMEs have a low inclination. Consistent estimations of the tilt between remote and in situ data were obtained for the majority of CME-ICME pairs. The observed non-radial flows suggest that the CME orientation may impact its propagation.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Beili Ying, Li Feng, Bernd Inhester, Marilena Mierla, Weiqun Gan, Lei Lu, Shuting Li
Summary: This study investigates the formation mechanism of a shock driven by an aspherical CME and demonstrates the impact of the difference in CME's principal radius of curvature on the estimation of shock and coronal parameters. By using three-dimensional reconstructions, the researchers were able to derive corona parameters at high latitudes and analyze the bow-shock formation mechanism.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
L. Rodriguez-Garcia, T. Nieves-Chinchilla, R. Gomez-Herrero, I. Zouganelis, A. Vourlidas, L. A. Balmaceda, M. Dumbovic, L. K. Jian, L. Mays, F. Carcaboso, L. F. G. dos Santos, J. Rodriguez-Pacheco
Summary: The main objective of this study is to investigate the radial and longitudinal evolution of the interplanetary counterpart (ICME) in the inner heliosphere and to examine the different magnetic flux-rope configurations observed on the solar disk and in situ at various locations.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Vincent E. Ledvina, Erika Palmerio, Christina Kay, Nada Al-Haddad, Pete Riley
Summary: The sensitivity of the OSPREI model to different solar magnetic and coronal conditions is reported. It is found that the solar magnetic and coronal conditions affect the evolution of CMEs as they propagate through the Sun's corona and into interplanetary space, as well as the accuracy of MFR prediction. Best practices may exist when selecting an input magnetogram based on the source region of the CME on the Sun.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Q. M. Zhang
Summary: This paper aims to track the three-dimensional evolution of a full halo coronal mass ejection (CME) and uses a revised cone model to derive its morphological and kinematic properties. The results show that the revised cone model fits nicely with the observed CME and the CME exhibits changes in angle and distance over time.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
S. N. A. Syed Zafar, R. Umar, N. H. Sabri, M. H. Jusoh, A. N. Dagang, A. Yoshikawa
Summary: Previous studies have shown that solar activities such as coronal mass ejections and solar flares can lead to the development of storms and high-speed streams. This study investigates the response of the geomagnetic index SYM/H to solar wind parameters, as well as the ground geomagnetic field responses at low-latitude stations. Findings suggest delayed response of the Earth's magnetosphere to weak geomagnetic storms, while strong solar wind and IMF variations can excite the Earth's H-component during geomagnetic storms caused by solar activities.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
S. Mancuso, A. Bemporad, F. Frassati, D. Barghini, S. Giordano, D. Telloni, C. Taricco
Summary: This study reports the first unambiguous observational evidence of the reflection of a coronal shock wave at the boundary of a coronal hole in the radio range. The research utilizes EUV and radio instruments to track and analyze shock wave phenomena and electron beam acceleration processes in the inner corona.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Multidisciplinary Sciences
Alessandro Bemporad
Summary: Due to the lack of UV-EUV observations of CMEs far from the Sun, our understanding of the thermodynamic evolution of these solar phenomena is limited. This study analyzed a slow CME observed in visible and UV light and used the data to determine the distribution of plasma electron density, temperature, and thermal energy. The results showed that the CME core had higher temperatures compared to the surrounding void and front, and the core temperatures increased during the CME expansion, indicating plasma heating processes. The distribution of thermal energy also exhibited asymmetry, possibly due to interaction with nearby coronal structures. This work demonstrates the potential of combining UV and visible light data and future multi-slit spectroscopic observations of CMEs.
Article
Astronomy & Astrophysics
L. Linan, F. Regnault, B. Perri, M. Brchnelova, B. Kuzma, A. Lani, S. Poedts, B. Schmieder
Summary: This paper aims to use the COCONUT coronal model to compute a detailed representation of a numerical CME at 0.1 AU based on observed magnetograms. By tracking 24 flux ropes with different initial magnetic flux, the shape and properties of the CME during the early stages of propagation were investigated. The results show that the density and magnetic field profiles at 0.1 AU are similar to observations, indicating the presence of a magnetic ejecta composed of the implemented flux rope and a sheath ahead of it. The use of COCONUT in combination with heliospheric simulations could lead to more realistic and reliable CME evolution models and predictions.
ASTRONOMY & ASTROPHYSICS
(2023)