Transitional regime of electron resonant interaction with whistler-mode waves in inhomogeneous space plasma.

Resonances with electromagnetic whistler-mode waves are the primary driver for the formation and dynamics of energetic electron fluxes in various space plasma systems, including shock waves and planetary radiation belts. The basic and most elaborated theoretical framework for the description of the integral effect of multiple resonant interactions is the quasilinear theory, which operates through electron diffusion in velocity space. The quasilinear diffusion rate scales linearly with the wave intensity, D_{QL}∼B_{w}^{2}, which should be small enough to satisfy the applicability criteria of this theory.

Superfast ion scattering by solar wind discontinuities.

Large-amplitude fluctuations of the solar wind magnetic field can scatter energetic ions. One of the main contributions to these fluctuations is provided by solar wind discontinuities, i.e.

Remarkable charged particle dynamics near magnetic field null lines.

The study of charged-particle motion in electromagnetic fields is a rich source of problems, models, and new phenomena for nonlinear dynamics. The case of a strong magnetic field is well studied in the framework of a guiding center theory, which is based on conservation of an adiabatic invariant-the magnetic moment. This theory ceases to work near a line on which the magnetic field vanishes-the magnetic field null line.

Probabilistic approach to nonlinear wave-particle resonant interaction.

In this paper we provide a theoretical model describing the evolution of the charged-particle distribution function in a system with nonlinear wave-particle interactions. Considering a system with strong electrostatic waves propagating in an inhomogeneous magnetic field, we demonstrate that individual particle motion can be characterized by the probability of trapping into the resonance with the wave and by the efficiency of scattering at resonance. These characteristics, being derived for a particular plasma system, can be used to construct a kinetic equation (or generalized Fokker-Planck equation) modeling the long-term evolution of the particle distribution.

Charged particle dynamics in turbulent current sheets.

We study dynamics of charged particle in current sheets with magnetic fluctuations. We use the adiabatic theory to describe the nonperturbed charged particle motion and show that magnetic field fluctuations destroy the adiabatic invariant. We demonstrate that the evolution of particle adiabatic invariant's distribution is described by a diffusion equation and derive analytical estimates of the rate of adiabatic invariant's diffusion.

Nonresonant Charged-Particle Acceleration by Electrostatic Waves Propagating across Fluctuating Magnetic Field.

In this Letter, we demonstrate the effect of nonresonant charged-particle acceleration by an electrostatic wave propagating across the background magnetic field. We show that in the absence of resonance (i.e.

Violation of adiabaticity in magnetic billiards due to separatrix crossings.

We consider dynamics of magnetic billiards with curved boundaries and strong inhomogeneous magnetic field. We investigate a violation of adiabaticity of charged particle motion in this system. The destruction of the adiabatic invariance is due to the change of type of the particle trajectory: particles can drift along the boundary reflecting from it or rotate around the magnetic field at some distance from the boundary without collisions with it.

Rapid geometrical chaotization in slow-fast Hamiltonian systems.

In this Rapid Communication we demonstrate effects of a new mechanism of adiabaticity destruction in Hamiltonian systems with a separatrix in the phase space. In contrast to the slow diffusive-like destruction typical for many systems, this new mechanism is responsible for very fast chaotization in a large phase volume. To investigate this mechanism we consider a Hamiltonian system with two degrees of freedom and with a separatrix in the phase plane of fast variables.

What you should know about patients who bring a list to their office visit.

Purpose: Little is known about patients who present a written list during a medical consultation.In this preliminary study, we sought to examine and characterize patients who use a prepared list.

Methods: The design was an open observational case-controlled study that took place at 2 urban primary care clinics.

Stability of relativistic surfatron acceleration.

In this paper we consider the surfatron acceleration of relativistic charged particles by a strong electrostatic wave propagating in a transverse direction relative to the background magnetic field. We investigate how high-frequency fluctuations of the background magnetic field affect the process of the resonant acceleration. We show that the presence of fluctuations leads to particle escape from the surfatron resonance and illustrate that fluctuations of different components of the magnetic field have quite a distinct effect on the energy gained by particles.

Directed transport in a classical lattice with a high-frequency driving.

We analyze the dynamics of a classical particle in a spatially periodic potential under the influence of a periodic in time uniform force. It was shown by S. Flach and coworkers [Phys.

Fermi acceleration in time-dependent rectangular billiards due to multiple passages through resonances.

We consider a slowly rotating rectangular billiard with moving boundaries and use canonical perturbation theory to describe the dynamics of a billiard particle. In the process of slow evolution, certain resonance conditions can be satisfied. Correspondingly, phenomena of scattering on a resonance and capture into a resonance happen in the system.

Destruction of adiabatic invariance for billiards in a strong nonuniform magnetic field.

We study a classical billiard of charged particles in a strong nonuniform magnetic field. We provide an adiabatic description for skipping motion along the boundary of the billiard. We show that a sequence of many changes of regimes of motion from skipping to motion without collisions with the boundary and back to skipping leads to destruction of the adiabatic invariance and chaotic dynamics in a large domain in the phase space.

Jumps of adiabatic invariant at the separatrix of a degenerate saddle point.

We consider a slow-fast Hamiltonian system with two degrees of freedom. One degree of freedom corresponds to slow variables, and the other one corresponds to fast variables. A characteristic ratio of the rates of change of slow and fast variables is a small parameter κ.

Resonant acceleration of charged particles in the presence of random fluctuations.

We present a quantitative theory of the nonlinear dynamics and surfatron resonant acceleration of charged particles in the presence of random fluctuations of magnetic field. We demonstrate that the surfatron mechanism of acceleration is sufficiently stable versus the influence of fluctuations and particle accelerate even in the presence of a random noise. We estimate the maximum energy which particles could gain in the course of the surfatron acceleration.

[Periodicity and quality of clinical diagnostics of protracted pneumonia in a tuberculosis clinic].

Analysis of the quality and modes of clinical diagnostics of protracted pneumonia in a tuberculosis clinic revealed the most frequent causes of this condition responsible for hyperdiagnostics of tuberculosis. These are concomitant diseases, pneumosclerosis, chronic bronchitis, fibrous transformation of the bronchial tree, complicated clinical course of pneumonia, age above 60 years, history of tuberculosis, inadequate or short-term antibiotic therapy at the initial stages of diagnostics. Motivational prerequisites for high-quality diagnostic work include compliance with standards and guidelines for the examination and management of patients suspected of having pneumonia with a view to detecting tuberculosis.

Adiabatic description of capture into resonance and surfatron acceleration of charged particles by electromagnetic waves.

We present an analytical and numerical study of the surfatron acceleration of nonrelativistic charged particles by electromagnetic waves. The acceleration is caused by capture of particles into resonance with one of the waves. We investigate capture for systems with one or two waves and provide conditions under which the obtained results can be applied to systems with more than two waves.

Directed transport in a spatially periodic harmonic potential under periodic nonbiased forcing.

Transport of a particle in a spatially periodic harmonic potential under the influence of a slowly time-dependent unbiased periodic external force is studied. The equations of motion are the same as in the problem of a slowly forced nonlinear pendulum. Using methods of the adiabatic perturbation theory we show that for a periodic external force of a general kind the system demonstrates directed (ratchet) transport in the chaotic domain on very long time intervals and obtain a formula for the average velocity of this transport.

On the absence of stable periodic orbits in domains of separatrix crossings in nonsymmetric slow-fast Hamiltonian systems.

We consider a two degree of freedom Hamiltonian system with one degree of freedom corresponding to fast motion and the other corresponding to slow motion. We assume that at frozen values of the slow variables there is a separatrix on the phase plane of the fast variables and there is a region in the phase space (the domain of separatrix crossings) where projections of phase points onto the plane of the fast variables repeatedly cross the separatrix in the process of evolution of the slow variables. Under rather general conditions, we prove that there are no stable periodic trajectories of any prescribed period inside the domain of separatrix crossings, except maybe for periodic trajectories passing anomalously close to the saddle point.

On passage through resonances in volume-preserving systems.

Resonance processes are common phenomena in multiscale (slow-fast) systems. In the present paper we consider capture into resonance and scattering on resonance in 3D volume-preserving multiscale systems. We propose a general theory of those processes and apply it to a class of kinematic models inspired by viscous Taylor-Couette flows between two counter-rotating cylinders.

[Linear tomographic scan filtration in the diagnosis of pulmonary globular and cavitary masses].

To enhance the informative value and validity of X-ray study in detecting destructive changes in infiltrates, tuberculomas, and blocked caverns, the authors treated their computed tomographic scans by linear spatial filtration and identification of equidensite fields. In this case, after treatment of an image, the phase of decay in the presence of filtrates was 14.2% and increased up to 36.

Capture into resonance in dynamics of a classical hydrogen atom in an oscillating electric field.

We consider a classical hydrogen atom in a linearly polarized electric field of slowly changing frequency. In the process of evolution, the system passes through resonances between the driving frequency and the Keplerian frequency of the electron's motion. At a resonance, a capture into the resonance can occur.

On chaotic behavior of gravitating stellar shells.

Motion of two gravitating spherical stellar shells around a massive central body is considered. Each shell consists of point particles with the same specific angular momenta and energies. In the case when one can neglect the influence of gravitation of one ("light") shell onto another ("heavy") shell ("restricted problem") the structure of the phase space is described.

Transport in a slowly perturbed convective cell flow.

We study transport properties in a simple model of two-dimensional roll convection under a slow periodic (period of order 1/ varepsilon >>1) perturbation. The problem is considered in terms of conservation of the adiabatic invariant. It is shown that the adiabatic invariant is well conserved in the system.