The spheromak tilting and how it affects modelling coronal mass ejections
arXiv:2111.08770 · doi:10.3847/1538-4357/ac3a73
Abstract
Spheromak type flux ropes are increasingly used for modelling coronal mass ejections (CMEs). Many models aim in accurately reconstructing the magnetic field topology of CMEs, considering its importance in assessing their impact on modern technology and human activities in space and on ground. However, so far there is little discussion about how the details of the magnetic structure of a spheromak affect its evolution through the ambient field in the modelling domain, and what impact this has on the accuracy of magnetic field topology predictions. If the spheromak has its axis of symmetry (geometric axis) at an angle with respect to the direction of the ambient field, then the spheromak starts rotating so that its symmetry axis finally aligns with the ambient field. When using the spheromak in space weather forecasting models this tilting can happen already during insertion and significantly affects the results. In this paper we highlight this issue previously not examined in the field of space weather and we estimate the angle by which the spheromak rotates under different conditions. To do this we generated simple purely radial ambient magnetic field topologies (weak/strong positive/negative) and inserted spheromaks with varying initial speed and tilt, and magnetic helicity sign. We employ different physical and geometric criteria to locate the magnetic centre of mass and axis of symmetry of the spheromak. We confirm that spheromaks rotate in all investigated conditions and their direction and angle of rotation depend on the spheromak's initial properties and ambient magnetic field strength and orientation.
arXiv commentAccepted for publication in ApJ
References in corpus (14)
- How Many CMEs Have Flux Ropes? Deciphering the Signatures of Shocks, Flux Ropes, and Prominences in Coronagraph Observations of CMEs
- Three-dimensional evolution of flux rope CMEs and its relation to the local orientation of the heliospheric current sheet
- Global Trends of CME Deflections Based on CME and Solar Parameters
- CME-CME Interactions as Sources of CME Geo-effectiveness: The Formation of the Complex Ejecta and Intense Geomagnetic Storm in Early September 2017
- Data Constrained Coronal Mass Ejections in A Global Magnetohydrodynamics Model
- Relationship between EIT Post Eruption Arcades, Coronal Mass Ejections, Coronal Neutral Line and Magnetic Clouds
- CME -- HSS interaction and characteristics tracked from Sun to Earth
- The Heliocentric Distance Where the Deflections and Rotations of Solar Coronal Mass Ejections Occur
- MHD Modeling for Formation Process of Coronal Mass Ejections: Interaction between Ejecting Flux Rope and Ambient Field
- Modelling a multi-spacecraft coronal mass ejection encounter with EUHFORIA
- Data-constrained Model for Coronal Mass Ejections Using Graduated Cylindrical Shell Method
- A Modified Spheromak Model Suitable for Coronal Mass Ejection Simulations
- Application of a Modified Spheromak Model to Simulations of Coronal Mass Ejection in the Inner Heliosphere
- Tilting Instability of Magnetically Confined Spheromaks
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- Rotation and interaction of the September 8 and 10, 2014 CMEs tested with EUHFORIA
- Self-consistent propagation of flux ropes in realistic coronal simulations
- Over-expansion of coronal mass ejections modelled using 3D MHD EUHFORIA simulations
- Modelling the interaction of Alfvénic fluctuations with coronal mass ejections in the low solar corona
- Toroidal modified Miller-Turner CME model in EUHFORIA: II. Validation and comparison with flux rope and spheromak
- Multi spacecraft study with the Icarus model: Modelling the propagation of CMEs to Mercury and Earth