Kinetic evolution and acceleration of the solar wind

Abstract

Abstract. We investigate the effects of kinetic waveparticle interactions on the solar wind using a global hybrid model. The model follows the evolution of the particle distributions along an inhomogeneous field line under the influence of wave-particle interactions, an ambipolar electric field that is consistent with the particle distributions themselves, and Coulomb collisions. This represents the "first results" of global evolutionary study of the solar wind that take into account these kinetic effects. The model can account for the bulk acceleration of the solar wind, the preferential heating of the helium ions over the protons, as well as the occasionally observed double-peaked proton velocity distributions. the global evolution of the ion distributions is based on kinetic calculations that, among other major effects, also take into account the Coulomb interactions, including those among the same ion species. The suprathermal electrons, which are the tail portion of the thermal electron distribution at the lower boundary, are also described by a similar approach, except that they are treated as test particles due to their low relative density. The bulk thermal electrons, assumed to be in a drifting Maxwellian, and the arebipolar field are determined with a fluid approach. When combined with Monte Carlo modeling of ion resonant heating, the technique enables us not only to follow the global evolution of the solar wind particle distributions under the effect of wave-particle interactions, but also to determine the influence of the arebipolar electric field that is consistent with the distributions themselves. 3189

Comparison of the effects of wave-particle interactions and the kinetic suprathermal electron population on the acceleration of the solar wind

“…(5), we assume that the inward propagating waves constitute only 2.4 × 10 −6 of the total wave power at 1 R (solar radius). Even with such a small ratio of e − /e + near the corona, the presence of these sunward propagating waves have been shown to lead to double-peaked proton velocity distributions in the solar wind (Tam & Chang 1999a). The reason for the formation of the non-thermal feature is as follows.…”

“…Therefore, in general, more wave power is available to the helium ions than to the protons, at least in the observed regimes (0.3-1 AU). Extrapolating the power spectrum to distances close to the sun, Tam & Chang (1999a) have shown that the kinetic waveparticle interactions in general transfer more energy to a helium ion than to a proton. Although the energy is mainly transferred into the transverse direction, it converts into the field-aligned direction downstream in the solar wind due to the mirror effect, leading to a preferential acceleration of the helium ions.…”

“…The combined effects of ion cyclotron resonant heating and the suprathermal electron population have been considered in a solar wind study by Tam & Chang (1999a). The study was the first to describe the global kinetic evolution and acceleration of the fast solar wind under the influence of the wave-particle interactions, Coulomb collisions, and an ambipolar electric field that was consistent with the particle distributions themselves.…”

“…Wave-particle interactions have been considered as a possible solar wind heating mechanism, and their effects have been studied by a number of authors (e.g. Hollweg & Turner 1978;Dusenbery & Hollweg 1981;Marsch et al 1982c;Isenberg 1984;Leer et al 1992;Hu et al 1997;Czechowski et al 1998;Cranmer et al 1999b;Hu & Habbal 1999;Li et al 1999;Tam & Chang 1999a;Isenberg et al 2000;Cranmer 2001;Gary et al 2001;Liewer et al 2001;Tam & Chang 2001;Tu & Marsch 2001;Vocks & Marsch 2001). Experimentally, there has been increasing evidence suggesting that wave-particle interactions play a significant role in the evolution and acceleration of the solar wind.…”

Mode-coupling of low-frequency electromagnetic waves in dusty plasmas with temperature anisotropy

“…29,30 However, kinetic approaches to the study of the solar wind plasmas which include the charged dust particles as one of the plasma components are not easily found. That was one of the motivations of our recent publications on the subject of dusty plasmas, particularly of Ref.…”