I did a winter internship in the December of 2016 at the Indian Institute of Astrophysics, Bangalore under Prof. Dipankar Banerjee, who specializes in Solar Physics. The topic I worked on was most interesting — “Estimating the arrival times of Coronal Mass Ejections (CMEs) using a Drag-Based Model (DBM)”. This was indeed an awesome experience for me and I gained a lot of knowledge and experience, not limited to just Solar Physics.
A Coronal Mass Ejection (CME), is a large eruption of plasma and magnetic ﬁeld from the Sun. It can contain a mass larger than 1013 kg, achieve a speed of several thousand kilometers per second and may span several tens of degrees of heliographic latitude and/or longitude. CMEs often (but not always) accompany Solar Flares, which are high-energy, broad-spectrum bursts of electromagnetic radiation from the Sun. The frequency of CMEs depends on the Solar Cycle, with occurrences of a couple per day during the solar maxima, and only one per couple of days during the solar minima. CMEs may erupt from any region of the corona but are more often associated with lower latitude regions, particularly near solar minimum. Only a small percentage of CMEs are directed toward the Earth, and are called Halo-CMEs or Partial Halo-CMEs, due to their halo-like appearance around the Sun as seen from instruments on Earth. CMEs can travel large distances (covering the entire Heliospheric region). Far away from the Sun, CMEs are conventionally called ICMEs (Inter-planetary CMEs).
The estimation of the arrival times of CMEs is an important issue as Earth-bound CMEs i.e. Halo-CMEs have a direct, measurable impact on human activities. Since CMEs are composed of plasma (high energy charged particles and magnetic fields), when they reach the Earth, CMEs can cause geomagnetic storms in the Earth’s magnetosphere, and the injection and interaction of charged particles with the Earth’s atmosphere. Also, associated with CMEs are Solar Flares, which are comprised of high energy radiation (X-Rays etc.). Hence, apart from producing beautiful Aurorae near the poles, Halo-CMEs can also have a lot of negative impacts on human activities, such as:
- Interference of telecommunication through phone lines and satellites.
2. Increase in radiation exposure to high-altitude and/or high-latitude aircraft ﬂiers and astronauts.
3. Increase in atmospheric drag on orbiting spacecraft, thereby reducing orbit speed (potential crash landing).
4. Interference in spacecraft circuitry.
5. Damage to spacecraft hardware (e.g. solar cells).
6. Interference/damage to ground-based micro – and nano-circuitry.
7. Unexpected current generation in power-lines, resulting in power station damage.
It is therefore essential to be able to predict the arrival of Halo-CMEs so that accurate measures can be taken to deal with the above possibilities.
The details of my work can be found in this draft report which I am attaching here: