New Mar 11 (IANS): Indian researchers have developed a simple technique of separating the constant background of the Solar Colona and revealing the dynamic corona.
The technique has been developed jointly by the Aryabhatta Research Institute and the Indian Institute of Astrophysics.
"The simple approach of subtracting the constant background can improve efficiency of identification of Coronal Mass Ejections (CME) -- events in which a large cloud of energetic and highly magnetised plasma erupts from the solar corona into space, causing radio and magnetic disturbances on the Earth. It can also give a clear picture of the characteristics of CMEs and make their study easier," said the team of scientist involed in the research.
Coronal Mass Ejections (CMEs) are large expulsions of plasma and magnetic field from the Sun's corona. They can eject billions of tonnes of coronal material and carry an embedded magnetic field (frozen in flux) that is stronger than the background solar wind interplanetary magnetic field (IMF) strength.
CMEs travel outward from the Sun at speeds ranging from slower than 250 km per second (km/s) to as fast as near 3,000 km/s. The fastest Earth-directed CMEs can reach our planet in as little as 15-18 hours. Slower CMEs can take several days to arrive. They expand in size as they propagate away from the Sun and larger CMEs can reach a size comprising nearly a quarter of the space between Earth and the Sun by the time it reaches our planet.
CMEs are dynamic structures in the Solar Corona and are capable of driving the Space Weather in near-Earth space. It becomes imperative to separate such structures and visually or automatically identify the CMEs through the radial distances in the images taken using coronagraphs.
The density of the outermost layer of the atmosphere of the Sun - Corona - decreases with distance radially outwards. As the intensity of the corona observed in white light depends on the density of particles in the atmosphere, it decreases exponentially. If the contrast between the constant corona and transient CMEs is not high, detection of CMEs becomes a challenge.
The new method was developed by Ritesh Patel, Vaibhav Pant and Dipankar Banerjee from the Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital, along with Satabdwa Majumdar from the Indian Institute of Astrophysics (IIA), Bengaluru, autonomous institutes under the Department of Science and Technology, Government of India.
The research has been accepted for publication in the Solar Physics journal.