The outflow of coronal plasma into interplanetary space is a consequence of the coronal heating process. Therefore the formation of the corona and the acceleration of the solar wind should be treated as a single problem. The deposition of energy into the corona through some mechanical or electromagnetic energy flux is balanced by the various sinks available to the corona, and the sum of these processes determines the coronal structure, i.e. its temperature and density. Heating of the extended solar corona leads to high proton and ion temperatures and relatively low electron temperatures. This is due to the low heat conductivity in the proton (ion) gas as compared to the electrons. To a fairly good approximation we can say that most of the energy flux deposited in the protons and ions is lost as kinetic and gravitational energy flux in the solar wind flow, whereas a large fraction of the energy flux added to the electrons is conducted back into the transition region and lost as radiation. In order to drive high speed wind most of the energy must be deposited in the ions. ©1999 American Institute of Physics.