An astrophysical plasma is a plasma (an ionized gas) the physical properties of which are studied as part of astrophysics. Much of the baryonic matter of the universe is thought to consist of plasma, a state of matter in which atoms and molecules are so hot, that they have ionized by breaking up into their constituent parts, negatively charged electrons and positively charged ions. Because the particles are charged, they are strongly influenced by electromagnetic forces, that is, by magnetic and electric fields.
All known astrophysical plasmas are influenced by magnetic fields. Since plasmas contain equal numbers of electrons and ions, they are electrically neutral overall and thus electric fields play a lesser dynamical role. Because plasmas are highly conductive, any charge imbalances are readily neutralised.