Spectacular footage of what first appeared to be a solar eruption, but then turned out to be something else, has given scientists insight into the sun's magnetic landscape.
On September 30, 2014, a suite of NASA instruments spotted what appeared to be a solar eruption - but soon after, a serpentine structure known as a filament rose from the surface and collapsed, being shredded to pieces by invisible magnetic forces.
A study on the phenomenon revealed it was caused by a filament pushing up against a complex magnetic structure 'like two igloos smashed against each other,' which then ate away at the filament and caused chips of solar material to spray.
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Solar flares can damage satellites and have an enormous financial cost.
Astronauts are not in immediate danger because of the relatively low orbit of this manned mission.
They do have to be concerned about cumulative exposure during space walks.
The charged particles can also threaten airlines by disturbing the Earth's magnetic field.
Very large flares can even create currents within electricity grids and knock out energy supplies.
A filament is a serpentine structure consisting of dense solar material and often associated with solar eruptions
A paper on the event was published yesterday in The Astrophysical Journal.
'Each component of our observations was very important,' said Georgios Chintzoglou, lead author of the paper and a solar physicist at Lockheed Martin Solar and Astrophysics Laboratory in Palo Alto, California, and the University Corporation for Atmospheric Research in Boulder, Colorado.
'Remove one instrument, and you're basically blind.'
'In solar physics, you need to have good coverage observing multiple temperatures.'
'If you have them all, you can tell a nice story.'
The tools behind the footage include: NASA's Solar Dynamics Observatory, NASA's Interface Region Imaging Spectrograph (IRIS), JAXA/NASA's Hinode, and several ground-based telescopes in support of the launch of the NASA-funded VAULT2.0 sounding rocket.
Together, these instruments monitor the sun at different wavelengths of light, showing both the Sun's surface and lower atmosphere in a way that allows scientists to track an eruption from its onset up through the solar atmosphere.
It can also enabled them to figure out why this one ultimately faded away.
'We were expecting an eruption; this was the most active region on the Sun that day,' said Angelos Vourlidas, an astrophysicist at the Johns Hopkins University Applied Physics Laboratory and principal investigator of the VAULT2.0.
'We saw the filament lifting with IRIS, but we didn't see it erupt in SDO or in the coronagraphs. That's how we knew it failed.'
That day, IRIS and the VAULT2.0 sounding rocket - a sub-orbital rocket that orbits earth for 20 minutes, collecting data for part of its time in the atmosphere - were pointed at the aforementioned active region.
When the solar eruption was expected, they instruments instead capture the collapse.
After studying the event, they now believe the filament must have met some magnetic boundary that prevented the unstable structure from erupting.
The solar physicists used the sun's magnetic feature to understand the force, much like how scientists use topographical data to study Earth.
Since rapid releases of energy like the one that occurred are more likely where magnetic field lines are strongly distorted, Chintzoglou and his colleagues created a model that identified such locations on the Sun.
'We computed the Sun's magnetic environment by tracing millions of magnetic field lines and looking at how neighboring field lines connect and diverge,' said Antonia Savcheva, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts.
'The amount of divergence gives us a measure of the topology.'
It shows how topology shapes how solar structures evolve on the Sun's surface and what was different on that day.
When solar structures with opposite magnetic orientations collide, they explosively release magnetic energy, heat the atmosphere with a flare and erupting into space as a coronal mass ejection.
Last year, the government published a report outlining what needs to be done to prepare for 'space weather' including solar flares and coronal mass ejections (CMEs).
Solar flares and CMEs both involve gigantic explosions of energy, but while flares can last minutes to hours and can reach Earth in a matter of minutes, CMEs are intense clouds of magnetized particles hurled into space including a hot material called plasma, which takes up to three days to reach Earth.
The two phenomena can occur at the same time and the strongest flares are almost always accompanied by CMEs.
The report states: 'Space weather results from solar activity. Solar activity can produce X-rays, high energy particles and Coronal Mass Ejections of plasma.
'Where such activity is directed towards Earth there is the potential to cause wide-ranging impacts.
'These include power loss, aviation disruption, communication loss, and disturbance to (or loss) of satellite systems.'
For example, GPS systems could go down for up to three days at a time, leaving train networks and shipping badly affected.
While mobile phones and landlines are expected to be unaffected, satellite communication and high frequency radio communication used by shipping and aircraft, could also go down for several days.
Power grids could also be affected, leading to black outs in some areas.
But during the 2014 near-eruption, the filament instead pushed up against a complex magnetic structure, which then ate away at the filament and caused chips of solar material to spray, preventing an eruption.
They described it as 'like two igloos smashed against each other' with an invisible boundary, called a hyperbolic flux tube.
'The hyperbolic flux tube breaks the filament's magnetic field lines and reconnects them with those of the ambient Sun, so that the filament's magnetic energy is stripped away,' Chintzoglou said.
Scientists have speculated this can happen, but it hasn't been until now they could explain just how a magnetic boundary on the Sun is capable of halting an eruption, stripping a filament of energy until it's too weak to erupt.
'This result would have been impossible without the coordination of NASA's solar fleet in support of our rocket launch,' Vourlidas said.
This study reveals how big of a role the Sun's magnetic topology plays in whether or not an eruption can burst from the Sun, which has an effect on earth as well - these eruptions can create space weather effects around Earth.
'Most research has gone into how topology helps eruptions escape,' Chintzoglou said.
'But this tells us that apart from the eruption mechanism, we also need to consider what the nascent structure encounters in the beginning, and how it might be stopped.'