Dissolution in a field - art. no. 041606

We study the dissolution of a solid by continuous injection of reactive "ac id" particles at a single point, with the reactive particles undergoing bia sed diffusion in the dissolved region. When acid encounters the substrate m aterial, both an acid particle and a unit of the material disappear. We fin d that the lengths of the dissolved cavity parallel and perpendicular to th e bias grow as t(2/(d+1)) and t(1/(d+1)), respectively, in d dimensions, wh ile the number of reactive particles within the cavity grows as t(2/(d+1)). We also obtain the exact density profile of the reactive particles and the relation between this profile and the motion of the dissolution boundary. The extension to variable acid strength is also discussed.