Towards a better prediction of solar eruptions

February 07, 2018

Just one phenomenon may underlie all solar eruptions, according to researchers from the CNRS, École Polytechnique, CEA and INRIA[1] in an article featured on the cover of the February 8 issue of Nature magazine. They have identified the presence of a confining 'cage' in which a magnetic rope[2] forms, causing solar eruptions. It is the resistance of this cage to the attack of the rope that determines the power and type of the upcoming flare. This work has enabled the scientists to develop a model capable of predicting the maximum energy that can be released during a solar flare, which could have potentially devastating consequences for the Earth.

Just as on Earth, storms and hurricanes sweep through the atmosphere of the Sun. These phenomena are caused by a sudden, violent reconfiguration of the solar magnetic field, and are characterized by an intense release of energy in the form of light and particle emissions and, sometimes, by the ejection of a bubble of plasma. Studying these phenomena, which take place in the corona (the outermost region of the Sun), will enable scientists to develop forecasting models, just as they do for the Earth's weather. This should limit our technological vulnerability to solar eruptions, which can impact a number of sectors such as electricity distribution, GPS and communications systems.

In 2014, researchers[3] showed that a characteristic structure, an entanglement of magnetic force lines twisted together like a hemp rope, gradually appears in the days preceding a solar flare. However, until recently then they had only observed this rope in eruptions that ejected bubbles of plasma. In this new study, the researchers studied other types of flare, the models of which are still being debated, by undertaking a more thorough analysis of the solar corona, a region where the Sun's atmosphere is so thin and hot that it is difficult to measure the solar magnetic field there. They did this by measuring stronger magnetic field at the surface of the Sun, and then using these data to reconstruct what was happening in the solar corona[4].

They applied this method to a major flare that developed over a few hours on October 24, 2014. They showed that, in the hours before the eruption, the evolving rope was confined within a multilayer magnetic 'cage'. Using evolutionary models running on supercomputer, they showed that the rope had insufficient energy to break through all the layers of the cage, making the ejection of a magnetic bubble impossible. Despite this, the high twist of the rope triggered an instability and the partial destruction of the cage, causing a powerful emission of radiation that led to disruptions on Earth.

Thanks to their method, which makes it possible to monitor the processes taking place in the last few hours leading up to a flare, the researchers have developed a model able to predict the maximum energy that can be released from the region of the Sun concerned. The model showed that for the 2014 eruption, a huge ejection of plasma would have occurred if the cage had been less resistant. This work demonstrates the crucial role played by the magnetic 'cage-rope' duo in controlling solar eruptions, as well as being a new step towards early prediction of such eruptions, which will have potentially significant societal impacts.
-end-
[1] At the Centre de Physique Théorique (CNRS/École Polytechnique/), the Laboratoire d'Astrophysique, Instrumentation, Modélisation (CNRS/CEA/Université Paris Diderot), the Laboratoire de Physique Théorique de la Matière Condensée (CNRS/Sorbonne Université) and the Gamma3 team at INRIA.

[2] See the press release: 'Understanding and predicting solar eruptions': http://www2.cnrs.fr/sites/en/fichier/cp_eruption_solaire_vfinale_en.pdf

[3] See footnote 2.

[4] The data was taken from observation of the Sun's surface by NASA's Solar Dynamic Observatory (SDO) mission. The numerical models of the magnetic fields were obtained using supercomputers at IDRIS/CINES and the École Polytechnique.

CNRS

Related Solar Flare Articles from Brightsurf:

Researchers offer unprecedented look into 'central engine' powering a solar flare
In a study published in Nature Astronomy, an international team of researchers has presented a new, detailed look inside the ''central engine'' of a large solar flare accompanied by a powerful eruption by the Owens Valley Solar Array -- a solar radio telescope facility operated by New Jersey Institute of Technology's Center for Solar-Terrestrial Research.

Researchers turn algae leftovers into renewable products with flare
Researchers take waste products from algae-based omega-3 oil production and convert them into valuable and renewable polyurethane foams with a range of of commercial applications -- from flip-flops and running shoe soles to mattresses and yoga mats.

Solar wind samples suggest new physics of massive solar ejections
A new study led by the University of Hawai'i (UH) at Mānoa has helped refine understanding of the amount of hydrogen, helium and other elements present in violent outbursts from the Sun, and other types of solar 'wind,' a stream of ionized atoms ejected from the Sun.

NJIT scientists measure the evolving energy of a solar flare's explosive first minutes
In 2017, a massive new region of magnetic field erupted on the sun's surface next to an existing sunspot.

Caught in the act: MeerKAT telescope spies stellar flare
The MeerKAT radio telescope in the Northern Cape of South Africa has discovered an object which rapidly brightened by more than a factor of three over a period of three weeks.

When tempers flare, nurses' injuries could rise
A new study by researchers at Michigan State University and Portland State University has found that when there's an imbalance in support among nurses at work, tempers flare and risk of injuries can go up.

From emergence to eruption: Comprehensive model captures life of a solar flare
A team of scientists has, for the first time, used a single, cohesive computer model to simulate the entire life cycle of a solar flare: from the buildup of energy thousands of kilometers below the solar surface, to the emergence of tangled magnetic field lines, to the explosive release of energy in a brilliant flash.

Smaller, more frequent eruptions affect volcanic flare-ups
Eruption patterns in a New Zealand volcanic system reveal how the movement of magma rising through the crust leads to smaller, more frequent eruptions.

Flare-responsive hydrogel developed to treat arthritis
BWH bioengineers and physicians team up to develop a better delivery system for getting anti-inflammatory therapies to the sites where they are needed most.

Powerful flare from star Proxima Centauri detected with ALMA
Using data from ALMA, a team of astronomers discovered that a powerful stellar flare erupted from Proxima Centauri last March.

Read More: Solar Flare News and Solar Flare Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.