Using data obtained by its SDO (Solar Dynamics Observatory) space probe, NASA scientists have created a simulation of the solar magnetic field. This represents an aid in the understanding of its influence on what happens in the Sun, a series of phenomena that have important effects in the solar system. Solar explosions causing auroras are the most visible consequence but there are also other ones such as the interplanetary magnetic field and the radiation that spacecraft must go through to travel through the solar system.
The solar magnetic field is invisible but can be studied through its effects on the Sun’s plasma, the highly ionized and extremely hot gas whose movements form rings and flares in the solar corona that shine in the ultraviolet light frequencies. The magnetic effects can be measured with precision using an instrument called magnetograph, which measures magnetic fields’ strength and direction.
Scientists combine these measurements with simulations based on increasingly sophisticated models. The last simulation was called PFSS (Potential Source Surface Field) and NASA created a video that gives an idea of how it allows to accurately illustrate how magnetic fields undulates around the Sun. With these models, we can make an idea of what the magnetic field looks like in the solar corona and also on the Sun’s far side.
There are many things we don’t yet know about the solar magnetic field, for example where it’s created. We know the activity cycle that lasts about 11 years and the data accumulated through the SDO space probe and other observations now allow scientists to see the changes at magnetic level that happened in the past few years in the Sun.
The picture shows for example the changes in the Sun’s magnetic field between January 2011 and July 2014. In 2011, about three years after the minimum in its 11-year cycle, it was much more concentrated near the Sun’s poles. In 2014, it was chaotic with its “lines” tangled, optimal conditions for flares and coronal mass ejections.
The researches on the Sun’s magnetic activity will continue to understand the secrets of its magnetic field. This is crucial to predict solar activity, especially the type potentially harmful to space probes and satellites in orbit but in the worst cases even to power grids on Earth and astronauts.
