How to set uniform atmospheric pressure (and uniform pressure from within)?

So say we have a unit sized hollow sphere. It has an inner radius r and outer radius R and when meshed looks like this:

(image source:

I want to see how such mesh being created from some material
M would react to uniform atmospheric pressure from outside P and uniform inner pressure p from within. The main idea for me is to deform shell in future yet keep uniform pressure on its surfaces.

How one can set conditions for uniform inner/outer pressure in FEniCS?