Unveiling the magnetic nature of chromospheric vortices

Abstract

Vortex structures in the Sun's chromosphere are believed to channel energy between different layers of the solar atmosphere. We investigate the nature and dynamics of two small-scale quiet-Sun rotating structures in the chromosphere. We analyse two chromospheric structures that show clear rotational patterns in spectropolarimetric observations taken with the Interferometric Bidimensional Spectrometer (IBIS) at the Ca II 8542 Å~ line. We present the detection of spectropolarimetric signals that manifest the magnetic nature of rotating structures in the chromosphere. Our observations show two long-lived structures of plasma that each rotate clockwise inside a 10 arcsec${}^2$~ quiet-Sun region. Their circular polarization signals are 5-10 times above the noise level. Line-of-sight Doppler velocity and horizontal velocity maps from the observations reveal clear plasma flows at and around the two structures. An MHD simulation shows these two structures are plausibly magnetically connected. Wave analysis suggests that the observed rotational vortex pattern could be due to a combination of slow actual rotation and a faster azimuthal phase speed pattern of a magneto-acoustic mode. Our results imply that the vortex structures observed in the Sun's chromosphere are magnetic in nature and that they can be connected locally through the chromosphere.

arXiv comment6 pages, 9 figures, accepted for A&A. Some figures are a low-quality version of the original ones

References in corpus (15)

• The Imaging Magnetograph eXperiment (IMaX) for the Sunrise balloon-borne solar observatory
• SUNRISE/IMaX observations of convectively driven vortex flows in the Sun
• Small-scale swirl events in the quiet Sun chromosphere
• Formation and Eruption of an Active Region Sigmoid: I. Study by Nonlinear Force-Free Field Modeling
• Alfvén waves in simulations of solar photospheric vortices
• Evidence of photospheric vortex flows at supergranular junctions observed by FG/SOT (Hinode)
• Spectropolarimetric capabilities of Ca II 8542 A line
• Are giant tornadoes the legs of solar prominences?
• Vortices in simulations of solar surface convection
• Ubiquitous Solar Eruptions Driven by Magnetized Vortex Tubes
• On the plasma flow inside magnetic tornadoes on the Sun
• Simulations Show that Vortex Flows could Heat the Chromosphere in Solar Plage
• Persistent magnetic vortex flow at a supergranular vertex
• Automated Swirl Detection Algorithm (ASDA) and Its Application to Simulation and Observational Data
• Co-spatial velocity and magnetic swirls in the simulated solar photosphere

Cited by in corpus (9)

• The European Solar Telescope
• Waves in the lower solar atmosphere: the dawn of next-generation solar telescopes
• Stirring the Base of the Solar Wind: On Heat Transfer and Vortex Formation
• Magnetic Tornado Properties: A Substantial Contribution to the Solar Coronal Heating via Efficient Energy Transfer
• IBIS-A: The IBIS data Archive. High resolution observations of the solar photosphere and chromosphere with contextual data
• Photospheric downflows observed with SDO/HMI, HINODE, and an MHD simulation
• On the 5-Minute Oscillations of Photospheric and Chromospheric Swirls
• Analysis of Pseudo-Lyapunov Exponents of Solar Convection Using State-of-the-Art Observations
• Automated analysis of oscillations in coronal bright points