Subject: Why do carbon particles shoot out from a lighted wick?

In the pool of liquid wax below a lighted candle wick carbon fragments 
shoot out vety fast on the surface.  They sink and travel back slowly, thay 
circulate slowly upward near the wick and shoot out quickly again.  
Intuition suggests that the particles should rise fastest near the heat 
source where convection should be maximal.  Not so in practice.

Re: Why do carbon particles shoot out from a lighted wick?