Model radiation spectrum for an accretion disk near a rotating black hole

ASCA, RXTE, and Chandra observations of Seyfert galaxies indicate the presence in their spectra of broad emission lines with characteristic double-peaked pro files, which could arise in the inner regions of an accretion disk. In such regions, general relativistic effects must be taken into account, and may even dominate. In connection with this, we have constructed the radiation spectrum for an individual spectral line for a model isothermal Kerr accretion disk. This demonstrates the manifestation of general relativistic effects in pure form, unclouded by effects associated with models for the structure of the disk itself. It is assumed that matter in the disk moves in circular geodesics in the equatorial plane. The spectrum retains a characteristic two-peaked profile for wide ranges of values of the radial coordinate of the radiating region, angular momentum of the black hole, and viewing angle. The inner regions of the disk make an appreciable contribution to the red wing of the spectrum.     

First results from the plasma composition spectrometer PROMICS-3 in the Interball project

PROMICS-3 is a plasma experiment flown in the Russian project Interball. It performs three-dimensional (3D) measurements of ions in the energy range 4 eV–70 keV with mass separation and of electrons in the energy range 12 eV–35 keV. The Interball project consists of two main satellites, the Tail Probe and the Auroral Probe, each with one subsatellite. The Interball Tail Probe was launched on 3 August 1995, into a 65° inclination orbit with apogee at about 30 R_E. Both main satellites carry identical PROMICS-3 instruments and thus direct comparisons of the particle distributions will be possible once the Auroral Probe is launched. Furthermore, PROMICS-3-Tail is the first instrument measuring the 3D ion distribution function in the magnetospheric boundary layers at high latitudes. In this paper we describe the PROMICS-3 instrument and show initial results from the Tail probe, measurements of the mag-netosheath, plasma sheet, and ring current plasmas.     

The Relationship between the Taimyr Collision and Trap Magmatism Based on Geological Data and Modeling Results

Collision and trap magmatism are spatially conjugated within the Taimyr fold region. Trap magmatism is related in time to late collision and postcollision stages. Supercomputer modeling makes it to possible to reveal the potential for mantle and crust heating at the late collision stages, accompanied by largescale basaltic magmatism.     

First results from the hot plasma instrument PROMICS-3 on Interball-2

The PROMICS-3 instrument on Interball-2 is nominally identical to the PROMICS-3 instrument on Interball-1. It performs three-dimensional measurements of ions in the energy range 4 eV–70 keV with mass separation and of electrons in the energy range 300 eV–35 keV. Interball-2 was launched on August 29, 1996, into an orbit with the same inclination as that of Interball-1, 63°, but with apogee at 20 000 km. In this study the PROMICS-3 instrument on Interball-2 is briefly described and examples of the first results are presented. Firstly, we report observations of upward moving molecular ions with energies of up to 700 eV at the poleward edge of the auroral oval. Previous observations of outflowing molecular ions have been at lower altitudes and lower energies. Secondly, we show observations of dawnside magnetosheath plasma injections. Using conjugate data from both PROMICS-3 instruments we have found dispersion structures above the morningside auroral oval, which occurred simultaneously with isolated “pockets” of magnetosheath plasma at a distance of X_GSM = −14 to −12 R_E, which had been injected into the inner part of the low-latitude boundary layer. These isolated plasma structures were sites of strong field-aligned currents and are proposed to be the magnetospheric counterparts of the dispersion structures.     

Project of the mission to Phobos

This article provides the main scientific objectives and characteristics of the Phobos-Soil project, intended to fly to the Martian satellite Phobos, deliver its soil samples to the Earth, as well as explore Phobos, Mars, and the Martian environment with onboard scientific instruments. We give the basic parameters of the ballistic scenario of the mission, spacecraft, and some scientific problems to be solved with the help of the scientific instruments installed on the spacecraft.     

Samarium-monosulfide-based semiconductor strain gages for spacecraft-strain transformation

The theoretical basis of the measured strain transform by strain gages made of samarium monosulfide and other semiconductors in increments of electrical resistance is considered. Specific structures of semiconductor strain gages based on samarium monosulfide are presented.     

CLASSIFICATION OF FOREST TYPES FROM TEXTURAL CHARACTERISTICS OF SIR-C RADAR IMAGES

Methods for classifying land-cover types on the basis of image texture through processing of synthetic-aperture radar (SAR) imagery are described. A combination of statistical characteristics, as well as matrices of conversion probabilities for amplitudes of readings of SAR images, are used in the analysis of texture values. The results of the processing of SIR-C SAR images recorded from aboard the Shuttle spacecraft using these methods are presented for the purpose of classification of forest types.     

Models of seismotectonic systems with dry friction

Several models of a seismic regime and block dynamics that are based on frictional self-oscillations in systems with nonlinear dry friction are considered. The set of Burridge-Knopoff models is presented to describe the generation of earthquakes with the relative movement of the fault sides. The disk model, which describes rotary dynamics of the crustal blocks, and the model of the block dynamics in the foredeeps, are examined. It is established that a regime of chaotic oscillations exists in a certain range of parameters (frictional force, the velocity of leading blocks, etc.) in the considered systems. This limits the predictability of these systems.