Disappearance of flow

We investigate the disappearance of collective flow in the reaction plane in heavy-ion collisions within a microscopic model (QMD). A systematic study of the impact parameter dependence is performed for the system Ca+Ca. The balance energy strongly increases with impact parameter. Momentum dependent interactions reduce the balance energies for intermediate impact parameters b{}4.5 fm. For the heavy system Au+Au, dynamical negative flow is not visible in the laboratory frame but does exist if the initial precontact rotation of the system due to the Coulomb potential is subtracted. For semiperipheral collisions of Ca+Ca with b{}6.5 fm a new two-component flow is discussed. Azimuthal distributions exhibit strong collective flow signals, even at the balance energy.