The energy requirements of microturbulence.

Summary. The flux of energy required to maintain microturbulence against viscous dissipation has been calculated assuming that it results from a progressive longitudinal wave. This has been applied to the Sun, a metallic line star 63 Tauri with a large microturbulent velocity and a B type star. In these stars the flux of energy required is at least 100 times greater than the calculated acoustic flux generated by the convection zone. For 63 Tauri the flux required is 10 % of the total radiative flux, so that the energy requirements are severe but not impossible. In B type stars the flux required is only 10 of the radiative flux, but such stars do not have significant convection zones and there is no mechanism to explain microturbulence. Key words: microturbulence - viscous dissipation - convection - acoustic flux