Relativistic hydrodynamics of quark-gluon plasma and stability of scaling solutions

This is the authors' abstract. We don't add key points for this paper.

The scaling solutions of the relativistic hydrodynamics are expected to play an important role in describing the expansion stage of a quark-gluon plasma which may be formed in nucleus-nucleus collisions at high energies. After summarizing some general properties of the scaling solutions, we study in detail their stability against small perturbations. In some typical cases of the two-dimensional scaling solution it is found that (i) the scaling solution is stable if the Reynolds number R defined in terms of the viscosity coefficients is larger than a critical value Rc (=1), (ii) it is also stable for a long-wavelength perturbation if R is small enough, and (iii) it becomes unstable when R approaches Rc from below. It is also shown that these results are related to the time dependence of the Reynolds number, the entropy density, and the temperature, and the point R=Rc corresponds to a critical instant when the heating due to the dissipative processes balances with the cooling due to the expansion of the fluid. The stability of the scaling solution of the quark-gluon plasma is examined for typical ranges of the relevant parameters.