Secondary electron emission yield in the limit of low electron energy

Secondary electron emission (SEE) from solids plays an important role in many areas of science and technology.1 In recent years, there has been renewed interest in the experimental and theoretical studies of SEE. A recent study proposed that the reflectivity of very low energy electrons from solid surface approaches unity in the limit of zero electron energy2,3,4, If this was indeed the case, this effect would have profound implications on the formation of electron clouds in particle accelerators,2-4 plasma measurements with electrostatic Langmuir probes, and operation of Hall plasma thrusters for spacecraft propulsion5,6. It appears that, the proposed high electron reflectivity at low electron energies contradicts to numerous previous experimental studies of the secondary electron emission7. The goal of this note is to discuss possible causes of these contradictions.Comment: 3 pages, contribution to the Joint INFN-CERN-EuCARD-AccNet Workshop on Electron-Cloud Effects: ECLOUD'12; 5-9 Jun 2012, La Biodola, Isola d'Elba, Ital

Electromagnetic Weibel instability in intense charged particle beams with large energy anisotropy

In plasmas with strongly anisotropic distribution functions, collective instabilities may develop if there is sufficient coupling between the transverse and longitudinal degrees of freedom. Our previous numerical and theoretical studies of intense charged particle beams with large temperature anisotropy [E. A. Startsev, R. C. Davidson and H. Qin, PRSTAB, 6, 084401 (2003); Phys. Plasmas 9, 3138 (2002)] demonstrated that a fast, electrostatic, Harris-like instability develops, and saturates nonlinearly, for sufficiently large temperature anisotropy (T{sub {perpendicular}b}/T{sub {parallel}b} >> 1). The total distribution function after saturation, however, is still far from equipartitioned. In this paper the linearized Vlasov-Maxwell equations are used to investigate detailed properties of the transverse electromagnetic Weibel-type instability for a long charge bunch propagating through a cylindrical pipe of radius r{sub w}. The kinetic stability analysis is carried out for azimuthally symmetric perturbations about a two-temperature thermal equilibrium distribution in the smooth-focusing approximation. The most unstable modes are identified, and their eigenfrequencies, radial mode structure and instability thresholds are determined. The stability analysis shows that, although there is free energy available to drive the electromagnetic Weibel instability, the finite transverse geometry of the charged particle beam introduces a large threshold value for the temperature anisotropy ((T{sub {perpendicular}b}/T{sub {parallel}b}){sup Weibel} >> (T{sub {perpendicular}b}/T{sub {parallel}b}){sup Harris}) below which the instability is absent. Hence, unlike the case of an electrically neutral plasma, the Weibel instability is not expected to play as significant a role in the process of energy isotropization of intense unneutralized charged particle beams as the electrostatic Harris-type instability

Controlling Charge and Current Neutralization of an Ion Beam Pulse in a Background Plasma by Application of a Solenoidal Magnetic Field I: Weak Magnetic Field Limit

Propagation of an intense charged particle beam pulse through a background plasma is a common problem in astrophysics and plasma applications. The plasma can effectively neutralize the charge and current of the beam pulse, and thus provides a convenient medium for beam transport. The application of a small solenoidal magnetic field can drastically change the self-magnetic and self- electric fields of the beam pulse, thus allowing effective control of the beam transport through the background plasma. An analytic model is developed to describe the self-magnetic field of a finite- length ion beam pulse propagating in a cold background plasma in a solenoidal magnetic field. The analytic studies show that the solenoidal magnetic field starts to infuence the self-electric and self-magnetic fields when ωce > ωpeβb, where ωce = eβ/mec is the electron gyrofrequency, ωpe is the electron plasma frequency, and βb = Vb/c is the ion beam velocity relative to the speed of light. This condition typically holds for relatively small magnetic fields (about 100G). Analytical formulas are derived for the effective radial force acting on the beam ions, which can be used to minimize beam pinching. The results of analytic theory have been verified by comparison with the simulation results obtained from two particle-in-cell codes, which show good agreement

FORECASTING OF ELECTRICITY CONSUMPTION BY INDUSTRIAL ENTERPRISES BY THE METHOD OF EXPONENTIAL SMOOTHING

The paper describes the application of the method of exponential smoothing for forecasting electrical energy consumption of an industrial enterprise. The forecast is built using the software package STATISTICA to accelerate the calculation procedure. The results of forecasting the estimation of the quality of a 'forecast model.В работе описывается применение метода экспоненциального сглаживания для прогнозирования электропотребления промышленного предприятия. Прогноз построен с помощью программного пакета STATISTICA для ускорения процедуры расчета. По результатам построения прогноза выполнена оценка качества прогнозной модели

Discrete analogues of the Liouville equation

The notion of Laplace invariants is transferred to the lattices and discrete equations which are difference analogs of hyperbolic PDE's with two independent variables. The sequence of Laplace invariants satisfy the discrete analog of twodimensional Toda lattice. The terminating of this sequence by zeroes is proved to be the necessary condition for existence of the integrals of the equation under consideration. The formulae are presented for the higher symmetries of the equations possessing integrals. The general theory is illustrated by examples of difference analogs of Liouville equation.Comment: LaTeX, 15 pages, submitted to Teor. i Mat. Fi

Proton polarizability and the Lamb shift in muonic hydrogen

The proton structure and proton polarizability corrections to the Lamb shift of electronic hydrogen and muonic hydrogen were evaluated on the basis of modern experimental data on deep inelastic structure functions. Numerical value of proton polarizability contribution to (2P-2S) Lamb shift is equal to 4.4 GHz.Comment: 8 pages, LaTeX2.09, 2 figures, uses linedraw.st

Satellite traceology: experience of using in the interests of mammalogy for protection of ice-associated marine mammals

Advanced technology of satellite traceology is presented on the base of using the synthetic aperture radar (SAR) with high space and deep resolution installed for the first time onboard Soviet space station Almaz and now functioning successfully onboard the satellites Envisat and RADARSAT. The SAR traceology is the central issue of the satellite eco-criminology and concerns to theory of the traces formation, variability, and preservation in undamaged state. Ships coordinates, their traces and complexity of ice routing are fixed by the method of satellite charting, and their possible influence on ice-associated marine mammals is assessed. Numerous examples of SAR satellite control on navigation in stormy weather and ships’ presence in ice with different compactness, origin and age are overviewed, as well as impact of travel facilities on ice-associated animals welfare. Some incidents potentially dangerous for marine mammals are considered for the Gulf of Finland (Baltic Sea). Parameters of the ice cover, as openings, large fractures, and polynyas made by icebreakers in this area were determined on the base of the satellite SAR data, comprehensive digital ice maps with scheme of real ships’ routes in the ice were prepared, and the routes correspondence with ESIMO demands was assessed. The satellite SAR survey in the Kandalaksha Bay (White Sea) allowed to fix that winter navigation in the White Sea provoked formation of fractures and polynyas and reduced the sea ice area suitable for reproduction of greenland seals. For validation of this situation, airborne control was organized aboard the aircraft L-410 «Nord» that provided panoramic and IR images of ship channel through the rookeries of the seals in time of their reproduction. Besides, the aircraft made observations of pacific walruses behavior in the Bering Sea which were superposed with the satellite SAR and passive microwave survey in frame of the project «Pacific Walrus». Traceological control of the sea ice in the Anadyr Bay (Bering Sea) allowed to determine the size of openings in the ice and to assess the influence of tide and wind on welfare of ice-associated marine mammals. Some cases of infringement the regulation of navigation were revealed by means of the satellite SAR traceology

Proton polarizability effect in the Lamb shift of the hydrogen atom

The proton polarizability correction to the Lamb shift of electronic and muonic hydrogen is calculated on the basis of isobar model and experimental data on the structure functions of deep inelastic lepton-nucleon scattering. The contributions of the Born terms, vector-meson exchanges and nucleon resonances are taken into account in the construction of the photoabsorption cross sections for transversely and longitudinally polarized virtual photons sigma_{T,L}.Comment: 11 pages, 3 figure