  We propose a mechanism for the early generation of the mean Intracluster
magnetic field in terms of magnetized galactic winds. These winds are the
result of starburst phases of the cluster galaxies, assumed to produce the
predominant population of early type galaxies in mergers of gas-rich
progenitors. After further cluster contraction typical field strengths are
$10^{-7}$ Gauss. This estimate may increase to the level of $10^{-6}$ Gauss if
more extreme galactic parameters, and subsequent shear amplification of the
field are considered. The topology of the field is one of almost unconnected
Wind Bubbles with Parker-type spiral field configurations over scales of the
distance between galaxies. Further cluster accretion, that continues
chaotically in space and time up to the present, will perturb these
"large-scale" mean fields on smaller or at best comparable spatial scales. The
small scale fields in the resulting turbulent fluctuation spectrum should be
able to confine relativistic particles over times longer than the age of the
Universe. The nonthermal particle content of galaxy clusters should therefore
also have a "cosmological" hadronic component generated during the early
starburst phase of the member galaxies. Already by itself it implies a
nonthermal energy fraction of about 10 percent for the Intracluster gas which
should then be detectable by future gamma-ray telescopes.
