Electric field and ion density anomalies in the mid latitude ionosphere: Possible connection with earthquakes?

The problem of earthquake prediction has stimulated the search for a correlation between seismic activity and ionospherical anomalies. We found observational evidence of possible earthquake effects in the near-equatorial and low latitude ionosphere; these ionospheric anomalies have been proposed by Gousheva et al. [Gousheva, M., Glavcheva, R., Danov, D., Angelov P., Hristov, P., Influence of earthquakes on the electric field disturbances in the ionosphere on board of the Intercosmos-Bulgaria-1300 satellite. Compt. Rend. Acad. Bulg. Sci. 58 (8) 911–916, 2005a; Gousheva, M., Glavcheva, R., Danov, D., Angelov, P., Hristov, P., Kirov, B., Georgieva, K., Observation from the Intercosmos-Bulgaria-1300 satellite of anomalies associated with seismic activity. In: Poster Proceeding of 2nd International Conference on Recent Advances in Space Technologies: Space in the Service of Society, RAST ‘2005, June 9–11, Istanbul, Turkey, pp. 119–123, 2005b; Gousheva, M., Glavcheva, R., Danov, D., Angelov, P., Hristov, P., Kirov, B., Georgieva, K., Satellite monitoring of anomalous effects in the ionosphere probably related to strong earthquakes. Adv. Space Res. 37 (4), 660–665, 2006]. This paper presents new results from observations of the quasi-static electric field and ion density on board INTERCOSMOS-BULGARIA-1300 satellite in the mid latitude ionosphere above sources of moderate earthquakes. Data from INTERCOSMOS-BULGARIA-1300 satellite and seismic data (World Data Center, Denver, Colorado, USA) for magnetically quiet and medium quiet days are juxtaposed in time-space domain. For satellite’s orbits in the time period 15.09–01.10.1981 an increase in the horizontal and vertical components of the quasi-static electric field and fluctuations of the ion density are observed over zones of forthcoming seismic events. Some similar post effects are observed too. The emphasis of this paper is put on the anomalies which specify the mid latitude ionosphere. The obtained results contain important information because they confirm our previous results for near-equatorial and low latitude regions.     

Effective non-vertical and apparent cutoff rigidities for a cosmic ray latitude survey from Antarctica to Italy in minimum of solar activity

In this paper we will report the results of the computation of cutoff rigidities of vertical and non-vertical incident cosmic ray particles. Non-vertical effective cutoff rigidities have been computed by tracing particle trajectories through the “real” geomagnetic magnetic field comprising the International Geomagnetic Reference Field model (IGRF95, IAGA Division 5 Working Group 8, 1996: Sabaka, T.J., Langel, R.A., Baldwin, R.T., Conrad, J.A. The geomagnetic field, 1900–1995, including the large scale fields from magnetospheric sources and NASA candidate models for the 1995 IGRF revision. J. Geomag. Geoelect. 49, 157–206, 1997.) and the Tsyganenko [Tsyganenko, N.A. A magnetospheric magnetic field model with a warped tail current sheet. Planet. Space Sci. 37, 5–20, 1989.] magnetosphere model. The computation have been done for the backward route (from Antarctica to Italy) of the Italian Antarctic ship survey 1996–1997, for geographic points corresponding to the daily average coordinates of the ship; for zenith angles 15°, 30°, 45° and 60°, and azimuth angles from 0° to 360° in steps of 45°. By means of the obtained non-vertical cutoffs the apparent cutoff rigidities have been calculated. The information on integral multiplicities of secondary neutrons detected by the neutron monitor in dependence of the zenith angle of incoming primary cosmic ray particles have also been used. This information is based on the theoretical calculations of meson-nuclear cascades of primary protons with different rigidities arriving to the Earth’s atmosphere at the zenith angles of 0°, 15°, 30°, 45°, 60° and 75°. The difference between the computed apparent and vertical cutoff rigidities reaches ∼1 GV at rigidities >7–8 GV. At rigidities of 10–16 GV, the difference between the apparent and vertical cutoff rigidities is larger than that obtained earlier by Clem et al. [Clem, J.M., Bieber, J.W., Duldig, M., Evenson, P., Hall, D., Humble, J.E. Contribution of obliquely incident particles to neutron monitor counting rate. J. Geophys. Res. 102, 26919–26926, 1997.] and Dorman et al. [Dorman, L.I., Villoresi, G., Iucci, N., Parisi, M., Tyasto, M.I., Danilova, O.A., Ptitsyna, N.G. Cosmic ray survey to Antarctica and coupling functions for neutron component near solar minimum (1996–1997), 3. Geomagnetic effects and coupling functions. J. Geophys. Res. 105, 21047–21056, 2000.].     

A detailed FLUKA-2005 Monte-Carlo simulation for the ATIC detector

We have performed a detailed Monte-Carlo (MC) simulation for the Advanced Thin Ionization Calorimeter (ATIC) detector using the MC code FLUKA-2005 which is capable of simulating particles up to 10 PeV. The ATIC detector has completed two successful balloon flights from McMurdo, Antarctica lasting a total of more than 35 days. ATIC is designed as a multiple, long duration balloon flight, investigation of the cosmic ray spectra from below 50 GeV to near 100 TeV total energy; using a fully active Bismuth Germanate (BGO) calorimeter. It is equipped with a large mosaic of silicon detector pixels capable of charge identification, and, for particle tracking, three projective layers of x–y scintillator hodoscopes, located above, in the middle and below a 0.75 nuclear interaction length graphite target. Our simulations are part of an analysis package of both nuclear (A) and energy dependences for different nuclei interacting in the ATIC detector. The MC simulates the response of different components of the detector such as the Si-matrix, the scintillator hodoscopes and the BGO calorimeter to various nuclei. We present comparisons of the FLUKA-2005 MC calculations with GEANT calculations and with the ATIC CERN data.     

Spectral characteristics of electron fluxes at L < 2 under the Radiation Belts

The paper presents the analysis of experimental data on electron fluxes with energies 10 keV–10 MeV. Data were obtained during 1978–2005 years in different space experiments (COSMOS-900, MIR Space Station, ACTIVE, SAMPEX, CORONAS-I, CORONAS-F, NOAA POES-17, TATYANA and others). Two areas of electron flux enhancements are studied in the paper: the near-equatorial (L < 1.2) zone and the middle-latitude (1.2 < L < 1.9) zone. It is shown that electron flux enhancements are regularly registered at L < 2 and the observed formations have some typical features. Electron peaks at L < 1.2 appear sporadically while peaks at 1.2 < L < 1.9 are observed regularly. The approximations of spectra by several functions including kappa-function are presented.     

Experimental and theoretical investigation of encounter of a group of particles with protecting elements of spacecraft

We present the results of comprehensive experimental and theoretical investigations of encounter with a barrier of a group of bodies thrown with a high-velocity. Throwing of a group of particles (from two to twelve bodies) was realized on a ballistic route using powder and light-gas units of different calibers in the range of velocities 500–3500 m/s. The process of particle throwing was controlled by acting aerodynamic forces. In experiments on collisions with barriers of a finite thickness (which imitates the protective shield of spacecraft) the number of particles in a homogeneous stream was varied from 2 to 7 at changing the flux density (distances between particles). Experimental data are obtained on variations of the area and mass of back-surface splinters. Numerical calculations simulated a knock of 2 to 4 particles against a barrier in the cases of normal impact and at an angle. The calculations were performed in three-dimensional formulation and applying criteria of complete destruction of material. The appearance of additional destruction centers in the barrier due to mutual influence of particles is revealed. Simple criteria are obtained for estimating the degree of interference of particles and the character of barrier destruction.     

A facility for long-term Mars simulation experiments: the Mars Environmental Simulation Chamber (MESCH)

We describe the design, construction, and pilot operation of a Mars simulation facility comprised of a cryogenic environmental chamber, an atmospheric gas analyzer, and a xenon/mercury discharge source for UV generation. The Mars Environmental Simulation Chamber (MESCH) consists of a double-walled cylindrical chamber. The double wall provides a cooling mantle through which liquid N(2) can be circulated. A load-lock system that consists of a small pressure-exchange chamber, which can be evacuated, allows for the exchange of samples without changing the chamber environment. Fitted within the MESCH is a carousel, which holds up to 10 steel sample tubes. Rotation of the carousel is controlled by an external motor. Each sample in the carousel can be placed at any desired position. Environmental data, such as temperature, pressure, and UV exposure time, are computer logged and used in automated feedback mechanisms, enabling a wide variety of experiments that include time series. Tests of the simulation facility have successfully demonstrated its ability to produce temperature cycles and maintain low temperature (down to -140 degrees C), low atmospheric pressure (5-10 mbar), and a gas composition like that of Mars during long-term experiments.     

Schumann Resonances as a Means of Investigating the Electromagnetic Environment in the Solar System

The propagation of extremely low frequency (ELF, 3 Hz to 3 kHz) radio waves and resonant phenomena in the spherical Earth-ionosphere cavity has been studied for almost fifty years. When such a cavity is excited by naturally occurring broadband electromagnetic radiation, resonances can develop if the equatorial circumference is approximately equal to an integral number of wavelengths of the propagating electromagnetic waves; these are termed Schumann resonances. They provide information not only about thunderstorm and lightning activity on the Earth, and their relation to climate, but also on the properties of the low ionosphere. Similar investigations can be performed for any other planet or satellite, provided that it has an ionosphere. There are important differences between the Earth and other celestial bodies regarding, for example, the surface conductivity, the atmospheric conductivity profile, the geometry of the ionospheric cavity, and the sources of excitation. To a first approximation, the size of the cavity defines the fundamental resonant frequency, the atmospheric electron density profile controls the wave attenuation, the nature of the sources influences the electromagnetic field distribution in the cavity, and the body surface conductivity indicates to what extent the subsurface can be explored. The frequencies and attenuation rates of the principal eigenmodes depend upon the electrical properties of the cavity. Instruments that monitor the electromagnetic environment in the ELF range on the surface, on balloons, or on descent probes provide unique information on the cavity. In this paper, we present Schumann resonance models for selected inner planets, some gaseous giant planets and a few of their satellites. We review the crucial parameters of ELF electromagnetic waves in their atmospheric cavities, namely the electric and magnetic field spectra, their eigenfrequencies, and the associated Q-factors (damping factors). Then we present important information on theoretical developments, on a general model that uses the finite element method and on the parameterization of the cavity. Next we show the distinctiveness of each planetary environment, and discuss how ELF radio wave propagation can contribute to an assessment of the major characteristics of those planetary environments.     

Atmospheric Escape and Evolution of Terrestrial Planets and Satellites

The origin and evolution of Venus’, Earth’s, Mars’ and Titan’s atmospheres are discussed from the time when the active young Sun arrived at the Zero-Age-Main-Sequence. We show that the high EUV flux of the young Sun, depending on the thermospheric composition, the amount of IR-coolers and the mass and size of the planet, could have been responsible that hydrostatic equilibrium was not always maintained and hydrodynamic flow and expansion of the upper atmosphere resulting in adiabatic cooling of the exobase temperature could develop. Furthermore, thermal and various nonthermal atmospheric escape processes influenced the evolution and isotope fractionation of the atmospheres and water inventories of the terrestrial planets and Saturn’s large satellite Titan efficiently.     

Element and Isotopic Fractionation in Closed Magnetic Structures

Recent papers have suggested that the slow solar wind is a super-position of material which is released by reconnection from large coronal loops. This reconnection process is driven by large-scale motions of solar magnetic flux driven by the non-radial expansion of the solar wind from the differentially rotating photosphere into more rigidly rotating coronal holes. The elemental composition of the slow solar wind material is observed to be fractionated and more variable than the fast solar wind from coronal holes. Recently, it has also been reported that fractionation also occurs in 3He/4He. This may be interpreted in the frame-work of an existing model for fractionation on large coronal loops in which wave-particle interactions preferentially heat ions thereby modifying their scale-heights. This revised version was published online in June 2006 with corrections to the Cover Date.     

具有气体动力和物理化学非均匀性的超声速物体绕流(英文)

本文研究的问题是超声速气流流过物体时产生的气体动力和物理化学非均匀性及其对物体空气动力特性的影响。就有关流动非均匀性对温度剖面和密度的效应作了详细探讨,还仔细描述了激波与热层相互干扰时以及在激光辐射脉冲的作用下先行激波生成的情况。值得指出的是超声速气流中加入激光辐射能可能改变流动结构,在局部能量释放区域后面呈现的较高和较低压力,有助于控制飞行中物体的运动。可采取某些措施以改进飞行品质。