In 3D turbulent flows of a rotating system, where the Coriolis force prevails over the inertia in dynamics, formation of the columnar vortices takes place that is observed both experimentally [1] and numerically [2]. They are large-scale coherent flows that are homogeneous along the axis of rotation. Our work is about to build analytical model describing how axisymmetric vortex flow supports itself by absorbing inertial waves. We consider the following pumping mode: inertial waves reach the vortex from the periphery of system, where turbulence is excited. In the limits of short wavelengths and low viscosity we show that quasi-monochromatic wave that enters in the vortex transmits its energy and momentum only in the narrow vicinity of its critical layer [3] formed by an average shear flow. In our model we determine the Reynolds shear stress component averaged over inertial wave ensemble that sets the velocity profile of vortex [4].

[1] D.D. Tumachev, A.A. Levchenko, S.S. Vergeles, S.V. Filatov, Observation of a large stable anticyclone in rotating turbulence, PoF, 36(12), 126620 (2024).
[2] Seshasayanan, K. & Alexakis, A. Condensates in rotating turbulent flows. JFM, 841, 434–462 (2018).
[3] Haynes, P., 2015. Critical Layers. In: G. R. North et al., Encyclopedia of Atmospheric Sciences, 2nd edition, Vol 2.
[4] I.V. Kolokolov, L.L. Ogorodnikov, and S.S. Vergeles, Structure of coherent columnar vortices in three-dimensional rotating turbulent flow, Phys. Rev. Fluids 5, 034604 (2020).

We investigate analytically and numerically the statistical properties of the dynamics of rigid spherical particles with neutral buoyancy. The particles are placed in a turbulent flow with a strong shear component. As a simple model, we consider the shear flow of an axisymmetric vortex with turbulent fluctuations and calculate the particle distribution from the distance to the vortex center. We present quantitative results obtained within the framework of a point particle model with fluctuations that are correlated in time.

The mechanisms of surface relief formation on bulk copper samples under the influence of UV laser pulses (duration 10 ns, wavelength 355 nm) in the mode of heating to temperatures below the melting temperature have been investigated. It has been experimentally established that during irradiation at energy densities of 0.60-1.05 J/cm2 a characteristic system of protrusions/depressions, the height/depth of which reaches up to 500 nm, is formed on the surface of the samples in local areas near grain boundaries. By methods of optical profilometry, confocal scanning laser microscopy and transmission electron microscopy the deformation nature of the formed relief was established. The thin near-surface layer near grain boundaries shows traces of plastic deformation development: nanoscale twin plates, dislocations and low-angle dislocation boundaries. Molecular dynamic modeling has shown that the main physical reason for the development of the considered relief is the anisotropy of thermal expansion of differently oriented grains (crystallites) during cyclic heating to pre-melt temperatures. It is established that thermomechanical stresses arising in the near-surface layer exceed the yield strength of the material, which leads to irreversible plastic deformation. The amplification of structural changes is shown to increase with both the energy density and the number of pulses. The results obtained are important for understanding the mechanisms of metal structure degradation under cyclic pulse thermomechanical loading and can be used, in particular, to develop methods for increasing the operational durability of metal optics.

Неласов И.В., Манохин С.С., Колобов Ю.Р., Жаховский В.В., Перов Е.А., Петров Ю.В., Хомич Ю.В., Малинский Т.В., Иногамов Н.А., Рогалин В.Е. // ЖЭТФ. – 2025. – Т. 167. – № 6. Zhurnal Experimentalnoi i Teoreticheskoi Fiziki Vol. 167 (6) (2025).

We investigate the spatially-resolved dynamics of the collective amplitude Schmid-Higgs (SH) mode in disordered s-wave superconductors and fermionic superfluids. By analyzing the analytic structure of the zero-temperature SH susceptibility in the complex frequency plane, we find that when the coherence length greatly exceeds the mean free path: (i) the SH response at fixed wave vectors exhibits late-time oscillations decaying as 1/t2 with frequency 2Δ, where Δ is the superconducting gap; (ii) sub-diffusive oscillations with a dynamical exponent z=4 emerge at late times and large distances; and (iii) spatial oscillations at fixed frequency decay exponentially, with a period that diverges as the frequency approaches 2Δ from above. When the coherence length is comparable to the mean free path, additional exponentially-decaying oscillations at fixed wave vectors appear with frequency above 2Δ. Furthermore, we show that the SH mode induces an extra peak in the third-harmonic generation current at finite wave-vectors. The frequency of this peak is shifted from the conventional resonance at Δ, thereby providing an unambiguous signature of order parameter amplitude dynamics.

Optimization of the mean completion time of random processes by restart is a subject of active theoretical research in statistical physics and has long found practical application in computer science. Meanwhile, one of the key issues remains largely unsolved: how to construct a restart strategy for a process whose detailed statistics are unknown to ensure that the expected completion time will reduce? Addressing this query here we propose several constructive criteria for the effectiveness of various protocols of non-instantaneous restart in the mean completion time problem and in the success probability problem. Being expressed in terms of a small number of easily estimated statistical characteristics of the original process (MAD, median completion time, low-order statistical moments of completion time), these criteria allow informed restart decision based on partial information.

Both Markovian and arbitrary residence time distributions are considered. The comparison of analytical predictions with the case of a time-decorrelated process shows that correlations can both decrease and increase the corresponding expected waiting time. Besides, the comparison of exponential, subexponential, and heavy-tailed models characterized by equal probabilities to observe the event of interest demonstrates that a faster decrease in the residence time probability density implies a shorter expected waiting time. Interestingly, irrespective of the details of a particular model for both discrete- and continuous-time jump processes considered here, the random waiting time becomes exponentially distributed in the long-time limit, thus, showing remarkable universality.