This year marks a peak year in the solar activity cycle, which repeats every 11 years. The sun's magnetic field strengthens around the peak, and sunspot activity becomes vigorous. Domestic researchers announced the results of their analysis of the powerful solar geomagnetic storm phenomena that occurred last year.
The Korea Astronomy and Space Science Institute (KASI) Solar Space Environment Group observed the G5-class geomagnetic storm that occurred from May 10 to 12 of last year through the latest domestic and international satellites and ground observation systems, and comprehensively analyzed its causes and physical mechanisms, with the results published on the 13th. The research findings were also published in the Journal of the Korean Space Science Society.
A geomagnetic storm is a phenomenon where a strong solar storm from the sun reaches Earth and disrupts the Earth's magnetic field. Geomagnetic storms are categorized by the National Oceanic and Atmospheric Administration (NOAA) Space Weather Prediction Center (SWPC) into grades ranging from G1 (weak) to G5 (severe). In May of last year, the strongest G5 geomagnetic storm in 21 years occurred, and another G4 geomagnetic storm took place on January 1 of this year.
According to the researchers' analysis, the geomagnetic storm was confirmed to have originated from complex magnetic field configurations of 13664 and 13668, accompanied by X-class flares and several coronal mass ejections (CMEs). X-class flares are the strongest category of 'solar flares,' which are bursts of light and energy from the stellar surface. Coronal mass ejections refer to the clouds of gas and plasma explosively expelled from the sun's outer atmosphere, the corona, into interplanetary space.
In particular, the X2.2-class flare that appeared on May 9 of last year triggered a major CME, which combined with previously occurred CMEs, leading to a powerful solar wind reaching Earth's orbit. Consequently, the Earth's magnetosphere was strongly compressed, resulting in a powerful magnetic reconnection between the interplanetary magnetic field heading south and the Earth's magnetic field. As a result, there was an increase in energy influx into the Earth's high-latitude upper atmosphere, heating the Earth's thermosphere and causing changes in the electron density of the ionosphere. The researchers confirmed auroras using the all-sky camera operated at the Antarctic Jangbogo Research Station and also monitored changes in cosmic radiation influx through the neutron monitor installed in Geochang's Gamak Mountain.
Kwak Young-sil, a senior researcher at KASI, noted, 'By analyzing the G5-class geomagnetic storm from multiple angles, we have gained a better understanding of the interactions between the sun and the Earth's magnetosphere, as well as their global impacts and mechanisms.' She remarked that this will aid in understanding space weather changes during this year's solar activity peak and will serve as a good foundational resource for future preparations.
Meanwhile, KASI will hold a solar space environment workshop and winter school from January 13 to 15 in cooperation with the Korean Space Science Society and the Korean Astronomical Society. Over 100 domestic space weather researchers will gather at KASI's headquarters to present the latest developments. This event will share continuous monitoring of solar activity and space weather changes using advanced ground and space-based observation equipment and data analysis techniques, while exchanging methods to enhance the reliability of space weather forecasting.
Reference Materials
Journal of the Korean Space Science Society (2024), DOI: https://doi.org/10.5140/JASS.2024.41.3.171