7th Asia-Pacific Conference on Plasma Physics, 12-17 Nov, 2023 at Port Messe Nagoya

Small-scale vortices in solar plasmas and their dynamics
K. Tziotziou1
1IAASARS, National Observatory of Athens
e-mail (speaker): kostas@noa.gr

Small-scale vortical motions at granular scales withdynamic timescales of a few minutes, that result from theturbulent dynamics of subsurface solar convection,
appear within intergranular lanes, and largely populate
the solar surface and the atmosphere above. They often
lead, when interacting with co-local magnetic field
concentrations, to the formation of magnetic tornadoes
that penetrate several layers of the solar atmosphere fromthe photosphere up to the low corona. [1]Figure 1 schematically illustrates different types ofvortical flows in the solar atmosphere that are driven bydifferent mechanisms such as rotation resulting from theconservation of angular momentum, photophericrotational flows, rotating magnetic structures or plasma
motion along twisted magnetic structures. Vortices often
exhibit substructure[2] related to their complex dynamics
or waves.
The rich tapestry of such flows is presently explored byhigh-resolution, ground-based observations and state-ofthe-art magnetoconvection simulations and (magneto)hydrostatic models. Detection methods of solar vortices
in the solar photosphere are based on tracking of flow
velocities (and relevant tensors and metrics), that either
exist (in numerical datasets) or are reconstructed withLocal Correlation Tracking (LCT) techniques (inobservations). In more complex layers such as the solar

chromosphere, where proper derivation of flow
velocities with LCT is problematic, observational
detection of chromospheric swirls is based onmorphological[3] methods.
Small-scale vortex flows likely affect the dynamics ofthe quiet Sun and coronal holes solar chromosphere, andtransfer mass and energy between the photosphere andthe corona. The twisting and dynamics of the magnetic
field lines within them are ideal for driving a wide
variety of oscillations and for initiating a multitude of
MHD waves[4,5], mainly of Alfvenic type, and flows thatcan potentially contribute to the solar atmosphericenergetics at different heights.
With the combined use of observations and simulations
we explore and discuss the nature and detection of vortex
flows in the solar atmosphere, their physical properties
and relevant dynamics and their role in the excitation andpropagation of waves and the energetics of the solaratmosphere.
References[1] K. Tziotziou et al, Space Sci Rev 219, 1 (2023)[2] K. Tziotziou et al, Astron Astrophys 618, 51 (2018)[3] I. Dakanalis et al, Sol Phys 296, 17 (2021)[4] V. Fedun et al, Ann Geophys 29, 1029 (2011)[5] K. Tziotziou et al, Astron Astrophys 643, 166 (2020)

Figure 1. Schematic illustration of different types of small-scale vortex flows and related phenomena in the solar
atmosphere (see figure legend for description). Shades of brown indicate solar granulation with arrows in foremost
granules representing the convective flow field. Blue and red lines show, respectively, the magnetic field lines andinstantaneous streamlines, while green arrows indicate the rotation of magnetic flux structures. From Tziotziou et al(2023)[1].