  A massively parallel simulation code, called \textit{dHybrid}, has been
developed to perform global scale studies of space plasma interactions. This
code is based on an explicit hybrid model; the numerical stability and parallel
scalability of the code are studied. A stabilization method for the explicit
algorithm, for regions of near zero density, is proposed. Three-dimensional
hybrid simulations of the interaction of the solar wind with unmagnetized
artificial objects are presented, with a focus on the expansion of a plasma
cloud into the solar wind, which creates a diamagnetic cavity and drives the
Interplanetary Magnetic Field out of the expansion region. The dynamics of this
system can provide insights into other similar scenarios, such as the
interaction of the solar wind with unmagnetized planets.
