8-12 July 2013
Acoustic resonators above sunspot umbrae
Presented by Dr. G.J.J. BOTHA on 10 Jul 2013 from 14:50 to 15:10
Type: Oral Presentation
Session: Space Science
Track: Track D2 - Space Science
The three-minute oscillations in the chromosphere above sunspot umbrae are explained by means of an acoustic resonator. In the vertical magnetic field above umbrae a cavity forms between the photosphere and transition region that acts as a leaky resonator, where the oscillations generate traveling waves that propagate upward into the solar corona. One-dimensional numerical simulations using the ideal magnetohydrodynamic equations demonstrate the existence of the resonator. The shapes and peaks in the resonating spectrum raise the possibility of using the resonator as a means to determine the chromospheric temperature profile above umbrae. A numerical study will be presented of different initiators of the oscillations, as well as the influence of the shape and height of the chromospheric cavity.