At the outer edges of the solar atmosphere, the temperature rises to several million degrees Celsius
No one will be surprised if he finds out that the Sun is an incredibly hot object. On its surface, the temperature reaches several thousand degrees Celsius. It usually seems that, according to the principle of the action of fire, the temperature will fall with distance to the surface. However, at the outermost part of the solar atmosphere, heating is rapidly increasing to several million degrees. Only now scientists believe that they are getting close to solving this phenomenon.
This is Dr. Sven Wedemeyer of the University of Oslo (Norway), working on the SolarALMA project. There are many theories about why such a huge amount of heat is concentrated on the crown. Some people think that heat is transferred there by acoustic waves. Others claim that the heat is generated by overlapping magnetic field lines. But which option is correct?
ALMA is represented by 66 radio antennas set at distances of 16 km. This array is able to study different wavelengths of the Sun (like different colors in visible color) with unprecedented resolution. Each color gives an idea of the structure of the star at different depths.
The main task is to create computational tools for converting the initial information of ALMA into a three-dimensional temperature map. Previously, such devices have already been manufactured to study nebulae and other astrophysical objects. But they need to engage in observation for a long time period.
The SolarALMA project creates thermal solar maps to better understand the principle of crown heating
The sun is constantly changing, so creating tools is much more difficult. However, Wedemeyer talks about the importance of such a study, since it is possible to generate not only solar images, but also entire films.
The first images will be created based on the data of December 2016 and April 2017. It’s too early to talk about a breakthrough, but the scientist assures that he will come. In addition to ALMA, the Solar Dynamics Observatory and STEREO are also used.
Errors and Problems
The difficulty with observations is that they cannot be easily compared with the computational models of the Sun. For example, a review can register the radiation intensity, and the computational model functions from the standpoint of temperature and density.
Therefore, we created the project CORONALDOLLS, trying to bridge the gap between these parameters. The main goal is to identify unique signatures in computational models that, when confirmed, will serve as proof of a specific heating mechanism.
Finding a control signature is not easy, but waves in the solar atmosphere can convey information about the stellar structure, as earthquakes on Earth do.