Resonant MHD wave instabilities in the solar atmosphere

Resonant MHD waves occur naturally in inhomogeneous plasmas like the solar atmosphere. When there is a plasma bulk motion present the wave-steady plasma interaction may result in increasing wave amplitude and the wave carrying energy away instead of the usual damping (and heating of the inhomogeneous plasma). This phenomenon is called resonant flow instability (RFI). Such situation may occur in blinkers, in sunspot penumbrae, at the boundary of coronal loops and coronal holes, in the shear layers of slow and fast solar wind or at the magneto- and heliopause. We report on the negative energy character and on the unstable nature of waves in shear flows throughout solar atmospheric conditions.