PLASMA ACCELERATION ON MULTISCALE TEMPORAL VARIATIONS OF ELECTRIC AND MAGNETIC FIELDS DURING SUBSTORM DIPOLARIZATION IN THE EARTH’S MAGNETOTAIL
Magnetic field dipolarizations are often observed in the magnetotail during substorms. These generally include three temporal scales: (1)
actual dipolarization when the normal magnetic field changes during several minutes from minimum to maximum level; (2) sharp Bz
bursts (pulses) interpreted as the passage of multiple dipolarization fronts with characteristic time scales < 1 min, and (3) bursts of electric
and magnetic fluctuations with frequencies up to electron gyrofrequency occurring at the smallest time scales (≤ 1 s). We present a
numerical model where the contributions of the above processes (1)-(3) in particle acceleration are analyzed. It is shown that these processes
have a resonant character at different temporal scales. While O+ ions are more likely accelerated due to the mechanism (1), H+
ions (and to some extent electrons) are effectively accelerated due to the second mechanism. High-frequency electric and magnetic fluctuations
accompanying magnetic dipolarization as in (3) are also found to efficiently accelerate electrons.
In this paper software package for numerical modeling of transformation and propagation of internal gravity waves (IGW) in the World Ocean is presented. Short overview of implemented numerical models is given. They are: extended nonlinear evolutionary equation of Korteveg-de-Vries type with combined nonlinearity with variable coefficients (Gardner equation) and ray model reproducing the effect of refraction in an IGW package. The developed software package is unique and topical for this class of geophysical applications. Description of user interface and main working modes of the software are presented.
A nonstationary problem of a viscous weakly compressible heat-conducting liquid flow in a two-dimensional channel with small periodic (fast oscillating) irregularities on the heated walls is considered for large Reynolds numbers. An asymptotic solution with double-deck structure of the boundary layer and unperturbed Poiseuille core flow is obtained. The results of numerical modeling of heat transfer and investigation of the influence of the thermal expansion coeffcient on the f;ow behavior in the near-wall region are presented.
The physical-mathematical model of the sensors block of space radiation fluxes parameters monitoring module has been developed. The simulation of the sensors block output has been carried out using the series of the spectra representing space radiation spectra at different spaceship orbits in different phases of the solar activity cycle. The optimisation of the sensors block of space radiation fluxes parameters monitoring module has been carried out based on the simulation results.
Purpose: Numerical modeling of internal baroclinic disturbances of different shapes in a model lake with variable depth, analysis of velocity field of wave-induced current, especially in the near-bed layer.
Approach: The study is carried out with the use of numerical full nonlinear nonhydrostatic model for stratified fluid.
Findings: The full nonlinear numerical modeling of internal wave dynamics in a stratified lake is carried out. The calculated distributions of near-bed velocities are analyzed; the significance of 3D effects for the velocity fields is emphasized; the regions of maximal (where internal waves are the main driving factor for sediment resuspension and erosion processes on the bed) and minimal velocities are marked out.
Originality: The results are new and can have practical application for many applied problems, especially ecological and economical, concerned with the processes of propagation of natural and anthropogenic pollutions in natural basins and the investigation of water quality, as well as with influence upon engineering structures and sediment transport.
A model for organizing cargo transportation between two node stations connected by a railway line which contains a certain number of intermediate stations is considered. The movement of cargo is in one direction. Such a situation may occur, for example, if one of the node stations is located in a region which produce raw material for manufacturing industry located in another region, and there is another node station. The organization of freight traﬃc is performed by means of a number of technologies. These technologies determine the rules for taking on cargo at the initial node station, the rules of interaction between neighboring stations, as well as the rule of distribution of cargo to the ﬁnal node stations. The process of cargo transportation is followed by the set rule of control. For such a model, one must determine possible modes of cargo transportation and describe their properties. This model is described by a ﬁnite-dimensional system of diﬀerential equations with nonlocal linear restrictions. The class of the solution satisfying nonlocal linear restrictions is extremely narrow. It results in the need for the “correct” extension of solutions of a system of diﬀerential equations to a class of quasi-solutions having the distinctive feature of gaps in a countable number of points. It was possible numerically using the Runge–Kutta method of the fourth order to build these quasi-solutions and determine their rate of growth. Let us note that in the technical plan the main complexity consisted in obtaining quasi-solutions satisfying the nonlocal linear restrictions. Furthermore, we investigated the dependence of quasi-solutions and, in particular, sizes of gaps (jumps) of solutions on a number of parameters of the model characterizing a rule of control, technologies for transportation of cargo and intensity of giving of cargo on a node station.
Event logs collected by modern information and technical systems usually contain enough data for automated process models discovery. A variety of algorithms was developed for process models discovery, conformance checking, log to model alignment, comparison of process models, etc., nevertheless a quick analysis of ad-hoc selected parts of a journal still have not get a full-fledged implementation. This paper describes an ROLAP-based method of multidimensional event logs storage for process mining. The result of the analysis of the journal is visualized as directed graph representing the union of all possible event sequences, ranked by their occurrence probability. Our implementation allows the analyst to discover process models for sublogs defined by ad-hoc selection of criteria and value of occurrence probability
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.