The efficiency of non-modal self-heating by acoustic wave perturbations is examined. Considering different kinds of kinematically complex velocity patterns, we show that non-modal instabilities arising in these inhomogeneous flows may lead to significant amplification of acoustic waves. Subsequently, the presence of viscous dissipation damps these amplified waves and causes the energy transfer back to the background flow in the form of heat; viz. closes the 'self-heating' cycle and contributes to the net heating of the flow patterns and the chromospheric network as a whole. The acoustic self-heating depends only on the presence of kinematically complex flows and dissipation. It is argued that together with other mechanisms of non-linear nature the self-heating may be a probable additional mechanism of non-magnetic chromospheric heating in the Sun and other solar-type stars with slow rotation and extended convective regions.
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