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951.
We compared fluxes of the 1–100 MeV solar energetic particles (SEP) measured in the interplanetary medium (ACE) and in the magnetosphere (Universitetsky-Tatiana, POES—in polar caps, and GOES-11—at geosynchronous orbit) during several SEP events of 2005–2006. Peak intensities of the SEP fluxes inside and outside the magnetosphere were compared for each event. It is shown that observed inside-outside difference depends mainly on direction of interplanetary magnetic field (IMF), on degree of the SEP anisotropy (pitch-angle distribution) in IMF, and on distance of the dayside magnetopause from the Earth.  相似文献   
952.
The problem of multisensor detection and high resolution signal state estimation using joint maximum a posteriori detection and high order nonlinear filtering techniques is addressed. The model-based fusion approach offers the potential for increased target resolution in range/Doppler/azimuth space. The approach employs joint detection/estimation filters (JDEF) for target detection and localization. The JDEF approach segments the aggregate nonlinear model over the entire target resolution space into a number of localized nonlinear models by partitioning the resolution space into a number of resolution subcells. This partitioning leads to extremely accurate state estimation. The proposed JDEF approach has a built-in capability for automatic data alignment from multiple sensors, and can be used for centralized, decentralized, and distributed data fusion.  相似文献   
953.
A functional scheme, primary informative signals, a method of electrode system structural parameters synthesis and evaluation of a systematic error of the ion-marking sensor for aerodynamic angle and airspeed measurement are the focus of this paper.  相似文献   
954.
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957.
Many asteroids show indications they have undergone impacts with meteoroid particles having radii between 0.01 m and 1 m. During such impacts, small dust grains will be ejected at the impact site. The possibility of these dust grains (with radii greater than 2.2 μm) forming a halo around a spherical asteroid (such as Ceres) is investigated using standard numerical integration techniques. The orbital elements, positions, and velocities are determined for particles with varying radii taking into account both the influence of gravity, radiation pressure, and the interplanetary magnetic field (for charged particles). Under the influence of these forces it is found that dust grains (under the appropriate conditions) can be injected into orbits with lifetimes in excess of one year. The lifetime of the orbits is shown to be highly dependent on the location of the ejection point as well as the angle between the surface normal and the ejection path. It is also shown that only particles ejected within 10° relative to the surface tangential survive more than a few hours and that the longest-lived particles originate along a line perpendicular to the Ceres-Sun line.  相似文献   
958.
Synchrotron radiation is generated throughout the Milky Way. It fills the sky, and carries with it the imprint of the magnetic field at the point of origin and along the propagation path. Observations of the diffuse polarized radio emission should be able to provide information on Galactic magnetic fields with detail matching the angular resolution of the telescope. I review what has been learned from existing data, but the full potential cannot be realized from current observations because they do not adequately sample the frequency structure of the polarized emission, or they lack information on large-scale structure. I discuss three surveys, each overcoming one of these limitations, and show how use of complementary data on other ISM tracers can help elucidate the role of magnetic fields in interstellar processes. The focus of this review is on the small-scale field, on sizes comparable with the various forms of interaction of stars with their surroundings. The future is bright for this field of research as new telescopes are being built, designed for the survey mode of observation, equipped for wideband, multichannel polarization observations.  相似文献   
959.
This chapter provides an overview of current efforts in the theory and modeling of CMEs. Five key areas are discussed: (1) CME initiation; (2) CME evolution and propagation; (3) the structure of interplanetary CMEs derived from flux rope modeling; (4) CME shock formation in the inner corona; and (5) particle acceleration and transport at CME driven shocks. In the section on CME initiation three contemporary models are highlighted. Two of these focus on how energy stored in the coronal magnetic field can be released violently to drive CMEs. The third model assumes that CMEs can be directly driven by currents from below the photosphere. CMEs evolve considerably as they expand from the magnetically dominated lower corona into the advectively dominated solar wind. The section on evolution and propagation presents two approaches to the problem. One is primarily analytical and focuses on the key physical processes involved. The other is primarily numerical and illustrates the complexity of possible interactions between the CME and the ambient medium. The section on flux rope fitting reviews the accuracy and reliability of various methods. The section on shock formation considers the effect of the rapid decrease in the magnetic field and plasma density with height. Finally, in the section on particle acceleration and transport, some recent developments in the theory of diffusive particle acceleration at CME shocks are discussed. These include efforts to combine self-consistently the process of particle acceleration in the vicinity of the shock with the subsequent escape and transport of particles to distant regions.  相似文献   
960.
The technique of lunar laser ranging (LLR) has for many decades contributed to cutting-edge tests of the fundamental nature of gravity. These include the best tests to date of the strong equivalence principle, the time-rate-of-change of the gravitational constant, gravitomagnetism, the inverse square law, and preferred frame effects. The phenomenologies of each are briefly discussed, followed by an extended discussion of gravitomagnetism. Finally, the new APOLLO project is summarized, which achieves range precision as low as one millimeter.  相似文献   
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