Magnetic field generation from bubble collisions during first-order
  phase transition
  We study the magnetic fields generation from the cosmological first-order
electroweak phase transition. We calculate the magnetic field induced by the
variation of the Higgs phase for two bubbles and three bubbles collisions. Our
study shows that electromagnetic currents in the collision direction produce
the ring-like magnetic field in the intersect regions of colliding bubbles,
which may seed the primordial magnetic field that are constrained by
intergalatic field observations.
