This paper provides a brief review of basic solar wind theory and makes use of the Laval nozzle analogy to elucidate the characteristic features of a solar wind driven by thermal and Alfven wave pressure. It is argued that there is a considerable body of evidence in favour of wave acceleration of high speed solar wind. Moreover we advocate that short period waves (<1 second) are responsible for heating and accelerating the wind in coronal holes. These waves may be generated by small scale reconnection events (microflares) in regions where the magnetic field is not strictly unipolar.