학술논문
First polar observations of the fast solar wind with the Metis - Solar Orbiter coronagraph: Role of 2D turbulence energy dissipation in the wind acceleration
Document Type
Author
Telloni, D.; Antonucci, E.; Adhikari, L.; Zank, G. P.; Giordano, S.; Vai, M.; Zhao, L. -l.; Andretta, V.; Burtovoi, A.; Capuano, G. E.; Da Deppo, V.; De Leo, Y.; Fineschi, S.; Grimani, C.; Heinzel, P.; Jerse, G.; Landini, F.; Liberatore, A.; Moses, J. D.; Naletto, G.; Nicolini, G.; Pancrazzi, M.; Romoli, M.; Russano, G.; Sasso, C.; Slemer, A.; Spadaro, D.; Stangalini, M.; Susino, R.; Teriaca, L.; Uslenghi, M.; Sorriso-Valvo, Luca; Marino, R.; Perrone, D.; D'Amicis, R.; Bruno, R.
Source
Astronomy and Astrophysics. 670
Subject
Language
English
ISSN
0004-6361
1432-0746
1432-0746
Abstract
Context. The fast solar wind is known to emanate from polar coronal holes.Aims. This Letter reports the first estimate of the expansion rate of polar coronal flows performed by the Metis coronagraph on board Solar Orbiter.Methods. By exploiting simultaneous measurements in polarized white light and ultraviolet intensity of the neutral hydrogen Lyman-α line, it was possible to extend observations of the outflow velocity of the main component of the solar wind from polar coronal holes out to 5.5 R⊙, the limit of diagnostic applicability and observational capabilities.Results. We complement the results obtained with analogous polar observations performed with the UltraViolet Coronagraph Spectrometer on board the SOlar and Heliospheric Observatory during the previous full solar activity cycle, and find them to be satisfactorily reproduced by a magnetohydrodynamic turbulence model.Conclusions. This suggests that the dissipation of 2D turbulence energy is a viable mechanism for coronal plasma heating and the subsequent acceleration of the fast solar wind.