  We show that convection in the stellar photosphere generates plasma waves by
an irreversible process akin to Zeldovich superradiance. In the Sun, this
mechanism is most efficient in quiet regions with magnetic fields of order one
gauss. Most of the energy is carried by Alfven waves with megahertz
frequencies, which travel upwards until they reach a height at which they
dissipate via mode conversion. A power flux estimate shows that this mechanism
offers a plausible explanation of how energy is persistently transported from
the colder photosphere to the hotter corona.
