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Team title: Understanding the Onset of CMEs/Eruptive Flares

Team ID: S3-05

Team Leads:

Spiro Antiochos (NASA/GSFC, USA),

Mark Linton (Naval Research Laboratory, USA),

Keywords (impact): Electric power systems, GICs, Navigation and/or Communications, Human exploration

Keywords (Activity Type): Understanding , Modeling


The most important drivers of destructive space weather are the giant solar eruptions usually consisting of a filament ejection, an intense X-ray flare, and a fast coronal mass ejection (CME). These major eruptive events are the largest explosions in our solar system and drive space weather such as: dangerous energetic particle radiation throughout interplanetary space and in the magnetosphere, the most powerful geomagnetic storms, and ground-level electricity disruptions. Understanding the physical origin of these major eruptive events is absolutely essential for developing an eventual first-principles-based predictive capability.

Although CMEs/flares have been studied observationally and theoretically for decades, there is still no agreement on the mechanism for their onset nor on the conditions required for their occurrence. The many previous studies, however, have definitively established that a solar eruption is due to the catastrophic disruption in the force balance between the upward magnetic pressure of the highly sheared low-lying magnetic field of a filament channel and the downward magnetic tension of overlying unsheared flux. The exact nature of the filament field and the mechanism for the force balance disruption are still not understood and are topics of intense debate throughout the international solar physics community.

The over-arching objectives of this ISWAT Team are to advance our understanding of both the pre-eruption magnetic field and of the onset mechanism. 


The goals of this Team are to advance our understanding of the pre-eruption magnetic field and of the eruption onset mechanism. Since the magnetic field in the solar corona cannot be measured directly with the accuracy required for simply observing the magnetic structure and the onset mechanism, our approach is to use forward modeling: first select several best-observed events for detailed study; second, perform the most comprehensive calculations possible for filament formation and eruption onset using the various theories proposed for these processes; finally compare the results with the actual events to determine which of the theories is most likely to be valid. 

As a result of the decades of previous studies, the number of viable theories is actually quite limited. Only three models are currently being studied for filament channel formation: flux emergence, flux cancellation, and helicity condensation. The numbers of models for the onset mechanism is even smaller; there are basically only two physically distinct theories: an ideal instability and closely related loss of equilibrium due to the torus/kink instability or magnetic reconnection as in the breakout model. 

Definitive progress on understanding, therefore, requires expertise across all these models and on observations of CMEs/flares. This ISWAT Team will combine such experts from around the world in order to perform the most effective possible forward modelling. The Team will select the events, perform the simulations for the various theories, and then test against data. We expect the results to deliver a major advance in understanding solar eruptions

Clusters with overlapping topics:

H2: CME structure, evolution and propagation through heliosphere

Action topics:

Understanding processes responsible for the occurrence of impulsive events,

Understanding and classification of pre-eruption configurations,

Modeling of CME initiation

Links to external websites: 


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