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Aims. Working towards improved space weather predictions, we aim to quantify how the critical height at which the torus instability drives coronal mass ejections (CMEs) varies over time in a sample of solar active regions. Methods. We model…

Solar and Stellar Astrophysics · Physics 2022-09-07 Alexander W. James , David R. Williams , Jennifer O'Kane

A local magnetic equilibrium solution is sought around the magnetic axis in order to identify the key parameters defining the magnetic-surface's up-down asymmetry in the core of tokamak plasmas. The asymmetry is found to be determined…

Plasma Physics · Physics 2014-10-08 Paulo Rodrigues , Nuno F. Loureiro , Justin Ball , Felix I. Parra

Coronal mass ejections (CMEs) are solar eruptions that involve large-scale changes to the magnetic topology of an active region. There exists a range of models for CME onset which are based on twisted or sheared magnetic field above a…

Solar and Stellar Astrophysics · Physics 2024-09-12 Aslam Ottupara , David MacTaggart , Tom Williams , Lyndsay Fletcher , Paolo Romano

Studying the ambient solar wind, a continuous pressure-driven plasma flow emanating from our Sun, is an important component of space weather research. The ambient solar wind flows in interplanetary space determine how solar storms evolve…

The near-Sun kinematics of coronal mass ejections (CMEs) determine the severity and arrival time of associated geomagnetic storms. We investigate the relationship between the deprojected speed and kinetic energy of CMEs and magnetic…

Solar and Stellar Astrophysics · Physics 2018-09-19 Sanchita Pal , Dibyendu Nandy , Nandita Srivastava , Nat Gopalswamy , Suman Panda

A fundamental property of coronal mass ejections (CMEs) is their radial expansion, which determines the increase in the CME radial size and the decrease in the CME magnetic field strength as the CME propagates. CME radial expansion can be…

Solar and Stellar Astrophysics · Physics 2023-07-19 Bin Zhuang , Noé Lugaz , Nada Al-Haddad , Réka M. Winslow , Camilla Scolini , Charles J. Farrugia , Antoinette B. Galvin

Interplanetary coronal mass ejections (ICMEs) are a significant feature of the heliospheric environment and the primary cause of adverse space weather at the Earth. ICME propagation, and the evolution of ICME magnetic field structure during…

Space Physics · Physics 2019-05-20 S. W. Good , E. K. J. Kilpua , A. T. LaMoury , R. J. Forsyth , J. P. Eastwood , C. Möstl

A key aim in space weather research is to be able to use remote-sensing observations of the solar atmosphere to extend the lead time of predicting the geoeffectiveness of a coronal mass ejection (CME). In order to achieve this, the magnetic…

Solar and Stellar Astrophysics · Physics 2017-02-16 Erika Palmerio , Emilia K. J. Kilpua , Alexander W. James , Lucie M. Green , Jens Pomoell , Alexey Isavnin , Gherardo Valori

Understanding the trajectory of a coronal mass ejection (CME), including any deflection from a radial path, and the orientation of its magnetic field is essential for space weather predictions. Kay et al. (2015b) developed a model,…

Solar and Stellar Astrophysics · Physics 2015-10-07 C. Kay , M. Opher

Coronal Mass Ejections (CMEs) contributes to the perturbation of solar wind in the heliosphere. Thus, depending on the different phases of the solar cycle and the rate of CME occurrence, contribution of CMEs to solar wind parameters near…

Solar and Stellar Astrophysics · Physics 2019-01-30 Wageesh Mishra , Nandita Srivastava , Zavkiddin Mirtoshev , Yuming Wang

Our aim is to study the role of gravitational stratification on the propagation of CMEs. In particular, we assess how it influences the speed and shape of CMEs and under what conditions the flux rope ejection becomes a CME or when it is…

Space Physics · Physics 2013-10-28 Paolo Pagano , Duncan H. Mackay , Stefaan Poedts

The solar wind, when measured close to 1 au, is found to flow mostly radially outward. There are, however, periods when the flow makes angles up to 15$^\circ$ away from the radial direction, both in the east-west and north-south directions.…

Solar and Stellar Astrophysics · Physics 2022-06-01 N. Al-Haddad , A. B. Galvin , N. Lugaz , C. J. Farrugia , W. Yu

We investigate the evolution of both normal and inverse CMEs ejected at different initial velocities, and observe the effect of the background wind density and their magnetic polarity on their evolution up to 1 AU. We performed 2.5D…

Solar and Stellar Astrophysics · Physics 2019-10-11 S. Hosteaux , E. Chané , S. Poedts

Motivated by the need to improve the ability to forecast whether a certain coronal mass ejection (CME) is to impact Earth, and by the insufficiency of statistical studies that analyze the whole erupting system with the focus on the…

Solar and Stellar Astrophysics · Physics 2020-10-21 M. V. Sieyra , M. Cécere , H. Cremades , F. A. Iglesias , A. Sahade , M. Mierla , G. Stenborg , A. Costa , M. West , E. D'Huys

Model stellar atmospheres are fundamental tools for understanding stellar observations from interferometry, microlensing, eclipsing binaries and planetary transits. However, the calculations also include assumptions, such as the geometry of…

Solar and Stellar Astrophysics · Physics 2015-06-15 Hilding R. Neilson , John B. Lester

The NASA STEREO mission opened up the possibility to forecast the arrival times, speeds and directions of solar transients from outside the Sun-Earth line. In particular, we are interested in predicting potentially geo-effective…

Solar and Stellar Astrophysics · Physics 2015-06-04 Christian Möstl , Jackie A. Davies

Although all coronal mass ejections (CMEs) that propagate into the heliosphere should contain a magnetic flux rope (MFR) component, the majority do not exhibit the expected white-light MFR morphology of a leading edge plus cavity. This…

Solar and Stellar Astrophysics · Physics 2025-06-11 Cecilia Mac Cormack , Abril Sahade , Angelos Vourlidas , Phillip Hess , Robin Colaninno , Teresa Nieves-Chinchilla

Due to projection effects, coronagraphic observations cannot uniquely determine parameters relevant to the geoeffectiveness of CMEs, such as the true propagation speed, width, or source location. The Cone Model for Coronal Mass Ejections…

Astrophysics · Physics 2008-11-26 G. Michalek

Coronal mass ejections (CMEs) are large-scale ejections of magnetized plasma from the Sun and are associated with the most extreme space weather events. The geoeffectiveness of a CME is primarily determined by the southward component of its…

Solar and Stellar Astrophysics · Physics 2024-07-09 Devojyoti Kansabanik , Angelos Voulidas

Modeling of transient events in the solar atmosphere requires the confluence of 3 critical elements: (1) model sophistication, (2) data availability, and (3) data assimilation. This white paper describes required advances that will enable…

Instrumentation and Methods for Astrophysics · Physics 2023-01-02 M. Rempel , Y. Fan , M. Dikpati , A. Malanushenko , M. D. Kazachenko , M. C. M. Cheung , G. Chintzoglou , X. Sun , G. H. Fisher , T. Y. Chen