Year: 2026
Type: article
Abstract: Solar-wind streams are turbulent and dominated by changes of the magnetic-field direction at almost constant field intensity. The time evolution of rotations undergone by the magnetic-field vector over a given timescale is modeled on the basis of the exponential Ornstein–Uhlenbeck process in a way that is consistent with in situ measurements of a nearly lognormal distribution of the magnetic-field increment magnitude normalized by the field intensity. The approach yields insights on observables related to magnetic-field rotation measurements such as level-crossing and waiting-time distributions. Large-deviation regimes are investigated in more detail. It is shown that over times longer than the correlation time, the occurrence of large rotations becomes a Poisson renewal process. The power-law component of the waiting-time distribution, over times much shorter than the correlation time, reflects the roughness of the field fluctuations. The model provides theoretical foundations for understanding the physical mechanisms governing the dynamical evolution of intermittent magnetic fields, rotational discontinuities, and current sheets in astrophysical plasma turbulence.
Source: The Astrophysical Journal
Authors: N. H. Bian, Gang Li, S. Y. Huang, A. Chian
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
OpenAlex ID: W7214935837