  A reactive fluid dissolving the surface of a uniform fracture will trigger an
instability in the dissolution front, leading to spontaneous formation of
pronounced well-spaced channels in the surrounding rock matrix. Although the
underlying mechanism is similar to the wormhole instability in porous rocks
there are significant differences in the physics, due to the absence of a
steadily propagating reaction front. In previous work we have described the
geophysical implications of this instability in regard to the formation of long
conduits in soluble rocks. Here we describe a more general linear stability
analysis, including axial diffusion, transport limited dissolution, non-linear
kinetics, and a finite length system.
