The solar corona is the outermost layer of the Sun's atmosphere that consists of hot, diffused and highly ionised plasma. However, it remains hidden from our sight due to the bright light of the Sun's surface.
As the region is difficult to visualise without specific instruments, its magnetic field has been difficult to measure with observations. The magnetic field is important as it causes many of the physical properties of the sun.
According to a news release published by the Northumbria University on 19 August, the magnetic field leads to events such as the 11-year solar cycle, the solar eruptions, and also the heating up of the hot gas in the solar corona to millions of degrees Celsius.
A team of international solar physicists has now managed to map the global magnetic field of the solar corona for the first time. They used a specialised instrument called a ‘coronagraph’ or the ‘near-infrared imaging spectroscopy’ to block out the sun’s bright disk to measure the “speed and intensity of waves rippling through coronal plasma”, reported Science News. The report added that the instrument was made in 2016 and it allowed physicists to look at the whole corona at once.
The team consisted of researchers from Northumbria University, Newcastle, Peking University, China, and National Center for Atmospheric Research (NCAR), USA. They used the device to determine the “electron density and magnetohydrodynamic wave speed” in the corona. By combining these measurements, the abstract of the study said, the team was successful in deriving maps of the magnetic field throughout the “entire observable corona”. The study was published in the journal Science on 7 August.
According to Jenna Samra of the Smithsonian Astrophysical Observatory in Cambridge, making global maps of the coronal magnetic field strength is going to allow researchers to “eventually get better predictions of space weather events”.
