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951.
T. Takada R. Nakamura Y. Asano W. Baumjohann A. Runov M. Volwerk T.L. Zhang Z. Vörös K. Keika B. Klecker H. Rème E.A. Lucek C. Carr H.U. Frey 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008,41(10):1585-1592
We examined two consecutive plasma sheet oscillation and dipolarization events observed by Cluster in the magnetotail, which are associated with a pseudo-breakup and a small substorm monitored by the IMAGE spacecraft. Energy input from the solar wind and an associated enhancement of the cross-tail current lead to current sheet thinning and plasma sheet oscillations of 3–5 min periods, while the pseudo-breakups occur during the loading phase within a spatially limited area, accompanied by a localized dipolarization observed by DSP TC1 or GOES 12. That is, the so-called “growth phase” is a preferable condition for both pseudo-breakup and plasma sheet oscillations in the near-Earth magnetotail. One of the plasma sheet oscillation events occurs before the pseudo-breakup, whereas the other takes place after pseudo-breakup. Thus there is no causal relationship between the plasma sheet oscillation events and pseudo-breakup. As for the contribution to the subsequent small substorm, the onset of the small substorm took place where the preceding plasma sheet oscillations can reach the region. 相似文献
952.
The application of frequency-tracking systems to the analysis of laser doppler velocimeter (LDV) signals degraded by background noise has been studied both theoretically and experimentally. Expressions are derived for both the correlation function and the expected value of the phase derivative in the general case of noise off center from the Doppler frequency, and these results are specialized to specific cases of practical interest. Laboratory measurements of output signal-to-noise ratio (SNR) and dc error, for varying input SNR and noise center frequency offset, show good agreement with the theoretical predictions. 相似文献
953.
T. Koryu Ishii Aggarwal D. Combs V.P. 《IEEE transactions on aerospace and electronic systems》1972,(2):191-195
Comparative utilization of a limited amount of energy for continuous and pulse operations was investigated. Under a restriction that the amount of available energy was limited, general equations for operational hours of the energy source for given power output were derived for both continuous and pulse mode operations. This paper points out that due to various adjustable parameters available for pulse mode operation, if properly designed pulse mode operation produces longer utilization of available energy for required output power than continuous mode operation. 相似文献
954.
T. Hirooka M. Yoshikawa S. Miyahara T. Kayahara 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1999,24(12):1637-1640
Radiative and dynamical impacts of Arctic and Antarctic ozone holes on the general circulation are investigated with the aid of a general circulation model developed at Kyushu University. The model includes a simplified ozone photochemistry interactively coupled with radiation and dynamics. Resultant temperature structure consisting of a cooling in the polar lower stratosphere and a warming in the polar upper stratosphere brings about the intensification of the polar night jet. The cooling is caused by the decrease of solar ultraviolet heating due to the ozone depletion, while the warming is caused by adiabatic heating due to the enhancement of downward motion. 相似文献
955.
A high-frequency (HF) aperture was synthesized by receiving ionospherically propagated signals in an airplane. The signals used the one-hop F lower ray mode to propagate a distance of 2600 km and were processed to yield equivalent aperture lengths of 10 km and 70 km. It was shown that apertures of up to 10 km in length could sometimes achieve their ideal free-space directivity without use of ionospheric compensation. 相似文献
956.
A possibility to prevent collisions with the Earth of dangerous celestial bodies by directing at them small asteroids is considered.
It is proposed to solve this problem using a gravitational maneuver near the Earth. 相似文献
957.
Based on the data of numerical simulation of the test stand gas-liquid ejector operation, the fields of gasodynamic flow parameters in the gas flue channel are determined. The test stand operation in real time and processes of interaction between the flow of combustion products and neutralizing liquid are also analyzed. 相似文献
958.
The concept of “space patrol” is considered, aimed at discovering and cataloging the majority of celestial bodies that constitute
a menace for the Earth [1, 2]. The scheme of “optical barrier” formed by telescopes of the space patrol is analyzed, requirements
to the observation system are formulated, and some schemes of sighting the optical barrier region are suggested (for reliable
detection of the celestial bodies approaching the Earth and for determination of their orbits). A comparison is made of capabilities
of electro-jet engines and traditional chemical engines for arrangement of patrol spacecraft constellation in the Earth’s
orbit. 相似文献
959.
Translational-rotational motion of three planets modeled by viscoelastic balls in the gravitational field of mutual attraction
is studied in this paper. The system of equations of motion for the mechanical system under consideration is deduced from
the d’Alembert-Lagrange variational principle. Using the method of separation of motions, an approximate system of ordinary
differential equations, describing the translational-rotational motion of the planets, is obtained with taking into account
perturbations caused by elasticity and dissipation. The found steady-state motion of the system is an analog to triangular
libration points in the classical three-body problem. 相似文献
960.
N. A. Vlasova N. N. Pavlov M. I. Panasyuk N. N. Vedenkin T. A. Ivanova G. P. Lyubimov S. Ya. Reizman V. I. Tulupov 《Cosmic Research》2011,49(6):485-499
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