  Enhancement of nuclear pasta formation due to multi-nucleus simultaneous
collision is presented based on time-dependent density functional calculations
with periodic boundary condition. This calculation corresponds to the situation
with density lower than the known low-density existence limit of the nuclear
pasta phase. In order to evaluate the contribution from three-nucleus
simultaneous collisions inside the cosmic matter, the possibility of
multi-nucleus simultaneous collisions is examined by a systematic Monte-Carlo
calculation, and the mean free path of a nucleus is obtained. Consequently the
low-density existence limit of the nuclear pasta phase is formed to be lower
than believed up to now.
