  Topologically non-trivial configurations of the hypermagnetic flux lines lead
to the formation of hypermagnetic knots (HK) whose decay might seed the Baryon
Asymmetry of the Universe (BAU).HK can be dynamically generated provided a
topologically trivial (i.e. stochastic) distribution of flux lines is already
present in the symmetric phase of the electroweak (EW) theory. In spite of the
mechanism generating the HK, their typical size must exceed the diffusivity
length scale. In the minimal standard model (MSM) (but not necessarily in its
supersymmetric extension) HK are washed out. A classical hypermagnetic
background in the symmetric phase of the EW theory can produce interesting
amounts of gravitational radiation.
