0471449 - ASÚ 2017 RIV US eng J - Journal Article
Hellinger, Petr - Trávníček, Pavel M.
Proton Heating by Pick-up Ion Driven Cyclotron Waves in the Outer Heliosphere: Hybrid Expanding Box Simulations.
Astrophysical Journal. Roč. 832, č. 1 (2016), 32/1-32/7. ISSN 0004-637X. E-ISSN 1538-4357
Institutional support: RVO:67985815
Keywords : solar wind * instabilities * plasmas
Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics
Impact factor: 5.533, year: 2016

Using a one-dimensional hybrid expanding box model, we investigate properties of the solar wind in the outer heliosphere. We assume a proton-electron plasma with a strictly transverse ambient magnetic field and, aside from the expansion, we take into account the influence of a continuous injection of cold pick-up protons through the charge-exchange process between the solar wind protons and hydrogen of interstellar origin. The injected cold pick-up protons form a ring distribution function, which rapidly becomes unstable, and generate Alfven cyclotron waves. The Alfvwn cyclotron waves scatter pick-up protons to a spherical shell distribution function that thickens over that time owing to the expansion-driven cooling. The Alfvwn cyclotron waves heat solar wind protons in the perpendicular direction (with respect to the ambient magnetic field) through cyclotron resonance. At later times, the Alfven cyclotron waves become parametrically unstable and the generated ion-acoustic waves heat protons in the parallel direction through Landau resonance. The resulting heating of the solar wind protons is efficient on the expansion timescale.
Permanent Link: http://hdl.handle.net/11104/0268835