Vortex flows and magnetic tornadoes on the Sun and cool stars
The Research Council of Norway has funded the project “Vortex flows and magnetic tornadoes on the Sun and cool stars” for the period 2013 to 2017. The aim of the VORTEX project is the comprehensive study of vortex flows and magnetic tornadoes on the Sun and other stars.
About the project
The project focuses on the small-scale magnetic tornadoes, which have been discovered recently on the Sun. This discovery together with an explanation of the basic physical mechanism has been published in the journal Nature in 2012 (Vol. 486, 505 - 508, http://www.nature.com/nature/journal/v486/n7404/full/nature11202.html). See also http://www.solartornado.info.
Magnetic tornadoes are thought to be abundant on our Sun. They are generated by vortex flows, which form due to the bathtub effect at the solar surface and force the footpoints of magnetic field concentrations to rotate. The magnetic fields extend through the atmospheric layers and thus mediate the rotation upwards, resulting in a net energy transport into the upper layers. There, the energy is dissipated by yet unknown physical processes and may contribute to the heating of the solar corona to temperatures in excess of a million degree Kelvin.
The VORTEX project addresses many fundamental and yet unknown aspects of this novel phenomenon through a combination of high-resolution observations with world-leading facilities like the ground-based Swedish 1-m Solar Telescope (SST) and the space-borne observatories Solar Dynamics Observatory and advanced numerical simulations with state-of-the-art 3-D radiative magnetohydrodynamics computer codes.
Similar 3-D simulations for red dwarf stars (which constitute about 75 % of all stars in our galaxy) will reveal if the tornado phenomenon is of general importance for cool stars.
3D visualization of a close-up region from a numerical simulation of the solar atmosphere. The lower surface represents the granulation and magnetic footpoints at the bottom of the photosphere (i.e., the solar "surface"), whereas the other planes show the horizontal velocity in the atmosphere above. Next to the magnetic field lines (red), the red/orange/red streamlines show the spiral paths of plasma that gave the phenomenon its name - "magnetic tornado".
Further information and links:
- Project wiki pages (restricted access): https://wiki.uio.no/mn/astro/tornado