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Nagoya university team develops 1st formula for accurate solar flare predictions

An X-ray image of a solar flare taken by the sun-observation satellite Hinode is seen in this photograph provided by the National Astronomical Observatory of Japan and the Japan Aerospace Exploration Agency (JAXA).

NAGOYA -- A research team at Nagoya University in central Japan has successfully developed a physics-based model that it says can accurately predict the location and scale of solar flares occurring on the surface of the sun, raising hope the knowledge will help avert the damage such flares can cause.

    During a solar flare, sunspots and the areas around them release energy explosively. The phenomenon produces large amounts of X-rays, which are believed to have the potential to damage satellites and cause large-scale power outages on Earth. But based on the new model's predictions, it may now be possible to avoid the adverse effects of a flare ahead of time.

    Sunspots are internally connected by lines of magnetic force with positive and negative polarities. Solar flares are said to occur when parts of the magnetic force reconnect and cause instability. Many researchers are involved with "space weather forecasts" which try to predict the effects of solar flares, but until now all they've been able to do is compare the shapes of sunspots that have produced the phenomenon to make their projections. With few recorded instances of solar flares to refer to, their accuracy was also low.

    The Nagoya University research team turned its attention to magnetic reconnections, and developed a formula that could predict solar flares by calculating what scale of reconnections is required for a solar flare to occur. The team says that by working in accordance with the formula, the location and size of a flare can be calculated. When it tested the formula on nine large solar flares recorded to have taken place in the 10 years leading to 2019, seven of their predictions reportedly matched the data from the flares that actually occurred.

    Solar flare forecasts are possible between a day and a few hours before they occur, so the team is now working with the Tokyo-based International Space Environment Service, Regional Warning Center Japan to make its findings applicable in practical settings.

    Kanya Kusano, a professor at Nagoya University involved in space-Earth environmental research, said, "This will lead to greater accuracy in predicting solar flares, which can affect our social infrastructure. We want to aim for it to be usable within one or two years."

    The team's findings were published in the online edition of U.S. journal "Science" on July 31.

    (Japanese original by Shinichiro Kawase, Nagoya News Center)

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