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121.
    
The application of chaos theory has become popular to understand the nature of various features of solar activity because most of them are far from regular. The usual approach, however, that is based on finding low-dimensional structures of the underlying processes seems to be successful only in a few exceptional cases, such as in rather coherent phenomena as coronal pulsations. It is important to note that most phenomena in solar radio emission are more complex. We present two kinds of techniques from nonlinear dynamics which can be useful to analyse such phenomena:
  1. Fragmentation processes observed in solar spike events are studied by means of symbolic dynamics methods. Different measures of complexity calculated from such observations reveal that there is some order in this fragmentation.
  2. Bursts are a typical transient phenomenon. To study energization processes causing impulsive microwave bursts, the wavelet analysis is applied. It exhibits structural differences of the pre- and post-impulsive phase in cases where the power spectra of both are not distinct.
  相似文献   
122.
Mercury has a small but intriguing magnetosphere. In this brief review, we discuss some similarities and differences between Mercury’s and Earth’s magnetospheres. In particular, we discuss how electric and magnetic field measurements can be used as a diagnostic tool to improve our understanding of the dynamics of Mercury’s magnetosphere. These points are of interest to the upcoming ESA-JAXA BepiColombo mission to Mercury.  相似文献   
123.
Hans J. Haubold   《Space Policy》2003,19(3):1847-223
UN-affiliated regional centres for space science and technology education are being established or are in operation in Africa (Morocco, Nigeria), Asia and the Pacific (India), Latin America and the Caribbean (Brazil, Mexico), and Western Asia (Jordan). Education curricula at the university level, embracing remote sensing, satellite communications, satellite meteorology, and space science have been developed for these centres. This article briefly reports on the structure of the most recent updated education curricula in the four disciplines that have been made available for implementation in 2002 and 2003, in the six official languages of the United Nations. This is also an effort to bridge the gap between such education curricula as they vary significantly between nations and among educational institutions in nations.  相似文献   
124.
    
Eiges  P. E.  Zastenker  G. N.  Safrankova  J.  Nemecek  Z.  Eismont  N. A. 《Cosmic Research》2001,39(5):432-438
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 2RE.  相似文献   
125.
    
The experimental results obtained in experiment “STACO” made on board the Spacelab D-2 are re-visited, with image-analysis tools not then available. The configuration consisted of a liquid bridge between two solid supporting discs. An expected breakage occurred during the experiment. The recorded images are analysed and the measured behaviour compared with the results of a three dimensional model of the liquid dynamics, obtaining a much better fit than with linear models.  相似文献   
126.
Her X-1 has been observed with EXOSAT for one 35d cycle between March 1 and April 5, 1984 at about 4 day intervals. During three observations, absorption dips were encountered showing fluctuations with time scales in the several hundred seconds range. The data are interpreted with a model where random superposition of absorbing blobs or inhomogeneous structures within the accretion disk, in the line of sight, cause these intensity variations. The calculations give a measure of the extent of the disk both in vertical and radial directions.  相似文献   
127.
    
The space shuttle external tank, which consists of a liquid oxygen tank, an intertank structure, and a liquid hydrogen tank, is an expendable structure used for approximately 8.5 min during each launch. A concept for outfitting the liquid oxygen tank-intertank unit for a 12-person lunar habitat is described. The concept utilizes existing structures and openings for both man and equipment access without compromising the structural integrity of the tank. Living quarters, instrumentation, environmental control and life support, thermal control, and propulsion systems are installed at Space Station Freedom. The unmanned habitat is then transported to low lunar orbit and autonomously soft landed on the lunar surface. Design studies indicate that this concept is feasible by the year 2000 with concurrent development of a space transfer vehicle and manned cargo lander for crew changeover and resupply.  相似文献   
128.
This paper analyzes the accuracy of orbit determination calculated by observations of short arcs. In this case, we imposed the condition that the arc length and/or the distribution of arc observations should provide a confident classification of the orbit of a small celestial body allowing one to distinguish a potentially hazardous body, also including a threat of collision.  相似文献   
129.
    
Several years of hourly daily GPS measurements of the vertical total electron content (TEC) and of the equivalent slab thickness made at different European locations are analysed by using the linear regression technique to demonstrate the response of these two ionospheric parameters to seasonal variations. It is found that both TEC and slab thickness are highly correlated with season. Analytical relationships are determined expressing the seasonal dependence of the vertical TEC and of the equivalent slab thickness as a function of the seasonal parameter cos χ at noon in each location.  相似文献   
130.
Active detectors used as radiation monitors in space are not usually able to perform Particle Identification (PID). Common techniques need energy loss spectra with high statistics to estimate ion abundances. The ALTEA-space detector system is a set of silicon strip particle telescopes monitoring the radiation environment on board the International Space Station since July 2006 with real-time telemetry capabilities. Its large geometrical factor due to the concurrent use of six detectors permits the acquisition of good energy loss spectra even in a short period of observation. In this paper we present a novel Fast Probabilistic Particle Identification (FPPI) algorithm developed for the ALTEA data analysis in order to perform nuclear identification with low statistics and, with some limitations, also in real time.  相似文献   
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