The recent observation of magnetic fields of a solar eruption, or Coronal Mass Ejection (CME), by Indian scientists in collaboration with international partners, shed new light on the workings of our Sun. These observations help us understand more about these solar eruptions, which can hurl a billion tons of matter at speeds of several million miles per hour into space.
Research on Solar Eruptions
Scientists from the Indian Institute of Astrophysics (IIA) located at Gauribidanur, Karnataka, embarked on an investigation revealing the mysteries of the Sun’s coronal mass ejections. They chose to focus on a particular CME that occurred on the 1st of May, 2016.
For the first time, they studied the weak thermal radio emission connected with the erupted plasma, successfully measuring the magnetic field and other physical conditions of the eruption. The IIA utilized their own radio telescopes combined with space-based telescopes capable of observing the Sun in extreme ultraviolet and white light to detect these emissions.
By examining the polarisation of these emissions, scientists were able to infer the direction the electric and magnetic components of the waves oscillate in. This innovative research was supported by the Department of Science & Technology (DST), an autonomous institute.
Understanding Coronal Mass Ejections
Coronal Mass Ejections are massive eruptions and constitute the most energetic explosions occurring within our solar system. Despite their frequency and power, the underlying cause of CMEs remains unknown, although there is consensus among astronomers that the Sun’s magnetic field plays a significant role.
These eruptions can occur anywhere on the Sun but the ones originating from regions near the centre of the visible solar surface, also known as the photosphere, are most crucial to study since they may propagate directly towards Earth.
Effects on Space Weather and Earth
When particularly strong CMEs pass the Earth, they can lead to damage to the electronics in satellites and disrupt our radio communication networks. The collision of a plasma cloud with Earth usually results in geomagnetic storms. These are significant disturbances in Earth’s magnetosphere caused by efficient energy exchange from the solar wind into the space environment surrounding Earth.
These geomagnetic storms can trigger spectacular displays of auroras, also known as northern and southern lights. These light displays are created when energy and small particles travelling down the magnetic field lines at the Earth’s poles interact with gases in the atmosphere.
Inside the Sun
The Sun is made up of several layers, each contributing to its heat and light. At the core, thermonuclear reactions generate energy creating extreme temperatures. This energy moves slowly outward through the Radiative Zone, taking more than 170,000 years to permeate this layer.
In the Convection Zone, energy continues its journey towards the surface through convection currents of heated and cooled gas. The Chromosphere, a relatively thin layer, is shaped by magnetic field lines restraining the electrically charged solar plasma. Occasionally, larger plasma features known as prominences form and extend into the Corona, sometimes ejecting material away from the Sun.
The Corona itself is comprised of ionized elements which glow in the x-ray and extreme ultraviolet wavelengths. Instrumentation in space can image the Sun’s corona at these higher energies since the photosphere is quite dim in these wavelengths. Finally, coronal streamers, tapered forms shaped by magnetic field lines, extend millions of miles into space.
An interesting feature on the Sun’s surface are sunspots, dark-looking areas that are cooler than surrounding parts.
