One of the most characteristic images of the Sun is the spicules , jets of plasma that shoot out from its surface, giving the star king the impression that it is glowing . Now, a group of scientists has found the reason for these spicules , which are formed by the interaction between the Sun’s magnetic fields and the partially ionized gas in its atmosphere.
The work has been published in the journal Science and, in addition to solving this mystery, which had not been solved for more than a century, it could help explain the curious fact that the surface of the Sun – also known as the corona – is much hotter than its inner layers.
Thousands of solar spicules are launched every day into space at a speed of 100 kilometers per second from the surface of the Sun, a phenomenon whose origin was, to date, unknown. Now scientists know that these plasma jets are produced “by a chain of events”, which seems to be keyed in neutral particles . As explained by the main author of the study, the Spanish Juan Martínez-Sykora, in statements to the Sinc agency: “What triggers the process is the ‘release’ of the tension of the magnetic field or in the lower part of the solar atmosphere ( the chromosphere), a tension that is generated near the surface of the Sun by the random movements of boiling “.
These neutral particles, which have no charge, “would facilitate the magnetic field containing this tension to cross the solar surface .” In addition, the interaction of neutral particles and charged particles would also help to release this tension, “as if it were a whip”, in the words of the researcher.
The model scientists have used to understand the Sun’s flow motions is called plasma dynamics. Plasma is a very hot, partially ionized gas that flows through magnetic fields. Taking inspiration from the Earth’s own ionosphere, scientists realized that magnetic fields could move more easily between neutral , uncharged particles. In the words of Martínez-Sykora: “normally, magnetic fields are strongly associated with charged particles. If we only considered the latter, those fields would get stuck and could not take off from the surface. On the other hand, when we add the neutral particles, the magnetic fields they move more freely. “
The neutral particles, therefore, would allow the buoyancy that the magnetic knots need to pass through the boiling plasma and reach the surface of the Sun.
References:
Martínez-Sykora, J. (2017). On the generation of solar spicules and Alfvénic waves. Science. DOI: 10.1126 / science.aah541
Image: NASA
