doi:10.1038/nindia.2012.190 Published online 20 December 2012
Relying on observational data from a sun-facing satellite, researchers have gained new insights into how rotational motions of sunspots contribute to solar flares and coronal mass ejections (CMEs) from an active region (AR) of the Sun.
These insights are significant and useful as the flares and CMEs containing energetic charged particles escape into space and on their way to Earth could disrupt the activity of satellites, having disastrous effects on satellite-based telecommunication networks on Earth.
Sunspots and ARs are manifestation of the magnetic field generated in the Sun's interior. Recent studies have shown that rotational motions of sunspots shear and twist overlying magnetic fields, storing excess energy which, when released from the Sun's atmosphere into space, causes eruptive events like flares and CMEs. A better understanding of flares and CMEs is imperative, given their important bearings on Earth's environment.
To throw new light on how rotating sunspots influence flares and CMEs, the researchers have studied AR NOAA 11158, an active region located in the southern hemisphere of the Sun. They used observational data obtained from the the Helioseismic and Magnetic Imager and the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO), a sun-pointing NASA satellite, and the Solar Optical Telescope (SOT) onboard the Hinode, a Japanese solar satellite. The AIA captured images of the Sun's various atmospheric layers in soft X-ray, extreme ultraviolet and ultraviolet wavelengths.
The study found that AR NOAA 11158 first appeared as small pores on the solar disk in February 2011, forming bigger sunspots through the merging of small pores. Many intermittent CMEs were also launched from this AR. The researchers say that these flares and CMEs appeared to be related to the observed motions in the AR influenced and shaped by the rotating sunspots.
The authors of this work are from: Udaipur Solar Observatory, Physical Research Laboratory, Udaipur, India and Astronomy Program, and Department of Physics and Astronomy, Seoul National University, Seoul, Republic of Korea.