  We predict the new type of phase transition in quasi one-dimensional system
of interacting electrons at high magnetic fields, the stabilization of a
density wave which transforms a two dimensional open Fermi surface into a
periodic chain of large pockets with small distances between them. We show that
quantum tunneling of electrons between the neighboring closed orbits enveloping
these pockets transforms the electron spectrum into a set of extremely narrow
energy bands and gaps that decreases the total electron energy, thus leading to
a \emph{magnetic breakdown induced density wave} ground state analogous to the
well-known instability of Peierls type.
