Focus: GS-III Science and Technology
- The Sun is our closest star and we have been studying it for a long time, yet, it has many associated puzzles that are unexplained.
- A significant advancement has been made by an international team of solar physicists who have measured the global magnetic field of the Sun’s corona, or outer atmosphere, for the very first time.
India’s first solar mission, Aditya-L1 satellite will aim to measure the solar coronal magnetic fields regularly.
The solar puzzles
There are two main puzzles about the Sun which this advancement will help address:
- Coronal heating problem
- Mechanisms of eruptions of the Sun
Coronal Heating Problem
- Though the core of the Sun is at a temperature of about 15 million degrees, its outer layer, the photosphere is a mere 5700 degrees hot.
- However, its corona or outer atmosphere, which stretches up to several million kilometres beyond its surface, is much, much hotter than the surface (reaching temperatures of one million degrees or more).
Mechanisms of eruptions of the Sun
- Solar flares and coronal mass ejections (eruptions of the Sun) are driven by magnetic reconnections happening in the Sun’s corona.
- Magnetic reconnection is a process where oppositely polarity magnetic field lines connect and some of the magnetic energy is converted to heat energy and also kinetic energy which leads to the generation of heating, solar flares, solar jets, etc.
- The team used a technique known as coronal seismology or magnetoseismology to measure the coronal magnetic field which has been known for a few decades.
- This method requires the measurement of the properties of magnetohydrodynamic (MHD) waves and the density of the corona simultaneously.
- The team used the improved measurements of the Coronal Multi-channel Polarimeter (CoMP) and advanced data analysis to measure the coronal magnetic field.
- It is very important to measure the corneal magnetic fields regularly since the solar corona is highly dynamic and varies within seconds to a minute time scale.
-Source: The Hindu