José Roberto Canivete Cuissa successfully defended his thesis work «Numerical Simulations of Magneto-Convection: From Stellar Dynamos to Small-Scale Swirling Motions» on August 31, 2023 at the Institute for Computational Science of the University of Zürich. «Roberto» as he is commonly called, is from Riviera (TI) and carried out his doctoral thesis at IRSOL in the numerical simulations group of Oskar Steiner. His main topic of research was small swirling motions in the solar atmospheres that resemble terrestrial tornadoes but different from those are connected to magnetic fields. These magnetic tornadoes have been discovered by observations of the Sun only two decades ago.
Roberto analyzed numerical simulations of the solar atmosphere and discovered that these tornadoes are pulses of torsional Alfvén waves that propagate along magnetic lines of force in the vertical direction from the solar surface to the outer solar atmosphere. Thus, they can transport mechanical energy from the solar surface to the chromosphere and the corona, where they may dissipate and turn this energy into heat. On the way to this discovery, Roberto derived a novel hydrodynamic equation for the swirling strength, a quantity similar to the vorticity but better suited as a measure for the strength of vortical motion. He also created an innovative software tool for finding vortical motions in a two-dimensional flow-field (available under https://github.com/jcanivete/swirl) and he applied it to numerical simulations of the solar and stellar atmospheres for a statistical analysis. The SWIRL code can also be used in different fields of research, such as in local climate research as it was recently done. Beyond that, Roberto carried out magnetohydrodynamic simulations of stellar magneto-convection for which he modified the well-known simulation code RAMSES, making it fit for stellar and solar applications.
His results got published in five peer-reviewed articles in «Astronomy & Astrophysics», one of the highest regarded astrophysical journal. Furthermore, Roberto also substantially contributed to a review article on vortex motions in the solar atmosphere and to a scientific article that resulted from a student project at University of Zürich on intensity interferometry, both in peer-reviewed astrophysical journals.
At IRSOL, we congratulate Dr. José Roberto Canivete Cuissa for his splendid achievements!