Scientists can now predict solar flares

Scientists have unlocked the secrets of ‘doomsday’ solar storms that can cause devastation on Earth by knocking out satellites and power grids.

The dangerous flares of high-energy particles are the result of interacting magnetic structures within our star, researchers found.

The finding could take us a step closer to predicting solar storms, which can erupt from the sun at any moment.

Previous research has found that just before a solar flare, magnetic force lines from the sun’s corona – the outer layer of the star’s atmosphere – twist together and resembles a hemp rope.

These tell-tale ropes signal a solar flare is imminent and contain huge amounts of energy. 

Now, a French team led by experts at the French National Centre for Scientific Research in Paris found that ‘magnetic cages’ around the ‘rope’ control the flares.

The cages are complex structures that rise from the surface of the sun and form an invisible loop.

If the cage is strong enough, it can protect the Earth from a solar flare, but if it is too weak, the flare could devastate our planet.

‘The important point is that we got information on something we didn’t expect to be playing an important role. That was the cage above the rope,’ Dr Tahar Amari, lead author of the study, told BBC News. 

Researchers studied a major solar eruption (pictured) from 2014 via the AIA instrument of the Nasa Solar Dynamics Observatory mission. Earth was added to the image for scale

WHAT ARE SOLAR STORMS AND ARE THEY DANGEROUS?

Solar storms, or solar activity, can be divided into four main components that can have impacts on Earth:  

• Solar flares: A large explosion in the sun’s atmosphere. These flare are made of photons that travel out directly from the flare site. Solar flares impact Earth only when they occur on the side of the sun facing Earth.  
• Coronal Mass Ejections (CME’s): Large clouds of plasma and magnetic field that erupt from the sun. These clouds can erupt in any direction, and then continue on in that direction, plowing through solar wind. These clouds only cause impacts to Earth when they’re aimed at Earth. 
• High-speed solar wind streams: These come from coronal holes on the sun, which form anywhere on the sun and usually only when they are closer to the solar equator do the winds impact Earth. 
• Solar energetic particles: High-energy charged particles thought to be released primarily by shocks formed at the front of coronal mass ejections and solar flares. When a CME cloud plows through solar wind, solar energetic particles can be produced and because they are charged, they follow the magnetic field lines between the Sun and Earth. Only charged particles that follow magnetic field lines that intersect Earth will have an impact. 

While these may seem dangerous, astronauts are not in immediate danger of these phenomena because of the relatively low orbit of manned missions.

However, they do have to be concerned about cumulative exposure during space walks.

This photo shows the sun’s coronal holes in an x-ray image. The outer solar atmosphere, the corona, is structured by strong magnetic fields, which when closed can cause the atmosphere to suddenly and violently release bubbles or tongues of gas and magnetic fields called coronal mass ejections

The damage caused by solar storms 

Solar flares can damage satellites and have an enormous financial cost.

The charged particles can also threaten airlines by disturbing Earth’s magnetic field.

Very large flares can even create currents within electricity grids and knock out energy supplies.

When Coronal Mass Ejections strike Earth they cause geomagnetic storms and enhanced aurora.

They can disrupt radio waves, GPS coordinates and overload electrical systems.

A large influx of energy could flow into high voltage power grids and permanently damage transformers.

This could shut off businesses and homes around the world. 

Source: NASA – Solar Storm and Space Weather 

Pictured is a typical solar flare, with the Earth added for scale. The huge ejections of matter and charged gas from the surface of the sun are controlled by ‘ropes’ which are restrained by magnetic cages

To gain a better understanding of how these ropes caused solar eruptions, the researchers analysed a flare from 2014.

This event in 2014 was a large solar eruption that was somehow contained, and until now nobody understood how.

Using Nasa’s Solar Dynamics Observatory (SDO) spacecraft, the team analysed data from the sun’s surface to reconstruct the event. 

Computer simulations showed that the ‘rope’ had insufficient energy to completely break free from the surrounding cage.

It is the loss of the cage that is associated with a strong energy release, which can disturb communication systems.

Model of the magnetic field in the region where a major flare occurred in December 2006. It shows the presence of a magnetic rope (in grey) several hours before the flare, maintained in a state of equilibrium by magnetic loops (in orange).

Researchers modelled the magnetic rope during the flare in 2014 and saw that it was mostly ocntained. The Earth has been superimposed to illustrate the huge scale of the phenomenon

The strength of the cage limited the impact the solar flare had on Earth as it prevented a coronary mass ejection (CME) – large clouds of plasma.

Despite the worst being contained, the solar flare from October 24th 2014 still caused a strong radio blackout. 

In a separate event in 2017, a CME knocked out radio communications for one hour on the Earth’s side facing the sun, as well as low-frequency communications used in navigation. 

The rope (magenta) can becomes twisted due to the violent and sudden motion in the corona of the sun. The strength of the 2014 eruption was so great that it destroyed some of the magnetic cage (yellow) which resulted to an electronic black-out on Earth

The biggest solar flare seen for 12 years erupted from the sun in 2017, causing radio blackouts on Earth. Two high-intensity solar flares were emitted in total, both captured by Nasa’s Solar Dynamics Observatory (SDO) satellite in this animation (credit: Nasa) 

The researchers believe that understanding what leads up to a solar flare and how they are controlled can be applied to predicting future events. 

In much the same way as patterns on Earth are used to predict the weather, the authors of this study are hopeful that the ropes and cages model can be used in a similar way.

‘We’re working on using it… you have to face practical issues. One practical issue is timescale. If you want to be very fast (in predicting events), you have to accept being less accurate,’ said Dr Amari. 

The research was published this week in Nature. 

Pictured is a magnetic scan reconstruction of a region on the Sun on 24th October 2014, using NASA/SDO magnetic data and powerful models. This scan performed few minutes before the eruption, reveals a magnetic cage containing a magnetic rope