Počet záznamů: 1  

Protons and alpha particles in the expanding solar wind: Hybrid simulations

  1. 1. 0425964 - UFA-U 2014 RIV US eng J - Článek v odborném periodiku
    Hellinger, Petr - Trávníček, Pavel M.
    Protons and alpha particles in the expanding solar wind: Hybrid simulations.
    Journal of Geophysical Research: Space Physics. Roč. 118, č. 9 (2013), s. 5421-5430 ISSN 2169-9380
    Institucionální podpora: RVO:68378289
    Klíčová slova: solar wind * ion energetics
    Kód oboru RIV: BL - Fyzika plazmatu a výboje v plynech
    Impakt faktor: 3.440, rok: 2013
    http://onlinelibrary.wiley.com/doi/10.1002/jgra.50540/abstract

    We present results of a twodimensional hybrid expanding box simulation of a plasma system with three ion populations, beam and core protons, and alpha particles (and fluid electrons), drifting with respect to each other. The expansion with a strictly radial magnetic field leads to a decrease of the ion perpendicular to parallel temperature ratios as well as to an increase of the ratio between the ion relative velocities and the local Alfven velocity creating a free energy for many different instabilities. The system is most of the time marginally stable with respect to kinetic instabilities mainly due to the ion relative velocities; these instabilities determine the system evolution counteracting some effects of the expansion. Nonlinear evolution of these instabilities leads to large modifications of the ion velocity distribution functions. The beam protons and alpha particles are decelerated with respect to the core protons and all the populations are cooled in the parallel direction and heated in the perpendicular one. On the macroscopic level, the kinetic instabilities cause large departures of the system evolution from the double adiabatic prediction and lead to perpendicular heating and parallel cooling rates which are comparable to the heating rates estimated from the Helios observations.
    Trvalý link: http://hdl.handle.net/11104/0231748