What is the difference between premixed and diffusion flame?

Two main different combustion regime: diffusion flame is generated when fuel and oxidizer are provided separately and then mixes with each other and reacts in the mixing zone; while premixed flame is generated when fuel and oxidizer are totally mixed and goes to burning after ignition. The main difference is that premixed flame forms a propagating wave front and diffusion flame tends to be stable. Due to that, premixed flame is more sensitive to acoustics, i.e. flashback and blow-off. On the other hand, the mixing is a key factor for diffusion flame. If mixing is not enough, we suffers with high soot and unburnt hydrocarbon emissions. The flame thickness is different a lot, and premixed flame is much thinner. In terms of environment issue, NOx emission is relatively higher in premixed flame than in diffusion flame due to higher flame temperature. In application, safety is a main concern for premixed flame, so that stabilization is always applied in practice. Diffusion flame is more widely applied, especially on aircraft and power station.