Plasma Symphony, or MHD Waves In the Solar Corona

Solar corona has been one of the most mysterious regions of the Solar system. Two things cause the main interest to that part of solar atmosphere. The first one is that it is the region, where the most energetic events in the Solar system occur, including solar flares and mass ejections. Second, solar corona is a natural laboratory, where we can study various plasma processes. High-precision instruments, which are used to register solar radio emissions and UV and X-ray radiation, invisible to the naked eye, reveal diverse wave phenomena – stationary or running disturbances in plasma and magnetic field, which permeates the corona. As a rule their wavelength exceeds 1000 kilometers and their periods are greater than 1 second. The waves observed belong to several different types predicted by magneto hydrodynamics (MHD). One can imagine the set of those waves as a peculiar ‘music’, played by solar corona. Having ‘listened’ to it and analyzed it, one can get important and often unique data about physical properties of solar plasma and the processes in it.

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