SPRG Seminars
January 27, 2014: This seminar will take place at the Space Sciences Laboratory, at the Addition Conference Room, at 11AM.
"Fine strand-like structure in the corona from MHD transverse oscillations"
Patrick Antolin, Hinode Science Center, National Astronomical Observatory of Japan (NAOJ)
High resolution observations of the corona with new instruments indicate that the coronal magnetic field may tend to organize itself in fine strand-like structures of a few hundred kilometers widths. Numerical models, however, have so far failed to explain such organization. In this work we present through 3D MHD simulations, a model that easily leads to the generation of strand-like structure in loops. This model is based on the observational finding that the corona is permeated with small amplitude transverse MHD waves. Here we show that even very small amplitudes of these waves lead to Kelvin-Helmholtz instabilities, producing fine scale structure in loops. Through forward modelling we show that the roll-ups (eddies) generated from the instability are velocity sheared regions with enhanced emissivity hosting current sheets, which appear as strand-like structure from the line-of-sight effects. This model further predicts a characteristic increase in line broadening along the loop easily detectable with current spectrometers. An observational setup based on coronal rain observations with IRIS allowing to test this theory will also be discussed in this talk.