![\"Overview](\"https:\/\/cdn.sci.news\/images\/enlarge13\/image_14501e-Solar-Flare.jpg\")
<\/a><\/p>\nOverview of the impulsive phase of an M-class solar flare, observed by ESA\u2019s Solar Orbiter. Image credit: ESA \/ Solar Orbiter \/ Chitta et al., doi: 10.1051\/0004-6361\/202557253.<\/p>\n
Solar flares are powerful explosions produced by the Sun.<\/p>\n
They occur when energy stored in tangled magnetic fields is suddenly released through a process described as \u2018reconnection.\u2019<\/p>\n
In a matter of minutes, criss-crossing magnetic field lines of opposite direction break and then reconnect.<\/p>\n
The newly-reconnected field lines can quickly heat up and accelerate million-degree plasma, and even high-energy particles, away from the reconnection site, potentially creating a solar flare.<\/p>\n
The most powerful flares may start a chain of reactions that lead to geomagnetic storms on Earth, perhaps triggering radio blackouts, which is why it is so important to monitor and understand them.<\/p>\n
But the fine-grained details of how exactly this humungous amount of energy is released so rapidly has remained poorly understood.<\/p>\n
The unprecedented set of new Solar Orbiter observations \u2014 from four of the mission\u2019s instruments working in complement to provide the most complete picture of a solar flare ever made \u2014 finally has a compelling answer.<\/p>\n
High-resolution imagery from Solar Orbiter\u2019s Extreme Ultraviolet Imager (EUI) zoomed in to features just a few hundred km across in the Sun\u2019s outer atmosphere (its corona), capturing changes every two seconds.<\/p>\n
Three other instruments \u2014 SPICE, STIX and PHI \u2014 analyzed a range of depths and temperature regimes, from the corona down to the Sun\u2019s visible surface, or photosphere.<\/p>\n
\u201cWe were really very lucky to witness the precursor events of this large flare in such beautiful detail,\u201d said Dr. Pradeep Chitta, an astronomer at the Max Planck Institute for Solar System Research.<\/p>\n
\u201cSuch detailed high-cadence observations of a flare are not possible all the time because of the limited observational windows and because data like these take up so much memory space on the spacecraft\u2019s onboard computer.\u201d<\/p>\n
\u201cWe really were in the right place at the right time to catch the fine details of this flare.\u201d<\/p>\n
The Solar Orbiter observations revealed a comprehensive picture of the central engine of the pre-flare and impulsive phases of a solar flare in the form of a magnetic avalanche.<\/p>\n
\u201cWe saw ribbon-like features moving extremely quickly down through the Sun\u2019s atmosphere, even before the main episode of the flare,\u201d Dr. Chitta said.<\/p>\n
\u201cThese streams of \u2018raining plasma blobs\u2019 are signatures of energy deposition, which get stronger and stronger as the flare progresses.\u201d<\/p>\n
\u201cEven after the flare subsides, the rain continues for some time.\u201d<\/p>\n
\u201cIt\u2019s the first time we see this at this level of spatial and temporal detail in the solar corona.\u201d<\/p>\n
\u201cWe didn\u2019t expect that the avalanche process could lead to such high energy particles.\u201d<\/p>\n
\u201cWe still have a lot to explore in this process, but that would need even higher resolution X-ray imagery from future missions to really disentangle.\u201d<\/p>\n
\u201cThis is one of the most exciting results from Solar Orbiter so far,\u201d said ESA\u2019s Solar Orbiter co-project scientist Dr. Miho Janvie.<\/p>\n
\u201cSolar Orbiter\u2019s observations unveil the central engine of a flare and emphasize the crucial role of an avalanche-like magnetic energy release mechanism at work.\u201d<\/p>\n
\u201cAn interesting prospect is whether this mechanism happens in all flares, and on other flaring stars.\u201d<\/p>\n