Radiation from uniformly moving sources (Vavilov-Cherenkov effect,transition radiation,and some other phenomena)

The radiation produced by uniformly moving sources (the Vavilov-Cherenkov effect, the transition radiation, and some other phenomena) is discussed. This area of physical research originated in the Lebedev Physical Institute of the Russian Academy of Sciences and now represents an integral part of modern physics.     

Hawking radiation of a uniformly accelerating black hole

In this paper, we study the Hawking radiation via tunnelling from a uniformly accelerating black hole. Although the Bekenstein--Hawking entropy is proportional also to the area of the event horizon, the radius of it, r_{\rm H}, is a function of \theta, which leads to the difficulties in the calculation of the emission rate. In order to overcome the mathematical difficulties, we propose a new technique to calculate the emission rate and the result obtained is reasonable.     

Remarks on Hawking radiation as tunneling from a uniformly accelerating black hole

Motivated by the Hamilton-Jacobi method of Angheben et al, we investigate the Hawking tunneling radiation from a uniformly accelerating rectilinear black hole for which the horizons and entropy are functions of θ. After several coordinate transformations, we conclude that when the self-gravitational interaction and energy conservation are taken into account, the actual radiation spectrum deviates from the thermal one and the tunneling rate is the function of θ though it is still related to the change of the Bekenstein-Hawking entropy.      

Frequency up-converted radiation from a cavity moving in vacuum

We calculate the photon emission of a high finesse cavity moving in vacuum. The cavity is treated as an open system. The field initially in the vacuum state accumulates a dephasing depending on the mirrors motion when bouncing back and forth inside the cavity. The dephasing is not linearized in our calculation, so that qualitatively new effects like pulse shaping in the time domain and frequency up-conversion in the spectrum are found. Furthermore we predict the existence of a threshold above which the system should show self-sustained oscillations. Received: 10 December 1997 / Received in final form: 27 March 1998 / Accepted: 27 March 1998     

Coherent radiation from neutral molecules moving above a grating

We predict and study the effect of parametric self-induced excitation of a molecule moving above the dielectric or conducting medium with periodic grating. In this case the radiation reaction force modulates the molecular transition frequency which results in a parametric instability of dipole oscillations even from the level of quantum or thermal fluctuations. The present mechanism of instability of electrically neutral molecules is different from that of the well-known Smith-Purcell and transition radiation in which a moving charge and its oscillating image create an oscillating dipole. We show that parametrically excited molecular bunches can produce an easily detectable coherent radiation flux of up to a microwatt.     

Classical theory of radiation from a charge moving in a spiral

The radiation emission of a particle spiraling in a medium is investigated. The electric and magnetic field intensities are calculated, and an equation is obtained in integral form for the radiation spectrum. Two limiting cases are thoroughly analyzed: those of circular and rectilinear motion of the charge.Translated from Izvestiya VUZ. Fizika, No. 5, pp. 29–34, May, 1971.The authors wish to thank Professor A. F. Lubchenko for useful advice and discussions during the completion of this work.     

一类线性阻尼振子的随机共振研究

针对随机有色噪声参数激励和周期调制噪声外激励联合作用下的线性阻尼振子,利用Shapiro-Loginov公式推导了系统响应的一、二阶稳态矩的解析表达式.发现这类系统存在传统的随机共振、广义的随机共振和“真正”的随机共振;当乘性噪声强度和调制噪声强度的比值大于等于1时,系统出现随机多共振现象.通过数值计算的系统响应功率谱,验证了理论分析结果. 关键词： 随机共振 周期调制的噪声 线性阻尼振子     

Global dynamics of a vibro-impacting linear oscillator

The steady state, vibro-impacting responses of one dimensional, harmonically excited, linear oscillators are studied by using a modern dynamical systems approach allied with numerical simulation. The steady state motions are attracting sets in the system phase space and capture initial conditions in their domains of attraction. Unlike the free, harmonically excited oscillator, the phase space of a vibro-impacting system may be inhabited by many attracting sets. For example, there are sub-harmonic, multi-impact, periodic orbits and chaotic, steady state responses. In order to build a qualitative understanding of vibro-impact response, an attempt is made to build generic topological models of their phase spaces for physically significant parameter ranges. Use is made of the Poincaré section or stroboscopic mapping technique, essentially following an initial impact forwards or backwards in time to subsequent or previous impacts using a computer. The qualitative understanding gained from the analysis and simulations is discussed in an engineering context.     

On reflection of radiation from moving objects

An analytical expression for the field reflected from a nonuniformity of the velocity of a moving medium is obtained. Specific features of the reflected radiation depending on the velocity and sizes of the non-uniformity domain and on the angle of incidence of radiation relative to the direction of motion are studied. The feasibility of experimental detection of the reflected radiation is demonstrated.     

Electromagnetic radiation from a conducting tether moving in the ionosphere

Summary We set up a model to compute electromagnetic radiation associated with the motion of a conductor through a magnetized plasma. Calculations are carried out, in the framework of cold-plasma theory, for radiation near the ion cyclotron frequency. Results are applied to the TSS (Tethered Satellite System) project presently under development.

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Riassunto S’imposta il formalismo generale per il calcolo della radiazione elettromagnetica associata con il moto di un conduttore in moto attraverso un plasma magnetizzato. I calcoli sono poi fatti specificamente per la radiazione nelle vicinanze della frequenza di ciclotrone degli ioni. I risultati sono applicati ai parametri del progetto spaziale TSS (Tethered Satellite System) che è attualmente in fase di sviluppo.

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Резюме Мы предлагаем модель для вычисления электромагнитного излучения, связанного с движением проводника через намагниченныю плазму. Вычисления проводятся в рамках теории холодной плазмы для изучения вблизи ионной циклотронной частоты. Полученные результаты применяются к ТСС (связанная система спутников), проект которой разрабатывается в настояцее время.