  It is interesting to ask how a confinement scale affects the thermalization
of strongly coupled gauge theories with gravity duals. We study this question
for the AdS soliton model, which underlies top-down holographic models for
Yang-Mills theory and QCD. Injecting energy via a homogeneous massless scalar
source that is briefly turned on, our fully backreacted numerical analysis
finds two regimes. Either a black brane forms, possibly after one or more
bounces, after which the pressure components relax according to the lowest
quasinormal mode. Or the scalar shell keeps scattering, in which case the
pressure components oscillate and undergo modulation on time scales independent
of the (small) shell amplitude. We show analytically that the scattering shell
cannot relax to a homogeneous equilibrium state, and explain the modulation as
due to a near-resonance between a normal mode frequency of the metric and the
frequency with which the scalar shell oscillates.
