  In this paper, we obtain the Nth-order rational solutions for the defocusing
nonlocal nonlinear Schrodinger equation by the Darboux transformation and some
limit technique. Then, via an improved asymptotic analysis method relying on
the balance between different algebraic terms, we derive the explicit
expressions of all asymptotic solitons of the rational solutions with the order
1<=N<=4. It turns out that the asymptotic solitons are localized in the
straight or algebraic curves, and the exact solutions approach the curved
asymptotic solitons with a slower rate than the straight ones. Moreover, we
find that all the rational solutions exhibit just five different types of
soliton interactions, and the interacting solitons are divided into two halves
with each having the same amplitudes. Particularly for the curved asymptotic
solitons, there may exist a slight difference for their velocities between at t
and -t with certain parametric condition. In addition, we reveal that the
soliton interactions in the rational solutions with N>=2 are stronger than
those in the exponential and exponential-and-rational solutions.
