Russian Radio Astronomers Discover a Method for Predicting Solar Flares

Researchers from HSE in Nizhny Novgorod and the Pulkovo Astronomical Observatory (CAO RAS) examined data on microwave emissions from several active solar regions. This observational data was recorded with a 2D spatial resolution using the Nobeyama Radioheliograph. Each active region where a flare had previously occurred was divided into sections, and their respective microwave emissions were compared.  Astronomers discovered that a few hours prior to a flare, there was an increase in oscillations in the region with the highest observed brightness of the microwave emission during the flare. This method can potentially be used to achieve more accurate predictions of severe solar flares. The study has been published in Geomagnetism and Aeronomy.

Solar flares are eruptions of explosive energy in the Sun's atmosphere. A strong solar flare can release more energy than the entire energy industry on Earth produces over several years.

Occasionally, these powerful flares are accompanied by a coronal mass ejection (CME) — an eruption of billions of tons of matter from the outer layers of the Sun, traveling at speeds ranging from 10km/s to more than 3000 km/s. Emissions directed towards the Earth can trigger magnetic storms which, at times, can cause failure in satellite operations and electrical networks and also impact the well-being of weather-sensitive individuals.

Radio astronomers are constantly monitoring solar activity and working to devise new and better methods for predicting hazardous magnetic storms. Researchers from HSE and the CAO RAS, having examined the data from the Nobeyama Radioheliograph, were able to describe those signs which can be predict solar flares.

Our colleagues from NIRFI had conducted similar studies previously, but using smaller telescopes. In contrast, we have analysed the data from the Nobeyama Radioheliograph with 2D resolution, allowing us to precisely determine the regions on the Sun where microwave radiation fluctuations occur. The Nobeyama Radioheliograph provided observational data until 2020 and operated at frequencies of 17 and 34 GHz. We will receive new data from the upgraded Siberian Radioheliograph, which operates over a wide frequency range of 3 to 24 GHz.

Irina Bakunina <
Candidate of Sciences, Associate Professor, Department of Mathematical Economics, HSE Campus in Nizhny Novgorod

The researchers analysed data from three active solar regions:  NOAA AR 11283, NOAA AR 11302, and NOAA AR 11515. The radio images of the regions were divided into six sections, and the microwave emission fluctuations from each section were compared.

The areas exhibiting the most intense microwave emission fluctuations prior to the flare were subsequently the brightest during the flare. The researchers explain this phenomenon by noting that the fluctuations of microwave emission reflect the dynamic processes occurring in the active regions before the flares.

We believe that analysing microwave emission fluctuations can contribute to a better understanding of the mechanisms behind flare occurrences and enhance the criteria for predicting them. We plan to continue our in-depth study of the mechanism behind solar flares accompanied by coronal mass ejections, and will soon publish a study on using algorithms for the 3D extrapolation of magnetic fields in active regions to elucidate the role of magnetic bundles in flares of different types.

Irina Bakunina <
Candidate of Sciences, Associate Professor, Department of Mathematical Economics, HSE Campus in Nizhny Novgorod

IQ

August 18, 2023