title: High-frequency torsional Alfvén waves as an energy source for coronal heating.
abstract: The existence of the Sun's hot atmosphere and the solar wind acceleration continues to be an outstanding problem in solar-astrophysics. Although magnetohydrodynamic (MHD) modes and dissipation of magnetic energy contribute to heating and the mass cycle of the solar atmosphere, yet direct evidence of such processes often generates debate. Ground-based 1-m Swedish Solar Telescope (SST)/CRISP, Hα 6562.8 Å observations reveal, for the first time, the ubiquitous presence of high frequency (~12-42 mHz) torsional motions in thin spicular-type structures in the chromosphere. We detect numerous oscillating flux tubes on 10 June 2014 between 07:17 UT to 08:08 UT in a quiet-Sun field-of-view of 60" × 60" (1" = 725 km). Stringent numerical model shows that these observations resemble torsional Alfvén waves associated with high frequency drivers which contain a huge amount of energy (~105W m-2) in the chromosphere. Even after partial reflection from the transition region, a significant amount of energy (~103W m-2) is transferred onto the overlying corona. We find that oscillating tubes serve as substantial sources of Alfvén wave generation that provide sufficient Poynting flux not only to heat the corona but also to originate the supersonic solar wind.
authors.affiliation: Department of Physics, Indian Institute of Technology (BHU), Varanasi-221005, India.
authors.forename: Abhishek Kumar
authors.initials: AK
authors.lastname: Srivastava
authors.affiliation: Armagh Observatory, College Hill, Armagh, BT61 9DG, N. Ireland.
authors.forename: Juie
authors.initials: J
authors.lastname: Shetye
authors.affiliation: Group of Astrophysics, Institute of Physics, UMCS, Lublin, Poland.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Murawski
authors.affiliation: Armagh Observatory, College Hill, Armagh, BT61 9DG, N. Ireland.
authors.forename: John Gerard
authors.initials: JG
authors.lastname: Doyle
authors.affiliation: INAF-OAR National Institute for Astrophysics, 00040, Monte Porzio Catone, RM, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Stangalini
authors.affiliation: Department of Mathematics &Information Sciences, Northumbria University, Newcastle Upon Tyne, NE1 8ST, UK.
authors.forename: Eamon
authors.initials: E
authors.lastname: Scullion
authors.affiliation: Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2, Ireland.
authors.forename: Tom
authors.initials: T
authors.lastname: Ray
authors.affiliation: Group of Astrophysics, Institute of Physics, UMCS, Lublin, Poland.
authors.forename: Dariusz Patryk
authors.initials: DP
authors.lastname: Wójcik
authors.affiliation: Department of Physics, Indian Institute of Technology (BHU), Varanasi-221005, India.
authors.forename: Bhola N
authors.initials: BN
authors.lastname: Dwivedi