Atomic physics of high Z-systems

The atomic physics of high-Z systems is discussed in this review. The Unilac of the G.S.I. Darnstadt accelerated for the first time 238U ions to an energy of 1.6GeV, which is high enough to overcome the Coulomb barrier in U-U collisions. This event opened a new field of atomic physics: the investigation of atomic processes in strong fields with coupling strengths. These fields are produced in heavy ion-atom collisions by superposition of the Coulomb fields of both colliding nuclei. Experimental techniques were utilized which helped to gain information on the formation and properties of quasitons. They included inner shell ionization in adiabatic heavy ion-atom collisions, high energy rays from high Z-quasiatoms, and pair creation in heavy ion-atom collisions