Dynamics of a probe null string in the gravitational field of a closed null string radially collapsing in the plane

Abstract

We consider the dynamics of a probe null string in the gravitational field of a closed (“thick”) null string radially collapsing in a plane. Analysis of the obtained solutions suggests that there might exist several properties of a null-string gas interesting from the cosmological standpoint, such as acceleration of expansion or contraction, a granular structure of the gas, the emergence of stable polarized states, and a domain structure.