Quantification of the Cross-helicity Turbulent Cascade in Compressible MHD Simulations

Montagud-Camps, Victor; Hellinger, Petr; Verdini, A.; Papini, Emanuele; Franci, Luca; Landi, Simone

doi:10.3847/1538-4357/ac9281

Cited by 4 publications

(3 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The presence of the ambient magnetic field induces a strong anisotropy similar to that observed in 3D MHD simulations (Verdini et al 2015;Montagud-Camps et al 2022), even though the KHM equation is only very weakly dependent on B 0 (as clearly seen in its equivalent form, Eq. (3) of Hellinger et al 2021a).…”

Section: Discussionsupporting

confidence: 56%

“…The spectral properties of the simulated system are similar to those in previous works (Markovskii & Vasquez 2011;Franci et al 2018b). We concentrated our analysis of turbulence on the KHM equation (in the form that can be easily calculated using the fast Fourier transform Banerjee & Galtier 2017;Hellinger et al 2021a;Montagud-Camps et al 2022). The KHM results show how turbulence evolves from large-scale zero-cross helicity Alfvénic-like fluctuation.…”

Section: Discussionmentioning

confidence: 99%

“…More work is needed with a better separation between the injection (energy containing) range and the scale of the pressure-strain coupling. We presented one case study of plasma turbulence; more simulations are necessary to assess the role of the amplitude of turbulent fluctuations δB/B 0 and plasma betas, as well as the crosshelicity (Montagud-Camps et al 2022).…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Anisotropy of plasma turbulence at ion scales: Hall and pressure–strain effects

Hellinger,

Verdini,

Montagud-Camps

et al. 2024

A&A

Self Cite

View full text Add to dashboard Cite

We investigated the properties of plasma turbulence at ion scales in the solar wind context. We concentrated on the behaviour of the Hall physics and the pressure strain interaction and their anisotropy owing to the ambient magnetic field. We studied the results of a three-dimensional hybrid simulation of decaying plasma turbulence using the K\'arm\'an-Howarth-Monin (KHM) equation, which quantifies different turbulent processes. The isotropised KHM analysis shows that kinetic plus magnetic (kinetic+magnetic) energy decays at large scales; this energy cascades from large to small scales via the magneto-hydrodynamic non-linearity that is partly continued via the Hall coupling around the ion scales. The cascading kinetic+magnetic energy is partly dissipated at small scales via resistive dissipation. This standard dissipation is complemented by the pressure-strain interaction, which plays the role of an effective dissipation mechanism and starts to act at relatively large scales. The pressure--strain interaction has two components, compressive and incompressive. Compressive interaction is connected with the velocity dilatation, which mostly reversibly exchanges kinetic+magnetic and internal energies. Incompressive interaction mostly irreversibly converts the kinetic+magnetic energy to internal energy. The compressive effects lead to important oscillations of the turbulence properties, but the compressibility is strongly reduced when averaged over a time period spanning a few periods of the oscillations. The ambient magnetic field induces a strong spectral anisotropy. The turbulent fluctuations exhibit larger scales along the magnetic field compared to the perpendicular directions. The KHM results show the corresponding anisotropy of turbulent processes: their characteristic scales shift to larger scales in the quasi-parallel direction with respect to the ambient magnetic field compared to the quasi-perpendicular direction. This anisotropy is weak at large scales owing to the initial isotropic spectrum, and becomes progressively stronger at small scales.

show abstract

Section: Discussionsupporting

confidence: 56%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Anisotropy of plasma turbulence at ion scales: Hall and pressure–strain effects

Hellinger,

Verdini,

Montagud-Camps

et al. 2024

A&A

Self Cite

View full text Add to dashboard Cite

show abstract

Helios 2 observations of solar wind turbulence decay in the inner heliosphere

Sorriso‐Valvo¹,

Marino²,

Foldes³

et al. 2023

A&A

View full text Add to dashboard Cite

Aims. A linear scaling of the mixed third-order moment of the magnetohydrodynamic (MHD) fluctuations is used to estimate the energy transfer rate of the turbulent cascade in the expanding solar wind. Methods. In 1976, the Helios 2 spacecraft measured three samples of fast solar wind originating from the same coronal hole, at different distances from the Sun. Along with the adjacent slow solar wind streams, these intervals represent a unique database for studying the radial evolution of turbulence in samples of undisturbed solar wind. A set of direct numerical simulations of the MHD equations performed with the Lattice-Boltzmann code FLAME was also used for interpretation. Results. We show that the turbulence energy transfer rate decays approximately as a power law of the distance and that both the amplitude and decay law correspond to the observed radial temperature profile in the fast wind case. Results from MHD numerical simulations of decaying MHD turbulence show a similar trend for the total dissipation, suggesting an interpretation of the observed dynamics in terms of decaying turbulence and that multi-spacecraft studies of the solar wind radial evolution may help clarify the nature of the evolution of the turbulent fluctuations in the ecliptic solar wind.

show abstract

Rugged magneto-hydrodynamic invariants in weakly collisional plasma turbulence: Two-dimensional hybrid simulation results

Hellinger,

Montagud-Camps

2024

A&A

View full text Add to dashboard Cite

We investigated plasma turbulence in the context of solar wind. We concentrated on properties of ideal second-order magneto-hydrodynamic (MHD) and Hall MHD invariants. We studied the results of a two-dimensional hybrid simulation of decaying plasma turbulence with an initial large cross helicity and a negligible magnetic helicity. We investigated the evolution of the combined energy and the cross, kinetic, mixed, and magnetic helicities. For the combined (kinetic plus magnetic) energy and the cross, kinetic, and mixed helicities, we analysed the corresponding K\'arm\'an-Howarth-Monin (KHM) equation in the hybrid (kinetic proton and fluid electron) approximation. The KHM analysis shows that the combined energy decays at large scales. At intermediate scales, this energy cascades (from large to small scales) via the MHD non-linearity and this cascade partly continues via Hall coupling to sub-ion scales. The cascading combined energy is transferred (dissipated) to the internal energy at small scales via the resistive dissipation and the pressure-strain effect. The Hall term couples the cross helicity with the kinetic one, suggesting that the coupled invariant, referred to here as the mixed helicity, is a relevant turbulence quantity. However, when analysed using the KHM equations, the kinetic and mixed helicities exhibit very dissimilar behaviours to that of the combined energy. On the other hand, the cross helicity, in analogy to the energy, decays at large scales, cascades from large to small scales via the MHD+Hall non-linearity, and is dissipated at small scales via the resistive dissipation and the cross-helicity equivalent of the pressure-strain effect. In contrast to the combined energy, the Hall term is important for the cross helicity over a wide range of scales (even well above ion scales). In contrast, the magnetic helicity is scantily generated through the resistive term and does not exhibit any cascade.

show abstract

Quantification of the Cross-helicity Turbulent Cascade in Compressible MHD Simulations

Cited by 4 publications

References 50 publications

Anisotropy of plasma turbulence at ion scales: Hall and pressure–strain effects

Anisotropy of plasma turbulence at ion scales: Hall and pressure–strain effects

Helios 2 observations of solar wind turbulence decay in the inner heliosphere

Rugged magneto-hydrodynamic invariants in weakly collisional plasma turbulence: Two-dimensional hybrid simulation results

Contact Info

Product

Resources

About