Coronal Mass Ejections (CMEs) are large expulsions of plasma and magnetic field from the Sun’s corona. They eject several tons of coronal material and carry an embedded magnetic field, stronger than the background solar wind.
To study the solar atmosphere dynamics using coronagraph images, it is essential to visualize the structures. Although, the radial gradient in the intensity of the corona makes it challenging to observe the structures with the same brightness and contrast in the images.
To address this issue, Indian scientists have developed a simple technique of separating the constant background of the Solar Corona and revealing the dynamic corona. Their technique- known as Simple Radial Gradient Filter (SiRGraF), can separate the background revealing the dynamic corona.
The method involves subtracting constant background, thereby bringing out the transient corona. Later, dividing the result by an azimuthally uniform background reduces the radial decrease in intensity. Combining these two steps allows us to identify the structures such as CMEs throughout the field of view of the coronagraph images.
This method was developed by Mr. Ritesh Patel, Dr. Vaibhav Pant, and Prof. Dipankar Banerjee from Aryabhatta Research Institute of Observational Sciences (ARIES).
- Patel, R., Majumdar, S., Pant, V. et al. A Simple Radial Gradient Filter for Batch-Processing of Coronagraph Images. Sol Phys 297, 27 (2022). DOI: 10.1007/s11207-022-01957-y