  It has been shown that changes in the energy of a system of nonwetting-liquid
clusters confined in a random nanoporous medium in the process of relaxation
can be written in the quasiparticle approximation in the form of the sum of the
energies of local (metastable) configurations of liquid clusters interacting
with clusters in the connected nearest pores. The energy spectrum and density
of states of the local configuration have been calculated. It has been shown
that the relaxation of the state of the system occurs through the scenario of
self-organized criticality (SOC). The process is characterized by the
expectation of a fluctuation necessary for overcoming a local energy barrier of
the metastable state with the subsequent rapid hydrodynamic extrusion of the
liquid under the action of the surface buoyancy forces of the nonwetting
framework. In this case, the dependence of the interaction between local
configurations on the number of filled pores belonging to the infinite
percolation cluster of filled pores serves as an internal feedback initiating
the SOC process. The calculations give a power-law time dependence of the
relative volume of the confined liquid. The developed model of the relaxation
of the porous medium with the nonwetting liquid demonstrates possible
mechanisms and scenarios of SOC for disordered atomic systems.
