Hybrid simulation of ion-acoustic waves excitation by non-linear Alfvén wave

The results of one dimensional hybrid simulation of standing Alfvén wave in low beta plasma are presented. Plasma is accelerated from the anti-nodes toward the nodes of the standing waves with finite amplitude under the action of the variable magnetic field pressure. As a result, a sharp maximum of the number density (and electron pressure) arises near the nodes of the standing wave. The plasma flow is spatially modulated with half wavelength of the driving Alfvén wave. Standing ion-acoustic waves produced by spatial modulation of the flow are observed in hybrid simulation. The effective parallel electric field E∗=E+1ne∇pe appears due to both electron pressure gradient near the nodes and electron pressure variations in the acoustic waves.