I.M. Dremin Lebedev Physical Institute, Russian Academy of Sciences, Leninsky prosp. 53, Moscow, 119991, Russian Federation
The large-distance ultraperipheral collisions of two relativistic ions
are considered. The clouds of photons surrounding the ions are responsible
for their distant electromagnetic interaction. The perturbative approach and
the method of equivalent photons are described. It is shown that the total
cross section of these collisions increases fast with the energy increase and
is especially large for heavy ions. Some experimental data and their comparison
with theoretical approaches are described. Further proposals are discussed.