INTERBALL-1 Observations of the Kilometric “Continuum” of the Earth's Magnetosphere

The electromagnetic radio-frequency emission of the inner region of the Earth's plasmasphere discovered recently by the GEOTAIL satellite [4] and referred to as the kilometric continuum was observed by the INTERBALL-1 satellite (1995–2000) in the 100–500 kHz band in the AKR-X experiment. During a period of low solar activity (1995–1997), this continuum was found leaving the inner plasmasphere at geocentric distances of 2–4R _E as isolated pencil-like (1°–6°) beams located in the magnetic equator plane. During a time of high solar activity (1999–2000), the occurrence of the emission was extremely rare (it was observed only at a considerable fall of this activity). If detected, at the same geocentric distances (2–4R _E) the continuum demonstrated a strongly variable and perturbed character, as well as a considerably larger extension of the beam over the geomagnetic latitude (10°–20° and more). In addition, quasi-periodic (QP) signals, similar to the observed QP emissions of Jupiter, were sometimes detected in this period. The probable nature of the observed features of the kilometric continuum is briefly discussed.     

Statistical Approach to the Evaluation of the Mean Correlation Length and the Propagation Velocity of Middle-Scale Plasma Structures in the Earth's Foreshock

Based on simultaneous measurements of ion fluxes made onboard the closely separated satellites Interball-1and Magion-4, the propagation velocity of middle-scale plasma structures in the Earth's foreshock relative to the solar wind flow is estimated. The derived value of this velocity allows these structures to be identified as a fast magnetosonic wave propagating upstream of the solar wind inflowing the Earth's bow shock. An evaluation is also made of the correlation length of these disturbances in the plane perpendicular to the Sun–Earth line. This length is approximately equal to 2R _E.     

Verification of the Accuracy of the Magnetopause Empirical Models Using the INTERBALL-1 Satellite Data

A statistical analysis of the shape and location of the magnetopause according to the INTERBALL-1 satellite data for the period 1995–1997 is carried out. The instants of crossing the magnetosphere boundaries obtained by the plasma and magnetic data are compared with computations based on three empirical models, namely, Petrinec and Russel, 1996; Shue et al., 1997; and Shue et al., 1998. The state of the interplanetary medium (dynamic pressure of the solar wind plasma P _d and the B _z component of the interplanetary magnetic field) was determined by the measurements onboard the WIND spacecraft. We estimate the accuracy of the considered models for different groups of boundary crossings: single, multiple with small duration (less than 40 min), and multiple with large duration (more than 40 min). It is demonstrated that the small-scale motions of the boundary (<1R _E) are observed more often in the dayside magnetosphere, especially near the cusp region. Large-scale boundary oscillations (>1R _E) are more common in the tail region of the magnetosphere, namely, its flanks. Various models give similar results: about 50% of all events have deviations by more than 1R _E from the model locations. In some cases, the deviation of the measured location of the magnetosphere boundary from the model prediction may be as large as 5–6R _E for all three models considered, the actual boundary being more often located nearer to the Earth than the result of model computations. The best model is that of Shue et al., 1998, but it does not differ significantly from the other models.     

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.     

Manifestations of sudden commencement of a severe magnetic storm of November 20, 2003, in generation of an SC pulse, <Emphasis Type="Italic">P</Emphasis><Subscript>SC</Subscript> pulsations,and spatial modulation of the auroral brightness

The results of investigation of the geomagnetic and auroral response to the commencement of a severe magnetic storm of November 20, 2003, are presented. It is established that the onset of SC led to the brightening of the auroral arc in the dusk sector for 2–3 min with its extent to the east with a velocity of 10–20 km/s and to displacement poleward with a velocity of 1.0 km/s. Furtheron, the fast auroral expansions of short duration (5 min) to the pole up to 2–4°were observed, repeating every 5–10 min during 40 min, which led to the spatial modulation of the brightness of the glow and to generation of P_SC pulsations with similar periods of oscillations. The broadening of aurora poleward had a steplike character, with generation of new arcs poleward of previous ones 5 arcs per 1.5 min. The modulation of brightness of the glow and P_SC were observed against the background of intensification of a two-cell DP2 type current system and were accompanied by multiple turnings of the IMF B_z from south to north and back. It is assumed that the source of P_SC pulsations was a modulation of the intensity of the DP2 ionosphere currents as a result of variations of the magnetosphere convection level.Translated from Kosmicheskie Issledovaniya, Vol. 42, No. 6, 2004, pp. 608–615.Original Russian Text Copyright © 2004 by Baishev, Borisov, Velichko, Solovyev, Yumoto.     

Geosynchronous magnetopause crossings on October 29–31, 2003

During the period October 29–31, 2003, geosynchronous magnetopause crossings (GMC) have been identified based on the magnetic data of the GOES series spacecraft and plasma data of the LANL series spacecraft. It is shown that most of the time the size of the dayside magnetosphere was highly decreased under the effect of very high pressure associated with high velocities and densities of the solar wind plasma, as well as high negative values of the B_z component of the interplanetary magnetic field (IMF). For tens of hours the subsolar magnetopause was deep inside the geosynchronous orbit. During the main phase and at the maximum of the strong geomagnetic storms that occurred in the period under consideration, the dayside magnetosphere was characterized by a strong dawn-dusk asymmetry, so that its size in the postnoon sector considerably exceeded the size in the pre-noon sector. The geomagnetic disturbances in the morning on October 30 and 31, 2003 were accompanied by global magnetospheric pulsations with periods of 5–10 min and high amplitude (up to 0.8 R_E).Translated from Kosmicheskie Issledovaniya, Vol. 42, No. 6, 2004, pp. 574–584.Original Russian Text Copyright © 2004 by Dmitriev, Suvorova.     

Observation of the Near Plasma Sheet,Ring Current,and Energetic Electrons from Radiation Belts at a Geosynchronous Orbit,March 11–25, 1992

The dynamics of near plasma sheet electrons and ions (E 0.1–12.4 keV), ring current protons (E _i 41–133 keV), and energetic electrons from the Earth's radiation belts (E _e 97–1010 keV) is considered using the data from the Gorizont-34and Gorizont-35geosynchronous satellites from March 11–25, 1992. Peculiarities of this period are a long (more than 4 days) interval of the northward interplanetary magnetic field (B _z> 0) and a high-speed stream of the solar wind with an enhanced particle density. The SC and compression of the magnetosphere to the geosynchronous orbit (GMC) preceded this interval. Under quiet and moderately disturbed geomagnetic conditions and under a prolonged northward interplanetary magnetic field, we observed a significant decrease of fluxes and softening of spectra of the electron component of plasma in the energy ranges of 0.1–12.4 keV and 97–1010 keV, and of the ion component of plasma at energies of 0.1–4 keV, while the intensity of 5–12.4 keV ion fluxes increases by about one order of magnitude. The peculiarities of distributions of energetic particle fluxes observed in the period under consideration can be associated with significant variations of the convection conditions and a decreased or fully suppressed injection of energetic electrons into the geosynchronous orbit region.     

Statistical Relationships between Solar, Interplanetary, and Geomagnetospheric Disturbances, 1976–2000

Within the framework of the Space Weather program, 25-year data sets for solar X-ray observations, measurements of plasma and magnetic field parameters in the solar wind, and D _st index variations are analyzed to reveal the factors that have had the greatest influence on the development of magnetospheric storms. The correlation between solar flares and magnetic storms practically does not exceed a level of correlation for random processes. In particular, no relation was found between the importance of solar flares and the minimum of the D _st index for storms that could be connected with considered flares by their time delay. The coronal mass ejections (CME; data on these phenomena cover a small part of the interval) result in storms with D _st < –60 nT only in half of the cases. The most geoeffective interplanetary phenomena are the magnetic clouds (MC), which many believe to be interplanetary manifestations of CMEs, and compressions in the region of interaction of slow and fast streams in the solar wind (the so-called Corotating Interaction Region, CIR). They correspond to about two-thirds of all observed magnetic storms. For storms with –100 < D _st < –60 nT, the frequencies of storms from MC and CIR being approximately equal. For strong storms with D _st < – 100 nT, the fraction of storms from MC is considerably higher. The problems of reliable prediction of geomagnetic disturbances from observations of the Sun and conditions in interplanetary space are discussed.     

An Empirical Model of the Radiation Belt of Helium Nuclei

Based on satellite data, we present the results of modeling the spatial and energy distributions of integral fluxes of He nuclei (α particles) with E > 1, 2, 4, and 7 MeV at L = 1.1–6.6 in a broad range of B/B ₀ (E is the kinetic energy of particles, L is the drift shell parameter, and B/B ₀ is the magnetic field ratio). Some ways of practically applying the model are considered. The results of calculation of α-particle fluxes for a circular orbit with a height of 300 km and an inclination of 50° are presented.__________Translated from Kosmicheskie Issledovaniya, Vol. 43, No. 4, 2005, pp. 243–247.Original Russian Text Copyright © 2005 by Getselev, Sosnovets, Kovtyukh, Dmitriev, Podzolko, Vlasova, Reizman.     

Gravitational Sensitivity of Solutions–Melts at the Crystallization of Two-Phase InSb–InBi Alloys under Space Conditions

Analyzing the results of space and ground-based experiments carried out in the Baikov Institute of Metallurgy and Materials Science to study the processes of the melting and crystallization of two-phase InSb–InBi alloys of an indium–antimony–bismuth (In–Sb– Bi) triple system, we have demonstrated the gravitational sensitivity of the InSb-based solution– melt. It manifests itself as a certain asymmetry of the boundary of the dissolution of the InSb ingot by the InSb–InBi melt and heterogeneity of the melt along this boundary depending on the magnitude and direction of the gravity force acceleration gin the range (1–10^–3–10^–5)g ₀, where g ₀is the acceleration of the gravity force on Earth. For the first time, it is established in the experiments under analysis that the homogeneity of melts of a complex composition with components of various densities can be reached only at magnitudes of quasistationary (residual) microaccelerations g< 10^–6 g ₀.     

Energy Spectrum of Galactic 10–100 MeV Protons in Quiet Sun Periods

The dynamics of the proton energy spectrum during the solar cycle is studied. The spectra were determined by 1–100 MeV particle fluxes measured by different instruments mounted aboard the Earth's IMP-8 satellite for more than one hundred quiet-time intervals in the period between 1974 and 1991. The galactic branch of the spectra (E _p > 10 MeV) constructed for every quiet interval was fitted by a power law function, J =CE . The theory predicts that in the 1–100 MeV energy range, where the adiabatic cooling of particles is dominant, = 1, while we have derived a double-peak distribution. The main maximum has the mean value = 1.35. The mean value of the second, much weaker maximum, is = 0.95. Within the main maximum, values are distributed in accordance with the Gaussian law with a standard deviation D/ = 0.12. The substantial difference of from unity requires the elaboration of a new model of modulation processes in the inner heliosphere. The values corresponding to the second maximum show that modulation processes correspond sometimes to theoretical conceptions. It is shown that correlates weakly with parameters A and describing the solar branch of the spectrum (J(E) = AE ^–). At the same time, a more significant correlation is observed between and the solar activity index, R _z, the counting rate of the Deep River neutron monitor, and the energy value in the minimum of the energy spectrum flux, E _min.     

Dynamics of the 0.3–100 MeV Proton Energy Spectra in the Inner Heliosphere in Quiet Periods of 1974–1991

Variations of the proton spectra in the 0.3–100 MeV energy range based on the data of various instruments installed onboard the IMP-8 satellite are studied for very quiet, quiet, and quasi-stable solar activity periods during the years 1974–1991. As many as 118 spectra were approximated by two power laws: the left-hand and galactic branches of the spectrum were fitted by the AE ^– function and a dependence of the CE type, respectively, the sum J(E) = AE ^– + CE providing the total spectrum. It is shown that the spectra vary within a solar cycle with a shift of the minimum energy (E _min) to higher energies with increasing solar activity. It follows from the relations between the spectrum parameters thus obtained that, in particular periods of time, an increase (decrease) of the particle flux in the low-energy branch of the spectrum and an intensification (depression) of the GCR particle flux modulation take place simultaneously. This is manifested in a shift of the spectrum parallel to the energy axis. The study of the spectra in the most quiet time during three successive solar minima have shown that low-energy (0.3–10 MeV) protons, as well as GCR, are subject to the 22-year variation in the solar magnetic cycle.     

“Space superiority”: Wernher von Braun's campaign for a nuclear-armed space station, 1946–1956

The literature on the history of spaceflight has depicted the early 1950s Collier’s articles mostly as a forerunner to the peaceful and scientific exploration of space. Yet the centerpiece of Wernher von Braun's plan was a manned space station that would serve as reconnaissance platform and orbiting battle station for achieving “space superiority” over the USSR. One its roles could be the launching of nuclear missiles. When challenged as to the station's defensibility, von Braun even posited pre-emptive atomic strikes from space as a response to the development of a hostile anti-satellite capability.     

Statistical Relationships between Solar, Interplanetary, and Geomagnetic Disturbances, 1976–2000: 2

In this paper we continue the analysis of the influence of solar and interplanetary events on magnetospheric storms that was started in [1]. Two data sets are additionally analyzed in the present study: solar flares of importance M5 and greater in 1976–2000 and halo CMEs observed by the SOHO spacecraft during the period of 1996–2000. It is demonstrated that the statistical characteristics of the new set of flares and of that analyzed before in [1] differ little, while the geoeffectiveness of the halo CMEs turned out to be much less than that of the previously published CMEs.     

The navigational experiments on microgravitational space platform “FOTON-M2”

This paper presents the review of results of the navigating experiments which have been carried out during flight of microgravitational space platform (MSP) Foton-M2 in May–June 2005. The brief characteristic of the created MIRAGE–M equipment consisting from magnitometric system and satellite radionavigation receiver is given. The measurements have allowed to restore unguided MSP movement and to estimate a level of microaccelerations (microgravitations) onboard during flight, and have provided precision time-position binding of the research experiments. The data from the equipments transmitted on the telemetering channel have allowed testing the information technologies of virtual support of experiments in space. Flight testing of the equipment has allowed make a conclusion on usefulness of accommodation onboard the small-sized auxiliary navigating system focused for work with users of research experiments. The experiments on MSP Foton-M2 are the development of experiments with MIRAGE equipment carried out in 1999 during flight time of MSP Foton-12 [N.D. Semkin, V.V. Ivanov, V.I. Abrushkin, V.L. Balakin, I.V. Belokonov, K.E. Voronov, The experiments with magnetic fields formed by technical equipment inside Foton-12 spacecraft: the results of the MIRAGE experiments, in: Proceedings of International Conference “Scientific and Technological Experiments on Russian Foton/Bion Recoverable Satellites: Results, Problems and Outlooks”, 25–30 June 2000, pp. 116–122; V.L. Balakin, I.V. Belokonov, V.V. Ivanov, “Determination of motion of spacecraft Foton-12 as a result of magnetic fields measurement in MIRAGE experiment”, pp. 231–238 (published in the same place)].Paper is executed within the framework of the grant of the Russian Fund of Fundamental Researches 06-08-00244.     

Ions with a Mass Number of Two in Mass-Spectrometric Experiments aboard Rockets and Satellites

Deuterium ions D⁺and doubly-charged helium ions He⁺⁺have the same mass-to- charge ratio (M/Z= 2) and are not distinguished by the mass-spectrometer. On the basis of analysis of published data, Interkosmos-24satellite data, and theoretical estimations, it is shown that in the ionosphere and plasmasphere the ion with a mass number of two is He⁺⁺and not D⁺, at least at altitudes of higher than 600–800 km. Arguments in favor of the validity of this assumption at lower altitudes are presented. Regularities of the dependence of the N(He⁺⁺)/N(He⁺) ratio on altitude, time of day, season, and solar activity are derived. It is found that in the daytime the N(He⁺⁺)/N(He⁺) ratio decreases with increasing solar activity. The seasonal dependence is most pronounced at nighttime in the altitude interval 1000–2000 km, where this ratio decreases in passing from winter to summer. Peculiarities of the latitude distribution of the absolute and relative values of the He⁺⁺concentration are found in the Interkosmos-24satellite data. On the basis of the same data, a strong longitude effect in the N(He⁺⁺) concentration occurring under certain heliogeophysical conditions is discovered, an effect amplitude attaining one order of magnitude on adjacent orbits. An interpretation of this effect is given.     

Sources and Losses of Energetic Electrons at Low Altitudes from Satellite Data

Fluxes and differential spectra of 0.04–2.0 MeV electrons at low altitudes in the Earth's magnetosphere are considered in comparison with the model spectra AE-8 MAX and AE-8 MIN. Possible causes of the discrepancy between the observational and model spectra are discussed. The coefficients of radial diffusion at various L-shells are estimated for the maximum of solar activity (using the Interkosmos-19 data) and for the minimum of solar activity (using the Kosmos-1686 data) and are derived from the model AE-8. A quantitative evaluation of the electron yield from radial diffusion at low L shells is derived. Ionization losses, Coulomb angle scattering, and resonant wave–particle interaction are considered as the loss mechanisms. A calculation of these losses at the low L-shells is given. The electron distribution at low L-shells is best fitted by a combination of dissipative terms from different models: Coulomb scattering dominates at the lower L-shells (L = 1.2–1.4) and the resonant wave–particle interaction controls the radiation belt maximum and the gap (L = 1.4–2.0).     

Shock–Acoustic Waves Generated during Rocket Launches and Earthquakes

Shock–acoustic waves generated during rocket launches and earthquakes are investigated by a method developed earlier for processing data from a global network of receivers of the GPS navigation system. Disturbances of the total electron content in the ionosphere accompanying the launches of the Proton, Soyuz, and Space Shuttle space vehicles from the Baikonur cosmodrome and Kennedy Space Center launch site in 1998–2000, as well as the earthquakes in Turkey on August 17 and November 12, 1999, were analyzed. It was shown that, regardless of the source type, the impulsive disturbance has the character of an N-wave with a period of 200–360 s and an amplitude exceeding background fluctuations under moderate geomagnetic conditions by a factor of 2–5 as a minimum. The elevation angle of the disturbance wave vector varies from 25° to 65°, and the phase velocity (900–1200 m/s) approaches the speed of sound at heights of the ionospheric F-region maximum. The source location corresponds to a segment of the booster trajectories at a distance of no less than 500–1000 km from the start position and to a flight altitude of no less than 100 km. In the case of earthquakes the source location approximately coincides with the epicenter.     

Orientation of Middle-Scale Structures in the Solar Wind Plasma

An estimation of the value and orientation of the inclination of middle-scale structures in the solar wind plasma is obtained on the basis of time lags of simultaneous correlated measurements on three spacecraft: INTERBALL-1, IMP-8, and WIND. It is shown that middle-scale plasma structures, in the majority of cases, are not perpendicular to the Sun–Earth line, but inclined to it (presumably, in the ecliptic plane), on average, at an angle of approximately 63° (or 27° to the Y _SE axis). However, this inclination is significantly less than the inclination of the Parker spiral for the interplanetary magnetic field (45° at the Earth's orbit).     

The Structure of Ion Spectra in Outer Regions of the Ring Current: The November 13, 1995 Event

We present the results on variations of ion spectra in the energy range from 1 keV to 3 MeV. The spectra measured onboard the INTERBALL Tail Probe satellite on November 13, 1995, during the satellite's passage from the dipole field lines to the lines stretched into the magnetotail are analyzed. The data of the CORALL, DOK-2, and SKA-2 instruments are used to reconstruct the ion spectra. It is shown that, when the ion spectrum along the satellite trajectory is averaged over 2-min intervals, it is smooth up to geocentric distances of 6R _E. With decreasing distances, the form of the particle spectra in the region under consideration remained virtually unchanged (region from L = 11R _E down to L= 6R _E) and only insignificant variations of the energy of the spectral maxima are observed. Possible reasons for the observed regularities are discussed.