Wave generation in the terrestrial magnetosphere

The Hard X-ray Imaging Spectrometer aboard the SMM detected gigantic arches in the corona which are formed or, if preexisting, become excited after major two-ribbon flares. They are seen in 3.5–8 keV X-rays and extend along the H _∥ = 0 line to altitudes between 10⁵ and 2 × 10⁵ km. These arches are stationary and form the base of a stationary type I radio noise storm initiated by the flare. They are visible in X-rays for ten hours or more and may be revived, in temperature, density, and brightness, if another two-ribbon flare appears below them. We suggest that they are built-up through reconnection process during the flare from the upper reconnected loops in the Kopp and Pneuman model. These loops become interconnected along the H _∥ = 0 line in consequence of great shear of the reconnecting loops. Obviously, the coronal transient associated with such flares must be either accomplished prior to the formation of the arch, or it must be formed through a process different from the Anzer-Kopp-Pneuman mechanism. Striking brightness variations occur quasi-periodically in the corona below and above the arch a few hours after the flare. These variations are seen at about the same time in soft X-rays, hard X-rays, and on centimeter microwaves in the low corona, as well as at metric waves in the type I noise-storm region. In spite of their flare-like intensity, however, the variations have little response in the transition layer (O v line) and no response at all in the chromosphere (Hα). We suggest that these semi-periodic brightenings are due to repetitive acceleration processes in plasmoids that encircle the arch perpendicular to the H _∥ = 0 line from the low corona through the noise storm region, being completely detached from the lower atmospheric layers.     

Energetics of terrestrial and Jovian magnetospheres

Energy supply rates to magnetospheres of Earth and Jupiter are estimated on the basis of most recent information on controlling parameters, and these are compared with energy consumption rates inside respective magnetospheres. Dominant role played by the reconnection process is suggested, but the high ejection rate of energetic electrons from the Jovian magnetosphere reported by Conlon (1978) might suggest the importance of the planetary rotation as the energy source.Proceedings of the Symposium on Solar Terrestrial Physics held in Innsbruck, May–June 1978.     

Coronal disturbances and their terrestrial effects

Coronal disturbances lead to geomagnetic storms, proton showers, auroras and a wide variety of other phenomena at Earth. Yet, attempts to link interplanetary and terrestrial phenomena to specific varieties of coronal disturbances have achieved only limited success. Here, several recent approaches to prediction of interplanetary consequences of coronal disturbances are reviewed. The relationships of shocks and energetic particles to coronal transients, of proton events to γ-ray bursts, of proton events to microwave bursts, of geomagnetic storms to filament eruptions and of solar wind speed increases to the flare site magnetic field direction are explored. A new phenomenon, transient coronal holes, is discussed. These voids in the corona appear astride the long decay enhancements (LDE's) of 2–50 Å X-ray emission that follow Hα filament eruptions. The transient holes are similar to long-lived coronal holes, which are the sources of high speed solar wind streams. There is some evidence that transient coronal holes are associated with transient solar wind speed increases.     

The interplanetary magnetic field. Solar origin and terrestrial effects

Many observations related to the large-scale structure of the interplanetary magnetic field, its solar origin and terrestrial effects are discussed. During the period observed by spacecraft the interplanetary field was dominated by a sector structure corotating with the sun in which the field is predominantly away from the sun (on the average in the Archimedes spiral direction) for several days (as observed near the earth), and then toward the sun for several days, etc. The average sector appears to be a coherent entity with internal structure such that its preceding portion is more active than its following portion. Cosmic rays corotate with the interplanetary field, and there are differential flows associated with the sector pattern. Profound effects on geomagnetic activity and the radiation belts are produced as the sector pattern rotates past the earth. The solar origin of the sector pattern is discussed. The solar source may be associated with the large-scale weak background photospheric fields observed with the solar magnetograph. It is suggested that there may be a rather continual relation between this solar structure and terrestrial responses, of which the recurring M-Region geomagnetic storms are just the most prominent example.     

Navigating towards the future: transitioning from terrestrial radio navigation to satellite navigation and airborne surveillance

This paper presents a proposal for transitioning from terrestrial-based navigation aids to implementing satellite and airborne surveillance as the primary navigation means. The transition occurs through several steps. First, the installation and use of modern navigation and surveillance equipment is mandated by the regulatory organizations. The installations should take place in a sequenced fashion to allow time for companies to absorb the initial cost. Next, the existing network of terrestrial navigation aids is down-sized leaving only the areas of heaviest use in service. At this point, the global positioning system (GPS) will be deemed the primary method of terrestrial and oceanic travel. Finally, terrestrial navigation stations will be available around airports and the remaining stations will be put in a standby condition for use in the event of a national emergency. This paper will discuss the security benefits and examples of cost savings through implementation of these steps.     

Comments on the analysis of returned comet samples

It is first argued that, when comet sampled are returned, they should be distributed to individual laboratories for analysis in the way that lunar samples, meteorites, and interplanetary dust particles have been studied in the past. The intellectual ferment engendered by recent discoveries should ensure the viability of groups working in extraterrestrial material research into the indefinite future. Many of the recent discoveries have resulted from application of increasingly sophisticated methods of microanalysis. #the interplay between technological developments and scientific work is underscored and it is argued that increased technical support for extraterrestrial material research should lead to instrumental developments that could have widespread practical applications.A brief review of certain potentially relevant technical developments in other fields is given and it is suggested that microanalytic measurements of extraterrestrial samples at the atom-counting limit appear promising for the future. The special problems raised by the necessity for cryogenic examination of comet samples are briefly discussed and it is concluded that the lack of expertise in this area is a current weakness in the ability of the extraterrestrial material community to handle comet samples. Computer tomography scan images of a dirty snowball are presented to illustrate the importance of developing new methods for comet sample analysis.     

Estimation of the covariance matrix for dependent signal samples:polarization diversity systems

The problem of the estimation of covariance matrices in multichannel radar system when signal samples are statistically dependent is addressed. An optimal maximum likelihood (ML) estimate is derived. Probability characteristics and sensitivity to signal models of the estimate are evaluated for a polarization diversity system     

Concepts for the curation,primary examination,and allocation of comet nucleus samples by a comet sample receiving laboratory

The Comet Nucleus Sample Return Mission ROSETTA, a cornerstone mission of ESA jointly planned with NASA, requires the implementation of a highly sophisticated curatorial facility for the returned samples. A concept for the instrumentation and the mode of operation of a Comet Sample Receiving Laboratory (CSRL) is proposed. The main elements of the facility are: (1) cryogenic evacuated cabinets with robotic manipulators, (2) devices for sample dissection, aliquotisation, phase separation, and thin section preparation, and (3) instrumentation for non-destructive chemical and physical analyses and facilities for destructive mineralogical, textural, and (micro)chemical analyses. It is recommended that a very detailed Primary Sample Examination and Analysis be performed on a small representative fraction of the samples at the P-T-conditions of the parent comet nucleus before sample aliquots are released to Principal Investigators. The CSRL should be staffed with top rank personnel and supervised by an international peer review panel which may also be responsible for the selection of investigators and the allocation of samples.     

Solar variability and minor constituents in the lower thermosphere and in the mesosphere

Space Science Reviews - The variation in the solar irradiance related for example to the 11-year cycle leads to changes in the photodissociation and photo-ionization of the upper and middle...     

Discharges in the Stratosphere and Mesosphere

In the present paper salient features of discharges in the stratosphere and mesosphere (namely sprites, halos, blue starters, blue jets, gigantic jets and elves), are discussed. The electrostatic field due to charge imbalance during lightning processes may lead to stratospheric/mesospheric discharges either through the conventional breakdown based on streamers and leaders or relativistic runaway mechanism. Most (not all) of the observed features of sprites, halos and jets are explained by this processes. Development and evolution of streamers are based on the local transient electrostatic field and available ambient electron density which dictate better probability in favor of positive cloud-to-ground discharges, and thus explains the polarity asymmetry in triggering sprites and streamers. Elves are generated by electromagnetic pulse radiated by return stroke currents of cloud-to-ground/inter-cloud discharges. Generation of the both donut and pancake shape elves are explained. Electrodynamic features of thunderstorms associated with stratospheric/mesospheric discharges are summarized including current and charge moment associated with relevant cloud-to-ground discharges. The hypothesis relating tropospheric generated gravity waves and mesospheric discharges are also discussed. Finally some interesting problems are listed.     

无损检验的现状及未来

介绍了无损检验技术的现状及对未来5～20年发展趋势的分析。无损检验技术用来对零部件进行定量测量,它包括一系列检验方法,如X射线、超声、目视、电磁、声发射、磁粉     

Particle acceleration at the Sun and in the heliosphere

Energetic particles are accelerated in rich profusion at sites throughout the heliosphere. They come from solar flares in the low corona, from shock waves driven outward by coronal mass ejections (CMEs), from planetary magnetospheres and bow shocks. They come from corotating interaction regions (CIRs) produced by high-speed streams in the solar wind, and from the heliospheric termination shock at the outer edge of the heliospheric cavity. We sample many populations near Earth, but can distinguish them readily by their element and isotope abundances, ionization states, energy spectra, angular distributions and time behavior. Remote spacecraft have probed the spatial distributions of the particles and examined new sources in situ. Most acceleration sources can be ‘seen’ only by direct observation of the particles; few photons are produced at these sites. Wave-particle interactions are an essential feature in acceleration sources and, for shock acceleration, new evidence of energetic-proton-generated waves has come from abundance variations and from local cross-field scattering. Element abundances often tell us the physics of the source plasma itself, prior to acceleration. By comparing different populations, we learn more about the sources, and about the physics of acceleration and transport, than we can possibly learn from one source alone. This revised version was published online in August 2006 with corrections to the Cover Date.     

自主创新中的标准化与标准化的创新

阐述了自主创新的重心在于推进科技进步,标准化是支撑科技进步的重要基点之一.标准是创新成果的表现形式和竞争的基础,是创新结果固化与传播的重要载体.加强标准化不会妨碍创新,同时,标准化工作必须开拓创新.     

解析中英创意企业家网络

解析中英创意企业家网络中英创意企业家网络来自广告、建筑、艺术、古董贸易、电脑和视频游戏、手工艺、设计、时尚设计师、电影和影像、音乐、表演艺术、出版、软件和电视和广播的领域:是艺术家(创意人才)和市场(创意消费者)连接起来的桥梁;