A Study of the Luminescence of the Lyman–Birge–Hopfield Bands in the Atmospheres of the Earth and Titan

Cosmic Research - Calculations were made of the volume and integral emission intensities of the Lyman–Birge–Hopfield (LBH) bands of molecular nitrogen at 146.4, 138.4, 135.4, and 132.5...     

Observations of the Subauroral Nonthermal Radio Emission of the Earth in 1995–1998

Results of almost four years of continuous observations of the subauroral nonthermal radio emission (SANE) onboard the Interball-1 satellite are presented. The main features of SANE are described and discussed: the intensity and character of a signal, its appearance in time, beam directivity, propagation distance, and other observed parameters.     

Variations in the Parameters of Radio Waves in the Earth’s High-Latitude Ionosphere on the Satellite–Satellite Paths during the Geomagnetic Storm of June 22–23, 2015

Cosmic Research - This paper analyzes the results of about 100 radio occultation sessions of sounding of the high-latitude (>65 °N) lower ionosphere of the Earth’s Northern...     

Dynamics of the Radiation Environment in the Near-Earth Space in September–November 2020 according to the Meteor-M and Electro-L Satellite Data

Cosmic Research - The results of a comparative analysis from Russian satellite data on the radiation environment in the near-Earth space during September–November 2020 are presented. The...     

Design of transfer trajectories between resonant orbits in the Earth–Moon restricted problem

The application of dynamical systems techniques to mission design has demonstrated that employing invariant manifolds and resonant flybys enables previously unknown trajectory options and potentially reduces the ΔV$\mathrm{\Delta }V$ requirements. In this investigation, planar and three-dimensional resonant orbits are analyzed and cataloged in the Earth–Moon system and the associated invariant manifold structures are computed and visualized with the aid of higher-dimensional Poincaré maps. The relationship between the manifold trajectories associated with multiple resonant orbits is explored through the maps with the objective of constructing resonant transfer arcs. As a result, planar and three-dimensional homoclinic- and heteroclinic-type trajectories between unstable periodic resonant orbits are identified in the Earth–Moon system. To further illustrate the applicability of 2D and 3D resonant orbits in preliminary trajectory design, planar transfers to the vicinity of L₅ and an out-of-plane transfer to a 3D periodic orbit, one that tours the entire Earth–Moon system, are constructed. The design process exploits the invariant manifolds associated with orbits in resonance with the Moon as transfer mechanisms.     

Variations in rigidity spectrum and anisotropy of cosmic rays during sporadic phenomena in the heliosphere in October–November 2003

The variations in the cosmic ray (CR) anisotropy have been studied by the method of spectrographic global survey in the period from October 1 to November 30, 2003. The data of ground-based observations of CR intensity measured by the world network of stations were used. It is shown that at some instants of the period under investigation a bidirectional anisotropy of large amplitude (tens of percent) is observed in the angular distribution of particles. This indicates, first, a carryover of looplike structures of the interplanetary magnetic field (IMF) by coronal mass ejections and, second, a high degree of regularity of the IMF in these structures. The maximum amplitude of the bidirectional anisotropy (for particles with a rigidity of 4 GV) was observed on October 29 and 31 (50% and 30%, respectively) and on November 21–24 (15%). Using the data of ground-based and satellite measurements of the CR intensity in the period under study, we have investigated variations of the rigidity spectrum of protons in the energy range from 15 MeV to tens of GeV. The analysis was carried out in the context of the model of CR modulation by regular electromagnetic fields of the heliosphere. Parameters of the model rigidity spectrum of CRs are determined for every hour of observation. Using their values we have estimated the characteristics of electromagnetic fields of the solar corona and heliosphere that were responsible for powerful sporadic phenomena from the end of October to the beginning of November and after November 20, 2003.Translated from Kosmicheskie Issledovaniya, Vol. 42, No. 6, 2004, pp. 645–652.Original Russian Text Copyright © 2004 by Dvornikov, Sdobnov, Yudina.     

Radial gradient of low-energy (∼0.5–2 MeV) protons at 20–80 AU in the solar activity minima of the 22nd and 23rd cycles

The value of the radial gradient of low-energy (0.5–2 MeV) protons in the heliosphere at distances of 20–80 AU in the periods of solar activity minima in 1985–1987 and 1994–1997 was estimated using the data of the Voyager-1 and Voyager-2 spacecraft (s/c). Preliminary results on the dependence of the radial gradient on the distance were obtained for protons of these energies. The value of the radial gradient varies from –3% (AU)^–1 to –1% (AU)^–1 at distances from the Sun of 20–60 AU, reaching +0.7% (AU)^–1 at maximum considered distances (80 AU). The sign reversal of the proton radial gradient at a distance of 60–70 AU is interpreted as the appearance of a new component: up to the point of inversion there are mainly particles of the solar origin and/or accelerated in the inner heliosphere, while after the reversal of the gradients sign the fluxes of particles prevail whose source is located far from the Sun (maybe in the vicinity of the heliosphere boundary in the region of existence of the termination shock).Translated from Kosmicheskie Issledovaniya, Vol. 43, No. 1, 2005, pp. 3–8.Original Russian Text Copyright © 2005 by Logachev, Zeldovich, Surova.     

Diurnal and longitudinal variations in the earth’s ionosphere in the period of solstice in conditions of a deep minimum of solar activity

The results of studies of longitudinal and LT variations in parameters of the ionosphere–plasmasphere system, obtained using the Global Self-Consistent Model of the Thermosphere, Ionosphere and Protonosphere (GSM TIP), assimilation ionospheric model IRI Real-Time Assimilation Mapping (IRTAM), and satellite and ground-based observational data are presented in the paper. The study of the main morphological features of longitudinal and LT variations in the critical frequency of the ionospheric F2 layer (foF2) and total electron content (TEC) depending on latitude in the winter solstice during a solar-activity minimum (December 22, 2009) is carried out. It is shown that the variations in foF2 and TEC, on the whole, are identical, and so mutually substitutable, while creating empirical models of these parameters in quiet geomagnetic conditions. The longitudinal and LT variations in both foF2 and TEC are within an order of magnitude everywhere except for the equator anomaly region, where LT variation is larger by an order of magnitude than longitudinal variation. According to the results of the study, in the American longitudinal sector at all latitudes of the Southern (summer) Hemisphere, maxima of foF2 and TEC are formed. The near-equatorial and high-latitudinal maxima are separated out from these. The estimate of the contribution into the longitudinal variation in foF2 and TEC for various local time sectors and at various latitudes has been obtained for the first time. In the Southern (summer) Hemisphere, longitudinal variation in foF2 and TEC is formed in the nighttime.     

Frequency fluctuations of coherent signals from spacecraft observed during dual-frequency radio sounding of the circumsolar plasma in 2004–2008

We have performed spectral processing of the data of experiments on radio sounding of circumsolar plasma by coherent S- and X-band signals from the spacecraft Ulysses, Mars Express, Rosetta, and Venus Express carried out from 1991 to 2009. The experiments were realized in the mode of coherent response, when a signal stabilized by the hydrogen standard is transmitted from the ground station to a spacecraft, received by the onboard systems, and retransmitted to the Earth with conserved coherence. Thus, the signal sounding the coronal plasma passes twice through the medium: on the propagation path ground station — spacecraft and on the same path in the opposite direction. The spectra of frequency fluctuations in both the bands are obtained and, using them, the radial dependences of fluctuation intensities are found, which can be approximated by a power law. It is shown that the ratio of intensities of frequency fluctuations in the S- and X-bands is comparable with the theoretical value and characterizes the degree of correlation of irregularities of the electron density along the propagation path ground station — spacecraft and back. Analysis of the correlation of frequency fluctuations on the two paths allows one to get a lower estimate of the outer scale of the circumsolar plasma turbulence. For heliocentric distances R = 10 solar radii (R _S ) the outer scale is larger than 0.25R _S .     

Peculiarities of the formation of a thin current sheet in the Earth’s magnetosphere

We investigate the process of the self-consistent formation of a thin current sheet with a thickness close to the ion Larmor gyroradius in the presence of decreasing magnetic field’s normal component B_n. This behavior is typical of the current sheet of the Earth’s magnetospheric tail during geomagnetic substorms. It has been shown that, in a numerical model of the current sheet, based on the particle-in-cell method, the appearance of self-consistent electric field component E_y in the current sheet vicinity can lead to its significant thinning and, eventually, to the formation of a multiscale configuration with a thin current sheet (TCS) in the central region supported by transient particles. The structure of the resulting equilibrium is determined by the initial parameters of the model and by the particle dynamics during the sheet thinning. Under certain conditions, the particle drift in the crossed electric and magnetic fields leads to a significant portion of ions becoming trapped near the neutral sheet and, in this way, to the formation of a wider configuration with an embedded thin current sheet. The population of trapped particles produces diamagnetic negative currents that manifest in the form of negative wings at the periphery of the sheet. Correspondingly, in the direction perpendicular to the sheet, a nonmonotonic coordinate dependence of the magnetic field appears. The mechanisms of the evolution of the current sheet in the Earth’s magnetotail and the formation of a multiscale structure are discussed.     

Features of the Motion of the Earth’s Geographic North Pole and Jumping in the Geomagnetic Field

Cosmic Research - The results of an analysis and comparison of times of appearance of the features of the long-term displacement of the geographic North Pole over the Earth’s surface and the...     

Influence of simulated high-G on the weld size of aL–lI alloy

Whether welding processes are used on earth or in space, they have the same objective: to obtain defect-free welds. To fully understand the effect of gravity on the weld pool geometry and solidification one should perform experiments within a broad range of gravitational acceleration. High-gravity arc welding experiments were done on Al–Li alloy using the centrifuge called Multi-Gravity Research Welding System (MGRWS). At a high “g” level, buoyancy-driven flow is the dominant force in the weld pool over the Marangoni and the electromagnetic forces. Preliminary results show that the average grain size in the fusion zone at 1g is smaller that at 5g.     

Development Trend of Application Satellites in China at the Beginning of the 21st Century

ＤｅｖｅｌｏｐｍｅｎｔＴｒｅｎｄｏｆＡｐｐｌｉｃａｔｉｏｎＳａｔｅｌｉｔｅｓｉｎＣｈｉｎａａｔｔｈｅＢｅｇｉｎｎｉｎｇｏｆｔｈｅ２１ｓｔＣｅｎｔｕｒｙＢｙＭａＸｉｎｇｒｕｉａｎｄＷａｎｇＪｉｎｇｑｕａｎＴｈｅＥａｒｔｈＲｅｓｏｕｒｃｅｓＳａｔｅｌｉｔ...     

Global impulse burst of geomagnetic pulsations in the frequency range of 0.2–5 Hz as a precursor of the sudden commencement of St. Patrick’s Day 2015 geomagnetic storm

We have analyzed a short-term (3–4 s) burst of geomagnetic pulsations in the frequency range of 0.2–5 Hz observed during the commencement of a magnetic storm on March 17, 2015. The burst was observed by a network of observatories in different sectors of local time and at different latitudes. The spectra of pulsations involves a resonant structure with a global maximum at a frequency of 2.78 ± 0.38 Hz, despite some differences at different observatories. There is a delay by almost 4 s in the maximum of the train amplitude at nightside observatories with respect to a dayside observatory. The burst of pulsations has been shown to be on the front of the magnetic disturbance associated with sudden storm commencement (SSC) and, therefore, can be considered as a precursor. The observations of particle fluxes by low-orbit satellites have shown that the SSC is accompanied by a dramatic increase in the fluxes of precipitating protons and electrons. We have suggested that the mechanism of oscillation generation may be the ion–cyclotron instability of ring current protons and the resonant structure of pulsations may be associated with the ionospheric Alfvén resonator.     

Time Variations of Low-Energy Protons and Helium Nuclei (0.3–10 MeV/nucleon) during the Quiescent Time of Solar Activity in the Inner Heliosphere

Time variations with a duration of 0.6–1.5 years are studied in the interplanetary space for protons and helium nuclei with energies of 0.3–10 MeV per nucleon at a quiescent time of solar activity. It is shown that at 1 AU in the periods 1978–1981 and 1988–1990, at the phases of growth of the 21st and 22nd solar cycles, the background fluxes of these particles determined as minimum intensity levels in every month increased demonstrating steplike variations. At the same time, the intensity of galactic cosmic rays (GCRs) decreased also with the formation of modulation steps. Each step of low-energy particles was finished by a deep minimum of intensity (gap) in both protons and helium nuclei and with a simultaneous short-term increase of the GCR intensity. We present the results of studying five such steps in the intensity of low-energy particles that were observed simultaneously and were opposite in phase with modulation steps of galactic particles. The lowest values of the H/He ratio were recorded at the end of every step, at the lowest intensities of these particles, i.e., in the gap. The true background population at 1 AU was detected precisely at these time intervals, when the contributions of flare particles and those accelerated in the international space were minimum. Various possibilities of the origination of the steplike variations of the background fluxes of protons and helium nuclei with energies of 0.3–10 MeV per nucleon, correlated with similar GCR variations, are discussed.     

Variations of the magnetopause position versus the level of geomagnetic activity (according to data of the INTERBALL-1 Satellite for 1995–1997)

The variations in the deviation of the observed position of the magnetosphere boundary from its mean position predicted by the Shue at al., 1997 (Sh97) model [7] are studied as a function of the substorm activity level (the AE-index value) and magnetic storm intensity (the value of the corrected D _st ^* index). The results obtained make it possible to state that the amplitude of motion of the magnetospheric boundary on the dayside and in the low-latitude tail is small. It is likely that the position of the boundary is either independent of the AE and D _st ^* indices or this dependence is weak. At the same time, the boundary of the high-latitude tail shifts inward on the average by 1.5R _E with an increase of the AE-index in the case of absence of magnetic storms (contraction of the magnetospheric tail). On the contrary, in the presence of magnetic storms, this boundary shifts outward by up to 3R _E with an increase of the AE-index (inflation of the magnetospheric tail). It is also shown that the boundary of the high-latitude tail moves outward with an increase of the D _st ^* index, both at low substorm activity and in periods of high substorm activity. The amplitude of the outward motion of the high-latitude tail of the magnetosphere is by a factor of two higher for moderate magnetic storms with strong substorms than for moderate magnetic storms with weak substorms.     

On the strategy of space station injection in the point of Earth — Moon Libration / way of making the asteroid patrol/

One of the most important problem in the ecological area that stay for humanity is the problem of prevention Earth and asteroids collision. The danger of such collision isn't realized of the general public. But we know that on average twice in the every century the Earth comes into collision with the large celestial bodies (for example Tungussky or Arizonsky meteorites). The incidence of such meteorite in density population region of the Earth will simulate the ecumenical catastrophe. Much more seldom the Earth experiences collision with the particularly large celestial bodies. In accordance with one of the hypotheses namely the collision Earth with such body 65,000,000 years ago leads to the global change of Earth biosphere (in particular to the extinction of dinosaurs).Now we are able to stave off or at least to forewarn of this danger. One of the way for that is making the specific space station - asteroid patrol. Such the station will be able to track the approaching celestial bodies and perhaps (on second stage) to attempt altering its trajectory (for example with directional thermonuclear explosions)Some of the expedient points in the Space for the asteroid patrol's placing are the librations' points of the Earth - Moon system. In the report the preliminary results of analysis the problem of space station's taking into the libration's point are presented. For this taking it is suggested the electric jet propulsion to use.     

The Description of the Open Model in College English Teaching

In order to solve the current problems in the college English teaching and meet the demands of the ＂College English Curriculum Requirements＂, the Open Model in College English teaching is proposed in the thesis. The thesis describes the model from the five components,