2014
Vlasov simulations of Kinetic Alfven Waves at proton kinetic scales
Publication
Publication
Physics of Plasmas , Volume 21
Kinetic Alfv ́en waves represent an important subject in space plasma physics, since they are
thought to play a crucial role in the development of the turbulent energy cascade in the solar
wind plasma at short wavelengths (of the order of the proton inertial length d p and beyond). A full
understanding of the physical mechanisms which govern the kinetic plasma dynamics at these scales
can provide important clues on the problem of the turbulent dissipation and heating in collisionless
systems. In this paper, hybrid Vlasov-Maxwell simulations are employed to analyze in detail the
features of the kinetic Alfv ́en waves at proton kinetic scales, in typical conditions of the solar
wind environment. In particular, linear and nonlinear regimes of propagation of these fluctuations
have been investigated in a single-wave situation, focusing on the physical processes of collisionless
Landau damping and wave-particle resonant interaction. Interestingly, since for wavelengths close
to d p and proton plasma beta β of order unity the kinetic Alfv ́en waves have small phase speed
compared to the proton thermal velocity, wave-particle interaction processes produce significant
deformations in the core of the particle velocity distribution, appearing as phase space vortices and
resulting in flat-top velocity profiles. Moreover, as the Eulerian hybrid Vlasov-Maxwell algorithm
allows for a clean almost noise-free description of the velocity space, three-dimensional plots of
the proton velocity distribution help to emphasize how the plasma departs from the Maxwellian
configuration of thermodynamic equilibrium due to nonlinear kinetic effects.
Additional Metadata | |
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AIP | |
doi.org/10.1063/1.4901583 | |
Physics of Plasmas | |
Organisation | Multiscale Dynamics |
Vasconez, C. L., Valentini, F., Camporeale, E., & Veltri, P. (2014). Vlasov simulations of Kinetic Alfven Waves at proton kinetic scales. Physics of Plasmas, 21. doi:10.1063/1.4901583 |