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Title: Vlasov simulations of kinetic Alfvén waves at proton kinetic scales

Abstract

Kinetic Alfvén 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 gyro radius ρ{sub p} and/or inertial length d{sub 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 Alfvén waves at proton kinetic scales, in typical conditions of the solar wind environment (proton plasma beta β{sub p} = 1). 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{sub p} and β{sub p} ≃ 1 (for which ρ{sub p} ≃ d{sub p}) the kinetic Alfvén 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,more » 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.« less

Authors:
 [1]; ;  [1];  [2]
  1. Dipartimento di Fisica, Università della Calabria, I-87036 Cosenza (Italy)
  2. Centrum Wiskunde and Informatica, Amsterdam (Netherlands)
Publication Date:
OSTI Identifier:
22403247
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 21; Journal Issue: 11; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1070-664X
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; DISTRIBUTION; HYBRIDIZATION; LANDAU DAMPING; NONLINEAR PROBLEMS; PARTICLE INTERACTIONS; PLASMA; PROTONS; SIMULATION; SOLAR WIND; VELOCITY; WAVELENGTHS

Citation Formats

Vásconez, C. L., Observatorio Astronómico de Quito, Escuela Politécnica Nacional, Quito, Valentini, F., Veltri, P., and Camporeale, E. Vlasov simulations of kinetic Alfvén waves at proton kinetic scales. United States: N. p., 2014. Web. doi:10.1063/1.4901583.
Vásconez, C. L., Observatorio Astronómico de Quito, Escuela Politécnica Nacional, Quito, Valentini, F., Veltri, P., & Camporeale, E. Vlasov simulations of kinetic Alfvén waves at proton kinetic scales. United States. https://doi.org/10.1063/1.4901583
Vásconez, C. L., Observatorio Astronómico de Quito, Escuela Politécnica Nacional, Quito, Valentini, F., Veltri, P., and Camporeale, E. 2014. "Vlasov simulations of kinetic Alfvén waves at proton kinetic scales". United States. https://doi.org/10.1063/1.4901583.
@article{osti_22403247,
title = {Vlasov simulations of kinetic Alfvén waves at proton kinetic scales},
author = {Vásconez, C. L. and Observatorio Astronómico de Quito, Escuela Politécnica Nacional, Quito and Valentini, F. and Veltri, P. and Camporeale, E.},
abstractNote = {Kinetic Alfvén 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 gyro radius ρ{sub p} and/or inertial length d{sub 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 Alfvén waves at proton kinetic scales, in typical conditions of the solar wind environment (proton plasma beta β{sub p} = 1). 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{sub p} and β{sub p} ≃ 1 (for which ρ{sub p} ≃ d{sub p}) the kinetic Alfvén 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.},
doi = {10.1063/1.4901583},
url = {https://www.osti.gov/biblio/22403247}, journal = {Physics of Plasmas},
issn = {1070-664X},
number = 11,
volume = 21,
place = {United States},
year = {Sat Nov 15 00:00:00 EST 2014},
month = {Sat Nov 15 00:00:00 EST 2014}
}