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801.
文章以武器装备体系(Weapon System-of-Systems,WSoS)发展论证需求为牵引,结合现代战争复杂电磁环境下武器装备体系特点,综合考虑武器装备体系效能评估方法,采用我国原创的可拓学理论,从定性与定量两个角度对武器装备体系效能进行评估,结合层次分析法、Delphi法,建立武器装备体系效能评估模型,利用Matlab进行实例仿真实验,表明该方法能够根据隶属等级对武器装备体系效能进行评估,并可分析得出二级指标的弱项,对各指标的优化具有指导作用。 相似文献
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S. Savin L. Zelenyi N. Maynard I. Sandahl H. Kawano C. T. Russell S. Romanov E. Amata L. Avanov J. Blecki J. Buechner G. Consolini G. Gustafsson S. Klimov F. Marcucci Z. Nemecek B. Nikutowski J. Pickett J. L. Rauch J. Safrankova A. Skalsky V. Smirnov K. Stasiewicz P. Song J. G. Trotignon Yu. Yermolaev 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2002,30(12):2821-2830
Multi-spacecraft tracing of the high latitude magnetopause (MP) and boundary layers and Interball-1 statistics indicate that:
- 1. (a) The turbulent boundary layer (TBL) is a persistent feature in the region of the cusp and ‘sash’, a noticeable part of the disturbances weakly depends on the interplanetary magnetic field By component; TBL is a major site for magnetosheath (MSH) plasma penetration inside the magnetosphere through percolation and local reconnection.
- 2. (b) The TBL disturbances are mainly inherent with the characteristic kinked double-slope spectra and, most probably, 3-wave cascading. The bi-spectral phase coupling indicates self-organization of the TBL as the entire region with features of the non-equilibrium multi-scale and multi-phase system in the near-critical state.
- 3. (c) We've found the different outer cusp topologies in summer/winter periods: the summer cusp throat is open for the decelerated MSH flows, the winter one is closed by the distant MP with a large-scale (several Re) diamagnetic ‘plasma ball’ inside the MP; the ‘ball’ is filled from MSH through patchy merging rather than large-scale reconnection.
- 4. (d) A mechanism for the energy release and mass inflow is the local TBL reconnection, which operates at the larger scales for the average anti-parallel fields and at the smaller scales for the nonlinear fluctuating fields; the latter is operative throughout the TBL. The remote from TBL anti-parallel reconnection seems to happen independently.
References
Chen, J., Fritz, T.A., Sheldon, R.B., Spencer, H.E., Spjeldvik, W.N. et al., 1997. Temporary confined population in the polar cap during the August 27, 1996 geomagnetic field distortion period. Geophys. Res. Lett. 24, p. 1447. Full Text via CrossRef | View Record in Scopus | Cited By in Scopus (51)
Chen, J. and Fritz, T.A., 1998. Correlation of cusp MeV helium with turbulent ULF power spectra and its implications. Geophys. Res. Lett. 25, p. 4113. Full Text via CrossRef | View Record in Scopus | Cited By in Scopus (34)
Consolini, G. and Lui, A.T., 2000. Symmetry breaking and nonlinear wave-wave interaction in current disruption: possible evidence for a phase transition. In: Magnetospheric Current SystemsGeophysical Monograph 118, American Geophysical Union, Washington D.C., pp. 395–401.
Dubinin, E., Skalsky, A., Song, P., Savin, S., Kozyra, J. et al., 2001. Polar-Interball coordinated observations of plasma characteristics in the region of the northern and southern distant cusps. J. Geophys. Res. accepted .
Fedorov, A., Dubinin, E., Song, P., Budnick, E., Larson, P. and Sauvaud, J.A., 2000. Characteristics of the exterior cusp for steady southward IMF: Interball observations. J. Geophys. Res. 105, pp. 15,945–15,957.
Fritz, T.A., Chen, J. and Sheldon, R.B., 2000. The role of the cusp as a source for magnetospheric particles: a new paradigm?. Adv. Space Res. 25, pp. 1445–1457. Article | PDF (871 K)
| View Record in Scopus | Cited By in Scopus (18)
Haerendel, G. and Paschmann, G., 1975. Entry of solar wind plasma into the magnetosphere. In: Hultqvist, B. and Stenflo, L., Editors, 1975. Physics of the Hot Plasma in the Magnetosphere, Plenum, NY, p. 23.
Haerendel, G., 1978. Microscopic plasma processes related to reconnection. J. Atmos. Terr. Phys. 40, pp. 343–353. Abstract | PDF (1141 K)
| View Record in Scopus | Cited By in Scopus (27)
Klimov, S. et al., 1997. ASPI Experiment: Measurements of Fields and Waves Onboard the INTERBALL-1 Spacecraft. Ann. Geophys. 15, pp. 514–527. Full Text via CrossRef | View Record in Scopus | Cited By in Scopus (88)
Kuznetsova, M.M. and Zelenyi, L.M., 1990. The theory of FTE: Stochastic percolation model. In: Russell, C.T., Priest, E.R. and Lee, L.C., Editors, 1990. Physics of Magnetic Flux RopesAmerican Geophysical Union, pp. 473–488.
La Belle-Hamer, A.L., Otto, A. and Lee, L.C., 1995. Magnetic reconnection in the presence of sheared flow and density asymmetry: application to the Earth's magnetopause. J. Geophys. Res. 100, pp. 11,875–11,889.
Lagoutte, D., Lefeuvre, F. and Hanasz, J., 1989. Application of bi-coherence analysis in study of wave interactions in space plasma. J. Geophys. Res. 94, p. 435. Full Text via CrossRef
Maynard, N.C., Savin, S., Erickson, G.A., Kawano, H. et al., 2001. Observations of fluxes of magnetosheath origin by Polar and Interball at high latitudes behind the terminator-relationships to the magnetospheric “sash”. J. Geophys. Res. 104, pp. 6097–6122. Full Text via CrossRef
Merka, J., Safrankova, J., Nemecek, Z., Fedorov, A., Borodkova, N., Savin, S. and Skalsky, A., 2000. High altitude cusp: Interball observations. Adv. Space Res. 25, pp. 1425–1434. Article | PDF (915 K)
| View Record in Scopus | Cited By in Scopus (22)
Onsager, T.G., Scudder, J., Lockwood, M. and Russell, C.T., 2001. Reconnection at the high latitude magnetopause during northward IMF conditions. J. Geophys. Res. 106, pp. 25,467–25,488.
Romanov, V., Savin, S., Klimov, S., Romanov, S., Yermolaev, Yu., Blecki, J. and Wronowski, R., 1999. Magnetic turbulence at the magnetopause: plasma penetration. J. Tech. Phys. (Poland) 40 1, pp. 329–332.
Safrankova, J., Nemecek, Z., Prech, L., Sauvaud, J.-A. and Wing, S., 2001. The structure of the magnetopause layers at magnetospheric flanks. In: Proceedings of COSPAR/ESA, Colloquium.
Sagdeev, R.Z. and Galeev, A.A., 1969. Nonlinear plasma theory. In: , Benjamin, White Plains, N.Y., p. 6.
Sandahl, I., Popielavska, B., Budnick, E.Yu., Fedorov, A., Savin, S., Safrankova, J. and Nemecek, Z., 2000. The cusp as seen from Interball. In: Proceedings of Cluster II Workshop. Multiscale/Multipoint Plasma MeasurementsESA/SP-499, Imperial College, London, pp. 39–45.
Savin, S.P., Romanov, S.A., Fedorov, A.O., Zelenyi, L., Klimov, S.I. et al., 1998. The cusp/magnetosheath interface on May 29, 1996: Interball-1 and Polar observations. Geoph. Res. Lett. 25, pp. 2963–2966. Full Text via CrossRef | View Record in Scopus | Cited By in Scopus (23)
Savin, S.P., Borodkova, N.L., Budnik, E.Yu., Fedorov, A.O., Klimov, S.I. et al., 1998. Interball tail probe measurements in outer cusp and boundary layers. In: Horwitz, J.L., Gallagher, D.L. and Peterson, W.K., Editors, 1998. Geospace Mass and Energy Flow: Results from the International Solar-Terrestrial Physics ProgramGeophysical Monograph 104, American Geophysical Union, Washington, D.C., pp. 25–44.
Savin, S., Zelenyi, L., Budnik, L., Borodkova, N., Fedorov, A. et al., 1998. Manifestations of Boundary Layer Dynamics in Substrom Activity. Multi Spacecraft Study. In: Kokubun, S. and Kamide, Y., Editors, 1998. SUBSTORM-4, ‘Conf. on Substorms-4’Lake Hamana, Japan: March 9–13, 1998, , Terra Scientific Publ. Co., Tokyo, pp. 125–130.
Savin, S., Budnik, E., Nozdrachev, M., Romanov, V. et al., 1999. On the plasma turbulence and transport at the polar cusp outer border. Chekhoslovak J. Phys. 49 4a, pp. 679–693. View Record in Scopus | Cited By in Scopus (15)
Savin, S., Skalsky, A., Romanov, S., Budnick, E., Borodkova, N., Zelenyi, L. et al., 2000. Outer cusp boundary layer: summer/winter assymetry. In: Proceedings of Symposium ‘From solar corona through interplanetary space into magnetosphere and ionosphere’, Kyiv University, Kyiv, pp. 229–232.
Savin, S., Blecki, J., Pissarenko, N., Lutsenko, V., Kirpichev, I. et al., 2002. Accelerated particles from turbulent boundary layer. In: Proc. of Interball/COSPAR Colloquium ‘Acceleration And Heating In The Magnetosphere’ in press .
Savin, S., Maynard, N., Sandahl, I., Kawano, H., Russell, C.T., Romanov, S., Zelenyi, L. et al., 2002. Magnetosheath/Cusp Interface. Ann. Geophys. submitted .
Siscoe, G.L., Erickson, G.M., Sonnerup, B.U.Ö., Maynard, N.C., Siebert, K.D., Weimer, D.R. and White, W.W., 2001. Magnetospheric sash dependence on IMF direction. Geophys. Res. Lett. in press .
Spreiter, J.R. and Briggs, B.R., 1962. Theoretical determination of the form of the boundary of the solar corpuscular stream produced by interaction with the magnetic dipole field of the Earth. J. Geophys. Res. 67, pp. 37–51. Full Text via CrossRef
Zelenyi, L.M. and Milovanov, A.V., 1998. Multiscale magnetic structure of the distant tail: self-consistent fractal approach. In: New Perspectives on the Earth MagnetotailGeophys. Monograph 105, AGU, Washington DC, pp. 321–338.
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805.
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