Radio waves

Indian scientists use radio waves to gain rare insight into the Sun’s interior

Months after Chandrayaan-2 examined the inner layers of the Sun, Indian scientists measured the magnetic field of an eruption in the Sun’s atmosphere. The team collaborated with international researchers to get a rare peek inside the Sun and study the inner workings of the brightest star in our solar system.

Scientists at the Indian Institute of Astrophysics (IIA) studied for the first time the low thermal radio emission associated with erupting plasma, measuring the magnetic field and other physical conditions of the eruption. The team studied plasma from the coronal mass ejection (CME) that occurred on May 1, 2016.

Coronal mass ejection is one of the largest eruptions on the surface of the Sun which can hold a billion tons of matter accelerated to millions of miles per hour in space. This solar material flows through the interplanetary medium, impacting any planet or spacecraft in its path. When a very powerful CME passes in front of Earth, it can damage the electronics of our satellites and disrupt radio communication networks on Earth.

The study published in the Geophysical Research Letters indicates that the coronal mass ejection was due to activity on the other side of the Sun, but near its limb. This made it possible to observe the weak thermal radio emission emerging from the CME and, therefore, to directly estimate the electron density, mass and magnetic field strength of the plasma.

The weather beat has become the biggest concern of astronomers around the world as humans strive to become interplanetary species. (File photo)

The emissions were detected using IIA radio telescopes in Gauribidanur, Karnataka, as well as a few space telescopes that observed the Sun in extreme ultraviolet and white light. This allowed the researchers to detect a much weaker radio emission called thermal radiation (or blackbody) from the plume of gas that was ejected into the CME. They were also able to measure the polarization of this emission, which is indicative of the direction in which the electric and magnetic components of the waves oscillate.

“Although CMEs can occur anywhere on the Sun, it is primarily those that originate from regions near the center of the visible solar surface (called the photosphere) like the one we studied that are important to us because they can propagate directly to Earth. “said R. Ramesh, professor at IIA Bangalore and lead author of the article.

Scientists have long studied solar flares to understand how they occur so that they can be tracked effectively and action can be taken in advance to protect critical assets on Earth that might be affected. Space weather has become the primary concern of astronomers around the world as humans strive to become interplanetary species. Tracking the evolution of radiation beyond Earth is mission critical for cargo ships and astronauts operating in space.

“These CMEs are usually studied in visible light, but because the Sun’s disk is much brighter, we can only detect and track these CMEs when they have traveled beyond the Sun’s surface. However, radio observations of thermal emission, as in our study, allow us to study CMEs directly from the surface itself, ”said A. Kumari, co-author of the study.

A recent study by Sangeetha Abdu Jyothi of the University of California on how solar storms can be damaging to the internet around the world pointed out that such a storm has sufficient force to cause catastrophic disruption over the course of the next decade.