126 research outputs found
Ionized gas and sources of its ionization in the Irr galaxy IC 10
IC 10 is the nearest starburst irregular galaxy remarkable for its
anomalously high number of WR stars. We report the results of an analysis of
the emission spectra of HII-regions ionized by star clusters and WR stars based
on observations made with the 6-m telescope of the Special Astrophysical
Observatory of the Russian Academy of Sciences using MPFS field spectrograph
and SCORPIO focal reducer operating in the slit spectrograph mode. We determine
the masses and ages of ionizing star clusters in the violent star-forming
region of the galaxy in terms of the new evolutionary models of emission-line
spectra of HII-regions developed by Martin-Manjon et al. (2010). We estimate
the amount of stars needed to ionize the gas in the brightest HII-region HL 111
and report new determinations of oxygen abundance in HII regions.Comment: To appear in the proceedings of the conference "A Universe of dwarf
galaxies" (Lyon, June 14-18, 2010
Matrix WKB solution for electromagnetic waves in an inhomogeneous gyrotropic medium
A matrix solution 4x4 was obtained within the framework of the Wentzel–Kramers–Brillouin method for inclined incidence on a plane electromagnetic wave on an inhomogeneous gyrotropic layer in an external magnetic field with a direction changing in space. Using the obtained matrix solution, the absolute values of the reflectance matrix coefficients and the energy reflection coefficients for the s and p polarized waves are calculated. The dependence of the off-diagonal coefficients of the reflection matrix on the angle of the total rotation of the external magnetic field strength vector within the layer is shown
The propagation of pulses of a special shape in an inhomogeneous anisotropic medium with dispersion and torsion of the optical axis
An oblique incidence of polarized light pulses with different envelope shapes is considered: triangular, Gaussian, rectangular and in the form of giant laser pulses onto a flat inhomogeneous anisotropic layer with torsion of the optical axis and optical dispersion. The wavelength of an optical pulse carrier is close to the resonance wavelength of an inhomogeneous anisotropic layer. The problem of the propagation of s- and p-polarization waves through a layer, the reflection of impulses of cross-polarized components, the dependence of modulation coefficients during medium torsion and frequency detuning is considered
Peculiarities of the bunch shape monitor operation for high-intensity electron beams
The simulation results of the Bunch Shape Monitor operation using coherent transformation of a time structure of an analyzed high-intensity electron beam into a spatial one of low-energy electrons emitted from a wire target will be presented. The electromagnetic field of an analyzed bunch disturbs the trajectories of secondary electrons, thus resulting in a degradation of phase resolution and in errors of phase position reading. Moreover there is a perturbation of the target potential due to the current compensating emission of the secondary electrons. The accuracy analysis has been carried out. The confident result to achieve the phase resolution less then one degree was obtained
Giant Cyclones in Gaseous Discs of Spiral Galaxies
We report detection of giant cyclonic vortices in the gaseous disc of the
spiral galaxy NGC 3631 in the reference frame rotating with the spiral pattern.
A presence of such structures was predicted by the authors for galaxies, where
the radial gradient of the perturbed velocity exceeds that of the rotational
velocity. This situation really takes place in NGC 3631.Comment: 13 pages, 4 EPS and 3 PS figure
The WKB 4x4 method for an inhomogeneous chiral layer
The propagation of a plane electromagnetic wave in a plane inhomogeneous chiral
medium with oblique incidence is considered. A solution of the ordinary differential equations
system 4x4 was obtained by the Wentzel–Kramers–Brillouin method in the form of a Cauchy
matrix. The dependence of the cross-polarized components on the reflection from the profile of
the chirality parameter and the angle of incidence is shown
Global Models, The Biospheric Approach (Theory of the Noosphere)
The problem of the coevolution of mankind and the biosphere, i.e., the relationship between the process of the evolution of the biosphere and the evolution of human activity which provides a homeostasis for human civilization, has become one of the principal problems of human ecology.
The first step in an extensive program of interdisciplinary research is the creation of a system of mathematical models which would serve as a framework for planning international research programs.
The research described herein has two stages. The first stage, a still primitive system of models was constructed and analyzed, using systems dynamics techniques. This system of models, outlined in the second section of the paper, has already helped the authors in their contacts with experts in biology, soil science, etc., and the creation of an information base has in essence, turned into a discussion of plans for future work. Studies connected with simulating the evolution of the biosphere were developed in three directions: simulation of processes of a biotic nature, simulation of climate, and simulation of human activity.
Experimental results obtained using this system in the "if...then" mode, may be helpful for understanding, at least on a qualitative basis, possible impacts of human activity on the evolution of the biosphere assuming that the present day trends remain unchanged. This system of models is at present programmed at IIASA and is ready to be used for simulation experiments.
The second step in the research is based on an understanding of the fact that the systems dynamic approach is not sufficient for the elaboration and study of the system of models which describes human activity. Furthermore, it is necessary to analyze and coordinate models developed by experts in varied branches of science -- biologists, climatologists, economists, etc. Thus, it is necessary to elaborate new mathematical techniques that can be used in the investigation of global coevolution problems. Some principles for the development of these techniques were formulated at the Computing Center of the USSR Academy of Sciences and are presented herein. The three main principles are:
(1) Linear parametrization of comprehensive submodels;
(2) Models of human activity are split into two levels -- the decision-making level and the technological level -- and a description of the system of models at the technological level only;
(3) Analysis and coordination of the system of models by constructing a set of all reachable values of performance indices (The Generalized Reachable Sets Approach).
The linear parametrization procedure for a climate model which is essentially the Mintz-Arakawa global atmospheric circulation model as described by Gates et al. (1971) and modified to account for the climatic trends due to the influence of anthropogenic factors, is described in the third section of the paper.
The problems of modeling human activity and the main features of the Generalized Reachable Sets approach, as well as the general scheme of analysis of global biospheric models, are presented in the fourth section of the paper.
This work, which is now in the early stages, calls for a great deal of scientific effort over a long period of time. The authors anticipate that the importance of the research in this direction will be internationally recognized and supported
Levy Anomalous Diffusion and Fractional Fokker--Planck Equation
We demonstrate that the Fokker-Planck equation can be generalized into a
'Fractional Fokker-Planck' equation, i.e. an equation which includes fractional
space differentiations, in order to encompass the wide class of anomalous
diffusions due to a Levy stable stochastic forcing. A precise determination of
this equation is obtained by substituting a Levy stable source to the classical
gaussian one in the Langevin equation. This yields not only the anomalous
diffusion coefficient, but a non trivial fractional operator which corresponds
to the possible asymmetry of the Levy stable source. Both of them cannot be
obtained by scaling arguments. The (mono-) scaling behaviors of the Fractional
Fokker-Planck equation and of its solutions are analysed and a generalization
of the Einstein relation for the anomalous diffusion coefficient is obtained.
This generalization yields a straightforward physical interpretation of the
parameters of Levy stable distributions. Furthermore, with the help of
important examples, we show the applicability of the Fractional Fokker-Planck
equation in physics.Comment: 22 pages; To Appear in Physica
An interactive procedure of a transverse beam matching and correction in INR Linac
An application package is developed to carry out an interactive procedure for a transverse beam matching and
correction in INR Linac. The results of multiple beam profile measurements in several accelerator areas are used.
The currents in steering coils are found to suppress the beam displacement. The gradients in quadrupole lenses are
calculated to match the beam. This procedure is successfully used in accelerator tuning.Разработан пакет программ для проведения интерактивной процедуры поперечного согласования и коррекции пучка по результатам измерения профилей пучка на различных участках линейного ускорителя ИЯИ РАН. Определяются режимы включения корректирующих элементов для выведения пучка на ось ускорителя и градиенты полей квадрупольных линз для согласования пучка с фокусирующим каналом ускорителя. Разработанная процедура успешно используется при настройке режимов работы ускорителя.Розроблено пакет програм для проведення інтерактивної процедури поперечного узгодження і корекції
пучка за результатами виміру профілів пучка на різних ділянках лінійного прискорювача ІЯД РАН.
Визначаються режими включення коригувальних елементів для виведення пучка на вісь прискорювача і
градієнти полів квадрупольних лінз для узгодження пучка з фокусуючим каналом прискорювача.
Розроблена процедура успішно використається при настроюванні режимів роботи прискорювача
Analyzing solar, cosmic, and geophysical events in September 2017 using SHIСRA SB RAS complex observations
We report the results of monitoring of cosmic rays and geomagnetic field along 210 magnetic meridians in Yakutia in the first half of September 2017. The energy spectrum of solar cosmic rays during Ground Level Enhancement in September 10, 2017 is estimated as J=3027E–1.99exp(–E/729 MeV). We present the results of the forecast and complex analysis of the magnetic storm on September 7–9, 2017 with Dst=–124 nT. The forecast lead time is about one day. We examine how the storm affected the electric potential and VLF signal propagation from RSDN-20 radio navigation stations. Irregular Pi3–Pi1 pulsations occurred during the September 8, 2017 magnetic storm from 12 to 20 UT. The pulsations were accompanied by variations in electrotelluric potentials and geomagnetic fields with the correlation coefficient between them ρ(E, H)=0.5÷0.9. The effects of the magnetic storm manifested themselves as an increase in the attenuation and a decrease in the phase delay of VLF radio signals
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