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School of Physics and Astronomy

Astronomy Unit Seminar - On MHD waves in localised magnetic solar structures - Where are we with solar atmospheric heating and diagnostics in the dawn of DKIST, EST...

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30 November 2018

Time: 2:30 - 4:30pm

Satellite and ground-based observations from e.g. SOHO, TRACE, STEREO, Hinode, SDO and IRIS to DST/ROSA, IBIS, CoMP, STT/CRISP have provided a wealth of evidence of waves and oscillations present in a wide range of spatial and temporal scales of the magnetised solar atmosphere. Our understanding about localised solar structures has been considerably changed in light of these superb spatial and temporal resolution observations. However, MHD waves not only enable us to perform sub-resolution solar magneto-seismology but are also potential candidates to carry and damp the observed non-thermal energy in localised MHD waveguides. 
First, we will briefly outline the basic recent developments in MHD wave theory focussing on linear waves both in symmetric and asymmetric waveguides. This latter may be an important aspect for the soon commencing fantastic kitty: DKIST.
Next, we will concentrate on the role of the most frequently studied wave classes, including the mysterious Alfven, and magneto-acoustic kink and sausage waves. The current theoretical (and often difficult) interpretations of the detected solar atmospheric wave and oscillatory phenomena within the framework of MHD will be addressed. Their photospheric origin, generation mechanism(s) and how these waves penetrate into the chromosphere, transition region or even into the corona will be discussed. 
Last, the latest reported observational findings of potential MHD wave flux, in terms of localised plasma heating, in the solar atmosphere with some surprising results will be reviewed, bringing us closer to solve the coronal heating problem.