Cascade models of anisotropic turbulence in magnetized plasma of solar wind
Abstract
The solar wind plasma is modeled as a collection of discrete domains, each possessing local rotational symmetry about its domain-mean magnetic field. Based on this partial symmetry, we construct cascade models governed by the nonlinear and Alfvénic time scales. We introduce a stochastic renewal process with a bimodal waiting-time distribution determined by these two time scales. This process yields a two-branch renormalization solution for the total energy: a statistically robust branch with an Iroshnikov-Kraichnan-like k−3/2 spectrum and a statistically marginal branch with a Kolmogorov-like k−5/3 spectrum. Whenever energy-flux fluctuations become supercritical, the system selects the faster of the two available cascade rates, thereby preventing flux accumulation. During solar wind expansion, the system undergoes a dynamical first-order phase transition from the slow k−3/2 cascade to the fast k−5/3 cascade, with switchbacks accelerating the transition. The mixing of subcritical and supercritical domains in raw spacecraft measurements produces an apparent decoupling of the velocity and magnetic-field spectral indices. Incorporating a magnetic helicity cascade slaved to the energy cascade, we show that the large-scale spectra decouple into k−3/4 magnetic and k−3/2 kinetic spectra. For switchbacks inside the upper solar corona, the corresponding large-scale spectra instead decouple into k−2/3 magnetic and k−5/3 kinetic spectra. Data from Voyager, Ulysses, Helios, Wind, and PSP confirm the spectral signatures across heliospheric regions spanning heliocentric distances from 0.056 to 140 AU.
Related
- Effects of Alfvénicity on the compressible energy cascade in magnetohydrodynamic solar-wind turbulence: Evidence from Parker Solar Probe, Solar Orbiter, and WIND observations
- Effects of Alfvénicity on the Compressible Energy Cascade in Magnetohydrodynamic Solar Wind Turbulence: Evidence from Parker Solar Probe, Solar Orbiter, and WIND observations
- Plasma Turbulence and Turbulent Cascade Rates at High Latitudes Using MeerKAT Radio Observations
- Ion-Scale Waves Regulated by Plasma Beta and Cross Helicity: Observational Evidence for the Helicity Barrier in Imbalanced Solar Wind Turbulence
- Scalar Dissipation Criticality in Compressible Magnetized Turbulence
BibTeX
@misc{bershadskii2026cascade,
title = {{Cascade models of anisotropic turbulence in magnetized plasma of solar wind}},
author = {A. Bershadskii},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2609.10418},
eprint = {2609.10418},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.10418},
}
RIS
TY - UNPB
TI - Cascade models of anisotropic turbulence in magnetized plasma of solar wind
AU - A. Bershadskii
PY - 2026
DA - 2026/10/29
PB - arXiv
DO - 10.48550/arxiv.2609.10418
UR - https://arxiv.org/abs/2609.10418
AB - The solar wind plasma is modeled as a collection of discrete domains, each possessing local rotational symmetry about its domain-mean magnetic field. Based on this partial symmetry, we construct cascade models governed by the nonlinear and Alfvénic time scales. We introduce a stochastic renewal process with a bimodal waiting-time distribution determined by these two time scales. This process yields a two-branch renormalization solution for the total energy: a statistically robust branch with an Iroshnikov-Kraichnan-like k^−3/2 spectrum and a statistically marginal branch with a Kolmogorov-like k^−5/3 spectrum. Whenever energy-flux fluctuations become supercritical, the system selects the faster of the two available cascade rates, thereby preventing flux accumulation. During solar wind expansion, the system undergoes a dynamical first-order phase transition from the slow k^−3/2 cascade to the fast k^−5/3 cascade, with switchbacks accelerating the transition. The mixing of subcritical and supercritical domains in raw spacecraft measurements produces an apparent decoupling of the velocity and magnetic-field spectral indices. Incorporating a magnetic helicity cascade slaved to the energy cascade, we show that the large-scale spectra decouple into k^−3/4 magnetic and k^−3/2 kinetic spectra. For switchbacks inside the upper solar corona, the corresponding large-scale spectra instead decouple into k^−2/3 magnetic and k^−5/3 kinetic spectra. Data from Voyager, Ulysses, Helios, Wind, and PSP confirm the spectral signatures across heliospheric regions spanning heliocentric distances from 0.056 to 140 AU.
ER -