Higher harmonic flow in heavy ion collisions at different beam energies

The anisotropic flow in heavy ion collisions at ultra-relativistic energies is expected to provide information about the early stages of the evolution of the system. It may also provide information about the reaction dynamics and fluctuations at the initial stage of the collision. The anisotropic flow arises when the spatial anisotropy at the early times after the collision gets converted into momentum anisotropy. The strength of the anisotropic flow is usually written with a Fourier decomposition of the azimuthal distribution of observed particles relative to the reaction plane