The visible universe is 99.999% plasma. So quite simply, if you don't know how cosmic plasmas behave, you don't know the Universe. And astrophysical plasmas may behave differently to terrestrial plasmas.
It is worth noting that all cosmic plasma carries a magnetic field and electric currents. Even plasmas that are less than 1% ionized, may behave as a plasma, as do dusty plasmas (ie. "dust grains can be the dominant current carrier")