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Source of solar particles that threaten spaceflight and satellites is identified in the sun


Scientists have identified the source in the sun which produces solar energetic particles that threaten crewed spaceflight, near-Earth satellites and airplanes.

A team of US researchers analyzed the composition of particles that flew towards Earth in 2014 and found the same ‘fingerprint’ of plasma that is located low in the sun’s chromosphere – its second most outer layer.

The solar energetic particles are released from the sun at high speed during storms in its atmosphere and for the first time scientists have identified their source.

If these particles manage to reach Earth in high enough numbers, they could disrupt satellites and electronic infrastructure, as well as posing a possible radiation risk to astronauts and people travelling in planes when they hit.

The team behind the new study says this new information can be used to better predict when a major solar storm will hit and act faster to mitigate the risks.

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Scientists have identified the source in the sun which produces solar energetic particles that threaten crewed spaceflight, near-Earth satellites and airplanes

The discovery was made by researchers from the University of California, Los Angeles and George Mason University in Virginia.

Co-author Dr. Stephanie Yardley (UCL Mullard Space Science Laboratory, MSSL) said this is the first time the location of solar energetic particles have been traced to their original location inside the sun.

They were pinned down to plasma that was held dow low in the sun’s atmosphere by strong magnetic fields – inside the chromosphere.  

Understanding where they come from is vital, as it can provide scientists and officials with valuable seconds and minutes to prepare before they hit.  

Yardley told the BBC Today show that they can arrive within ten minutes of leaving the sun and can cause damage to astronauts, spacecraft and even airlines. 

She said: ‘They can cause damage to our spacecraft, satellite electronics, they effect any crewed spacecraft – astronauts – and even airlines as well.’

‘Essentially it effects polar or high altitude planes, so they may have to fly at lower altitude to protect from radiation or protect their electronics.’ 

A team of US researchers analyzed the composition of particles that flew towards Earth in 2014 and found the same 'fingerprint' of plasma that is located low in the sun's chromosphere

A team of US researchers analyzed the composition of particles that flew towards Earth in 2014 and found the same ‘fingerprint’ of plasma that is located low in the sun’s chromosphere

Researchers used measurements from NASA's Wind satellite, located between the sun and Earth, to analyze a series of solar energetic particle streams, each lasting at least a day, in January 2014

Researchers used measurements from NASA’s Wind satellite, located between the sun and Earth, to analyze a series of solar energetic particle streams, each lasting at least a day, in January 2014

The aim of the study is to eventually be able to create predictions to show when, where and how powerful the eruptions will be.  

Scientists have long been investigating space weather to better forecast and prepare for the potentially hazardous events.

‘We need to understand and characterize the processes that form and heat the solar atmosphere and accelerate the solar wind into the heliosphere,’ reads the study published in the Science Advances journal.

‘From a space weather perspective, we must elucidate the mechanisms that drive solar flares, coronal mass ejections (CMEs), and solar energetic particles (SEPs).’

In the study, researchers used measurements from NASA’s Wind satellite, located between the sun and Earth, to analyze a series of solar energetic particle streams, each lasting at least a day, in January 2014. 

These results (blue images)  were then compared this to spectroscopy data from the JAXA-led Hinode spacecraft, which explores the magnetic fields of the sun to uncover what powers the solar atmosphere and sparks solar eruptions

These results (blue images)  were then compared this to spectroscopy data from the JAXA-led Hinode spacecraft, which explores the magnetic fields of the sun to uncover what powers the solar atmosphere and sparks solar eruptions

WHAT IS THE SOLAR CYCLE?

The sun is a huge ball of electrically-charged hot gas that moves, generating a powerful magnetic field.

This magnetic field goes through a cycle, called the solar cycle.

Every 11 years or so, the sun’s magnetic field completely flips, meaning the sun’s north and south poles switch places. 

The solar cycle affects activity on the surface of the sun, such as sunspots which are caused by the sun’s magnetic fields. 

One way to track the solar cycle is by counting the number of sunspots.

The beginning of a solar cycle is a solar minimum, or when the sun has the least sunspots. Over time, solar activity – and the number of sunspots – increases.

The middle of the solar cycle is the solar maximum, or when the sun has the most sunspots.

As the cycle ends, it fades back to the solar minimum and then a new cycle begins.

These results were then compared this to spectroscopy data from the JAXA-led Hinode spacecraft, which explores the magnetic fields of the sun to uncover what powers the solar atmosphere and sparks solar eruptions.

The 2014 high-energy particles came for a highly active region of the sun that frequently gives off solar flares and CMEs, and an extremely strong magnetic field.

‘These energetic particles, once released, are then accelerated by eruptions that travel at a speed of a few thousand kilometers a second,’ said Yardley. 

The area, dubbed 11944, was one of the largest active regions on the Sun at the time and was visible to observers on Earth as a sunspot—a dark spot on the surface of the sun.

And this made it a prime spot for the team to investigate.

They found that the solar energetic particles measured by the Wind satellite had the same chemical signature—an abundance of silicon compared to sulfur—as plasma confined close to the top of the Sun’s chromosphere.

These locations were at the ‘footpoints’ of hot coronal loops—that is, at the bottom of loops of magnetic field and plasma extending out into the Sun’s outer atmosphere and back again.

Using a new technique, the team measured the coronal magnetic field strength at these footpoints, and found it was very high, in the region of 245 to 550 Gauss, confirming the theory that the plasma is held down in the Sun’s atmosphere by strong magnetic fields ahead of its release into space.

Lead author Dr. David Brooks (George Mason University and Honorary Associate Professor at UCL MSSL) said: ‘Our observations provide a tantalizing glimpse into where the material that produces solar energetic particles comes from in a few events from the last solar cycle.’

‘We are now starting a new solar cycle, and once it gets going we will use the same techniques to see if our results are generally true, or if these events are somehow unusual.

Yardley told Today they already send out warnings about upcoming events but they get a lot of false alerts as they are very difficult to predict.

Being able to pin down where the particles come from, throughout the sun and not just in one region, could improve the predictions and reduce false alerts.

‘The main focus is the radiation risk, we can work to reduce this to any passengers and crew  or protect astronauts, especially on longer duration flights to Mars in the future.’

HOW IS THE SOLAR WIND FORMED?

The sun and its atmosphere are made of plasma – a mix of positively and negatively charged particles which have separated at extremely high temperatures, that both carries and travels along magnetic field lines.

Material from the corona streams out into space, filling the solar system with the solar wind. 

But scientists found that as the plasma travels further away from the sun, things change. 

Views of the solar wind from NASA’s STEREO spacecraft (left) and after computer processing (right). Scientists used an algorithm to dim the appearance of bright stars and dust in images of the faint solar wind

The sun begins to lose magnetic control, forming the boundary that defines the outer corona – the very edge of the sun. 

The breakup of the rays is similar to the way water shoots out from a squirt gun.

First, the water is a smooth and unified stream, but it eventually breaks up into droplets, then smaller drops and eventually a fine, misty spray. 

A recent Nasa study captured the plasma at the same stage where a stream of water gradually disintegrates into droplets.

If charged particles from solar winds hit Earth’s magnectic field, this can cause problems for satellite and communication equipment.



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