  Experiments on heavy ion collisions performed at GSI (Darmstadt, Germany)
revealed series of narrow quasi-equidistant peaks in the energy distribution of
the produced $e^+e^-$ pairs in the range from 1.5 to 2.0 MeV which are ascribed
to the pair coupling with a strong magnetic field generated by fast nuclei with
$Z\sim90$. The pair is captured in the magnetic trap with dimensions of
$10^{-10}$ cm and average field $\sim 5 \cdot 10^{12}$ Gs and, in turn,
confines this magnetic field in the trap during $\sim 10^{-19}$ s due to the
Alfven effect of magnetic field "freezing-in" into the conducting medium.
