Heating and deceleration of minor ions in the extended fast solar wind by oblique Alfven waves

Using one-dimensional hybrid simulations, the interaction between oblique propagating Alfven waves and minor ions in the fast solar wind stream is investigated in this paper. In typical fast solar wind conditions, these waves and the drifting minor ions satisfy the ion cyclotron resonance condition: omega = -Omega(i) + k(vertical bar vertical bar) v(vertical bar vertical bar). (Here omega is the wave angular frequency, Omega(i) is the gyration frequency of an ion species i, k(vertical bar vertical bar) is the wave number component along the background magnetic field B-0, and v k is the particle velocity component of the ion species parallel to B-0.) These waves are able to heat minor ions while decelerating them at the same time. The heating is primarily in the direction perpendicular to the background magnetic field, and the deceleration helps to restrict minor ion and proton beam-drifting speed at or just lower than the local Alfven speed (in relative to the speed of the core proton component).