  A microscopic bubble of soluble gas always dissolves in finite time in an
under-saturated fluid. This diffusive process is driven by the difference
between the gas concentration near the bubble, whose value is governed by the
internal pressure through Henry's law, and the concentration in the far field.
The presence of neighbouring bubbles can significantly slow down this process
by increasing the effective background concentration and reducing the diffusing
flux of dissolved gas experienced by each bubble. We develop theoretical
modelling of such diffusive shielding process in the case of small microbubbles
whose internal pressure is dominated by Laplace pressure. We first use an exact
semi-analytical solution to capture the case of two bubbles, analyse in detail
the shielding effect and show that hydrodynamic effects are mostly negligible
except in the case of almost-touching bubbles. In order to tackle the case of
multiple bubbles, we then derive and validate two analytical approximate yet
generic frameworks, first using the method of reflections and then by proposing
a self-consistent continuum description. Using both modelling frameworks, we
examine the dissolution of regular 1D, 2D and 3D bubble lattices. Bubbles
located at the edge of the lattices dissolve first, while innermost bubbles
benefit from the diffusive shielding effect, leading to the inward propagation
of a dissolution front within the lattice. We show that diffusive shielding
leads to severalfold increases in the dissolution time which grows
logarithmically with the number of bubbles in 1D-lattices and algebraically in
two and three dimensions, scaling respectively as its square root and
2/3-power. We further illustrate the sensitivity of the dissolution patterns to
initial fluctuations in bubble size or arrangement in the case of large and
dense lattices, as well as non-intuitive oscillatory effects.
