High-Resolution Hybrid Simulations of Kinetic Plasma Turbulence at Proton Scales

Franci, Luca; Landi, Simone; Matteini, Lorenzo; Verdini, A.; Hellinger, Petr

doi:10.1088/0004-637x/812/1/21

Cited by 117 publications

(184 citation statements)

References 109 publications

(156 reference statements)

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“…The electric field is strongly coupled to the velocity spectrum at large scales, consistently with the generalized Ohm's law (Franci et al 2015a) and solar wind observations. Moreover, it keeps following the magnetic field spectrum as the velocity fluctuations start dropping just above the ion scales.…”

Section: Discussionsupporting

confidence: 78%

“…The 1D omnidirectional spectra recover several spectral indices found in larger 2D HPIC simulations with similar initial conditions and plasma parameters (Franci et al 2015a(Franci et al , 2015b.…”

Section: Discussionsupporting

confidence: 58%

“…The maximum corresponds to about t 15 NL , which is of the same order as what is observed in previous 2D simulations using a very similar setup (Franci et al 2015a). With the peak in J rms typically being regarded as an indicator of the maximum turbulent activity (Mininni & Pouquet 2009), the analysis of the spectral properties in Section 3.2 will be performed at = t t .…”

Section: Time Evolution and Development Of A Turbulent Cascadementioning

confidence: 62%

“…In this section, we directly compare the results from the present 3D simulation with those of the 2D HPIC simulation already discussed in Franci et al (2015aFranci et al ( , 2015b. The initial conditions are quite similar, since they are both initialized with In Figure 6, we show the magnetic field structures in real space.…”

Section: Comparison With the 2d Casementioning

confidence: 86%

“…In our 3D run, they look strongly coupled to the magnetic fluctuations. Note that the indices -3 2 and -5 3 are found for the velocity and magnetic fluctuations in 2D HPIC simulations with an out-of-plane mean field (Franci et al 2015a(Franci et al , 2015b and in weakly compressible 3D MHD simulations with no mean field ). This suggests that only a weak Alfvénic coupling is achieved in the solar wind, possibly because of the valueB B 1 rms 0…”

Section: Discussionmentioning

confidence: 98%

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Solar Wind Turbulent Cascade from MHD to Sub-ion Scales: Large-size 3D Hybrid Particle-in-cell Simulations

Franci

Landi

Verdini

et al. 2018

ApJ

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Properties of the turbulent cascade from fluid to kinetic scales in collisionless plasmas are investigated by means of large-size 3D hybrid (fluid electrons, kinetic protons) particle-in-cell simulations. Initially isotropic Alfvénic fluctuations rapidly develop a strongly anisotropic turbulent cascade, mainly in the direction perpendicular to the ambient magnetic field. The omnidirectional magnetic field spectrum shows a double power-law behavior over almost two decades in wavenumber, with a Kolmogorov-like index at large scales, a spectral break around ion scales, and a steepening at sub-ion scales. Power laws are also observed in the spectra of the ion bulk velocity, density, and electric field, at both magnetohydrodynamic (MHD) and kinetic scales. Despite the complex structure, the omnidirectional spectra of all fields at ion and sub-ion scales are in remarkable quantitative agreement with those of a 2D simulation with similar physical parameters. This provides a partial, a posteriori validation of the 2D approximation at kinetic scales. Conversely, at MHD scales, the spectra of the density and of the velocity (and, consequently, of the electric field) exhibit differences between the 2D and 3D cases. Although they can be partly ascribed to the lower spatial resolution, the main reason is likely the larger importance of compressible effects in the full 3D geometry. Our findings are also in remarkable quantitative agreement with solar wind observations.

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Section: Discussionsupporting

confidence: 78%

Section: Discussionsupporting

confidence: 58%

Section: Time Evolution and Development Of A Turbulent Cascadementioning

confidence: 62%

Section: Comparison With the 2d Casementioning

confidence: 86%

Section: Discussionmentioning

confidence: 98%

See 3 more Smart Citations

Solar Wind Turbulent Cascade from MHD to Sub-ion Scales: Large-size 3D Hybrid Particle-in-cell Simulations

Franci

Landi

Verdini

et al. 2018

ApJ

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Observations of turbulence in a Kelvin‐Helmholtz event on 8 September 2015 by the Magnetospheric Multiscale mission

et al. 2016

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Spatial and high‐time‐resolution properties of the velocities, magnetic field, and 3‐D electric field within plasma turbulence are examined observationally using data from the Magnetospheric Multiscale mission. Observations from a Kelvin‐Helmholtz instability (KHI) on the Earth's magnetopause are examined, which both provides a series of repeatable intervals to analyze, giving better statistics, and provides a first look at the properties of turbulence in the KHI. For the first time direct observations of both the high‐frequency ion and electron velocity spectra are examined, showing differing ion and electron behavior at kinetic scales. Temporal spectra exhibit power law behavior with changes in slope near the ion gyrofrequency and lower hybrid frequency. The work provides the first observational evidence for turbulent intermittency and anisotropy consistent with quasi two‐dimensional turbulence in association with the KHI. The behavior of kinetic‐scale intermittency is found to have differences from previous studies of solar wind turbulence, leading to novel insights on the turbulent dynamics in the KHI.

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Generalized Ohm's Law Decomposition of the Electric Field in Magnetosheath Turbulence: Magnetospheric Multiscale Observations

Stawarz

Parashar

Matteini

et al. 2020

Preprint

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Decomposing the electric field (E) into the contributions from generalized Ohm's law provides key insight into both nonlinear and dissipative dynamics across the full range of scales within a plasma. Using high-resolution, multispacecraft measurements of three intervals in Earth's magnetosheath from the Magnetospheric Multiscale mission, the influence of the magnetohydrodynamic, Hall, electron pressure, and electron inertia terms from Ohm's law, as well as the impact of a finite electron mass, on the turbulent E spectrum are examined observationally for the first time. The magnetohydrodynamic, Hall, and electron pressure terms are the dominant contributions to E over the accessible length scales, which extend to scales smaller than the electron gyroradius at the greatest extent, with the Hall and electron pressure terms dominating at sub-ion scales. The strength of the nonideal electron pressure contribution is stronger than expected from linear kinetic Alfvén waves and a partial antialignment with the Hall electric field is present, linked to the relative importance of electron diamagnetic currents in the turbulence. The relative contribution of linear and nonlinear electric fields scale with the turbulent fluctuation amplitude, with nonlinear contributions playing the dominant role in shaping E for the intervals examined in this study. Overall, the sum of the Ohm's law terms and measured E agree to within ∼20% across the observable scales. These results both confirm general expectations about the behavior of E in turbulent plasmas and highlight features that should be explored further theoretically. Plain Language Summary Complex turbulent motions are observed in plasmas throughout the Universe and act to transfer energy from large-scale fluctuations to small-scale fluctuations, which can be more easily dissipated into the thermal energy of the particles. Electric fields in these plasmas play a central role in enabling the exchange of energy between the magnetic field and the motion of the charged particles and are, therefore, important for disentangling the complex nonlinear dynamics and dissipative processes. Using cutting-edge, high-resolution, multispacecraft measurements from NASA's Magnetospheric Multiscale mission, we decompose the electric field in Earth's turbulent magnetosheath into the various terms from generalized Ohm's law, which governs the behavior of the electric field across the wide range of length scales in the plasma. The results confirm a number of general expectations about the relative behavior of the terms in Ohm's law, as well as highlight several new features that are significant for understanding the nonlinear behavior and turbulent dissipation at different scales within the plasma.

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High-Resolution Hybrid Simulations of Kinetic Plasma Turbulence at Proton Scales

Cited by 117 publications

References 109 publications

Solar Wind Turbulent Cascade from MHD to Sub-ion Scales: Large-size 3D Hybrid Particle-in-cell Simulations

Solar Wind Turbulent Cascade from MHD to Sub-ion Scales: Large-size 3D Hybrid Particle-in-cell Simulations

Observations of turbulence in a Kelvin‐Helmholtz event on 8 September 2015 by the Magnetospheric Multiscale mission

Generalized Ohm's Law Decomposition of the Electric Field in Magnetosheath Turbulence: Magnetospheric Multiscale Observations

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