  We study the spontaneous scalarization of a standard conducting charged
sphere embedded in Maxwell-scalar models in flat spacetime, wherein the scalar
field $\phi$ is nonminimally coupled to the Maxwell electrodynamics. This setup
serves as a toy model for the spontaneous scalarization of charged (vacuum)
black holes in Einstein-Maxwell-scalar (generalized scalar-tensor) models. In
the Maxwell-scalar case, unlike the black hole cases, closed-form solutions
exist for the scalarized configurations. We compute these configurations for
three illustrations of nonminimal couplings: one that \textit{exactly}
linearizes the scalar field equation, and the remaining two that produce
nonlinear continuations of the first one. We show that the former model leads
to a runaway behaviour in regions of the parameter space and neither the
Coulomb nor the scalarized solutions are stable in the model; but the latter
models can heal this behaviour producing stable scalarized solutions that are
dynamically preferred over the Coulomb one. This parallels reports on black
hole scalarization in the extended-scalar-Gauss-Bonnet models. Moreover, we
analyse the impact of the choice of the boundary conditions on the
scalarization phenomenon. Dirichlet and Neumann boundary conditions accommodate
both (linearly) stable and unstable parameter space regions, for the
scalar-free conducting sphere; but radiative boundary conditions always yield
an unstable scalar-free solution and preference for scalarization. Finally, we
perform numerical evolution of the full Maxwell-scalar system, following
dynamically the scalarization process. They confirm the linear stability
analysis and reveal that the scalarization phenomenon can occur in
qualitatively distinct ways.
