Electromagnetic heavy-ion/proton instabilities

Ion/ion instabilities are driven by the relative velocity v(o) of two disti nct ion components. This manuscript reports linear theory and simulation st udies of electromagnetic ion/ion instabilities for a warm proton component streaming against a cool, heavy ion component in a homogeneous, magnetized, collisionless plasma in which v(o) is parallel or antiparallel to the back ground magnetic field. Under these conditions linear Vlasov dispersion theo ry predicts that the fastest growing mode is usually the right-hand polariz ed proton resonant instability. Two-dimensional initial value hybrid simula tions of this growing mode are carried out, yielding scaling relations for the maximum fluctuating magnetic field energy density and the proton pickup time. The latter is proportional to the inverse of the maximum growth rate for a wide range of plasma parameters.