The ESA/NASA Solar Orbiter spacecraft has discovered the presence of numerous elongated tiny jets of material, named dynamic fibrils (DFs), escaping from the active regions of the Sun.
This phenomenon is the basis of new research that could explain the origin of the solar wind. Each jet lasts 20 to 100 seconds and expels the plasma at about 100 km/s.
🆕 The ESA/NASA #SolarOrbiter spacecraft has discovered a multitude of tiny jets of material escaping from the Sun’s outer atmosphere – these jets could be the long-sought-after source of the solar wind 👇https://t.co/G4MFrh8d0q pic.twitter.com/SztsvyOr5h
— ESA (@esa) August 24, 2023
The evidence and data come from an instrument onboard the Solar Orbiter named Extreme Ultraviolet Imager (EUI), which is able to observe solar plasma, of millions of degrees, at a wavelength of 14.4 nanometers.
“We could only detect these tiny jets because of the unprecedented high resolution, high-cadence images produced by EUI” explains Lakshmi Pradeep Chitta, the main author of the paper reporting these findings, named Signatures of Dynamic Fibrils at the coronal base: Observations from Solar Orbiter/EUI.
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Solar chromosphere activity and dynamic fibrils
The solar chromosphere hosts a huge variety of phenomena including Dynamic Fibrils (DF) which are thin elongated jets visible in the solar chromosphere around magnetized regions.
Until now it has never been possible to spot and identify dynamic fibrils (DF) in coronal images, as a consequence of their small size.
By reason of the new discoveries on DFs, the old assumptions made on the solar wind are dropping. Currently developed assumptions state that it is not produced as a steady continuous flow. Indeed the ubiquity of DFs leads us to believe that the solar wind originates from coronal holes as a highly intermittent flow.
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Solar Orbiter
Solar Orbiter is the first mission of the scientific program of the European Space Agency (ESA), called Cosmic Vision 2015-2025. Its purpose is the study of the Sun at close range. The research conducted as a result of this mission is of fundamental importance because, being the Earth immersed in an atmosphere pervaded by plasma and particles emitted by solar activity, it is continuously exposed to such phenomena.
Another main objective of the mission is to explore the almost unknown regions of the Sun such as the solar poles.
Among the observation instruments aboard Solar Orbiter we can find:
- Extreme Ultraviolet Imager (EUI) which is one of the remote sensing instruments. It consists of three telescopes, the Full Sun Imager, and two High-Resolution Imager;
- The Italian Metis coronagraph, which has been financed and managed by the Italian Space Agency, is able to observe the solar corona simultaneously in the visible and ultraviolet bands, thus providing a detailed picture of the processes that govern the expansion of the solar plasma in the interplanetary space.
“It is exciting to see how the images of the solar corona taken by Metis in its field of view integrate very well with those of EUI”, explains Silvano Fineschi, Scientific Director of the Italian contribution to the mission. “This makes it possible to identify the origin of the solar wind and solar storms and to follow their evolution in the heliosphere”.
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