Latest Trends In Observing And Understanding The Dynamics Of The Solar Atmosphere: From MHD Waves To Small-Scale Transients
Observational evidence of kink waves in super penumbral fibrils
Date Submitted
2017-04-12 10:59:16
Krishna Mooroogen
Richard Morton, Vasco Henriques
Northumbria University
Sunspots are well known to support slow magneto-acoustic waves, generated by p-mode absorption and propagate from the photosphere to corona. The slow waves appear as umbral flashes and running penumbral waves in the chromosphere. Inclined magnetic fields a key role in enabling these waves to propagate into the upper solar atmosphere, through the so called ramp effect. It has been suggested that the p-modes can be subject to mode conversion along inclined field lines, generating both fast and Alfvénic MHD wave modes. However, evidence for these waves modes is scant. In this study we present observational evidence of transverse oscillations in chromospheric (Ca II 8542) super penumbral fibrils. We interpret the oscillations as kink waves and suggest they may be the signature of the mode conversion process. We also exploit Fourier analysis to demonstrate that the ramp effect is in action in the studied sunspot, finding a relationship between frequency and distance from the sunspot centre.
Schedule
id
Thursday
date time
09:00 - 10:30
10:00
Abstract
Observational evidence of kink waves in super penumbral fibrils