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| Titel |
Protons and alpha particles in the solar wind |
| VerfasserIn |
Petr Hellinger, Pavel M. Travnicek, Thierry Passot, Pierre-Louis Sulem, Lorenzo Matteini, Simone Landi |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250091686
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| Publikation (Nr.) |
 EGU/EGU2014-5990.pdf |
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| Zusammenfassung |
| We investigate energetic consequences of ion kinetic instabilitities in the solar wind
connected with beam and core protons and alpha particles drifting with respect to each other.
We compare theoretical predictions, simulations and observation results. For theoretical
prediction we assume drifting bi-Maxwellian ion populations and we calculate theoretical
quasilinear heating rates (Hellinger et al., 2013b). The nonlinear evolution of beam-core
protons, and alpha particles in the expanding solar wind we investigate using hybrid
expanding box system (Hellinger and Travnicek, 2013). The expansion leads to many
different kinetic instabilities. In the simulation 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 in agreement with theoretical expectations. On
the macroscopic level the kinetic instabilities cause large departures of the system evolution
from the double adiabatic prediction and lead to a perpendicular heating and parallel cooling
rates. The simulated heating rates are comparable to the heating rates estimated from the
Helios observations (Hellinger et al., 2013a); furthermore, the differential velocity
between core and beam protons observed by Ulysses exhibits apparent bounds which
are compatible with the theoretical constaints imposed by the linear theory for the
magnetosonic instability driven by beam-core differential velocity (Matteini et al.,
2013).
References
Hellinger, P., P. M. Travnicek, S. Stverak, L. Matteini, and M. Velli (2013a),
Proton thermal energetics in the solar wind: Helios reloaded, J. Geophys. Res.,
118, 1351–1365, doi:10.1002/jgra.50107.
Hellinger, P., T. Passot, P.-L. Sulem, and P. M. Travnicek (2013b), Quasi-linear
heating and acceleration in bi-Maxwellian plasmas, Phys. Plasmas, 20, 122306.
Hellinger, P., and P. M. Travnicek (2013), Protons and alpha particles in the
expanding solar wind: Hybrid simulations, J. Geophys. Res., 118, 5421–5430,
doi:10.1002/jgra.50540.
Matteini, L., P. Hellinger, B. E. Goldstein, S. Landi, M. Velli, and M. Neugebauer
(2013), Signatures of kinetic instabilities in the solar wind, J. Geophys. Res., 118,
2771–2782, doi:10.1002/jgra.50320. |
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