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Y. Hobara S.N. Walker M. Dunlop M. Balikhin O.A. Pokhotelov H. Nilsson H. Rme 《Planetary and Space Science》2007,55(15):2257-2260
Using multipoint measurements from the Cluster mission wave identification techniques are applied to observations of ULF waves made in the terrestrial foreshock with the aim of identifying the modes and properties of the waves taking into account the effects of a high beta plasma. The wave properties in the spacecraft and plasma rest frames are experimentally derived using minimum variance analysis. Two waves with periods of 30 and 3 s dominate the dynamic frequency spectrum. The results indicate that these waves propagate in the fast magnetosonic and Alfvén/Ion Cyclotron modes, respectively. Both waves propagate in the upstream direction in the plasma rest frame but are convected downstream in the spacecraft frame. The measured wave properties in the plasma rest frame are in good agreement with those obtained from the theoretical kinetic dispersion relation taking into account the effects of different plasma beta. The dispersion results show a rather significant deviation from fluid model, especially when high beta plasma conditions occur. These experimentally derived foreshock ULF wave properties are in good agreement with previous results but when the effects of a high beta plasma are considered it is not as straight forward to choose the correct wave mode branch. 相似文献
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This work is devoted to the study of the generation of the equatorial noise—electromagnetic emission below the LHR frequency observed near the equatorial plane of the magnetosphere at distances of ~4RE. According to accepted views, the generation of the equatorial noise is related to the instability of ring current protons. In this work, a logarithmic distribution of energetic protons over the magnetic moment with an empty loss cone is proposed, and arguments for the formation of such a distribution are presented. The main result of the work is the calculation and analysis of the instability growth rate of waves forming the equatorial noise. The growth rate obtained in this work significantly differs from that encountered in the literature. 相似文献
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S. Savin L. Zelenyi V. Budaev J. Buechner M. Balikhin V.E. Korepanov V. Kudryashov L. Lezhen Z. Nemecek D. Novikov J.L. Rauch S. Romanov A. Skalsky 《Planetary and Space Science》2011,59(7):606-617
The scientific rationale of the ROY multi-satellite mission addresses multiscale investigations of plasma processes in the key magnetospheric regions with strong plasma gradients, turbulence and magnetic field annihilation in the range from electron inertial length to MHD scales.The main scientific aims of ROY mission include explorations of:
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- turbulence on a non-uniform background as a keystone for transport processes;
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- structures and jets in plasma flows associated with anomalously large concentration of kinetic energy; their impact on the energy balance and boundary formation;
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- transport barriers: plasma separation and mixing, Alfvenic collapse of magnetic field lines and turbulent dissipation of kinetic energy;
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- self-organized versus forced reconnection of magnetic field lines;
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- collisionless shocks, plasma discontinuities and associated particle acceleration processes.
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- simultaneous sampling of low- and high-latitudes magnetopause, bow shock and geomagnetic tail at the same local time;
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- tracing of magnetosheath streamlines from the bow shock to near-Earth geomagnetic tail;
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- passing “through” the SCOPE on the inbound orbit leg;
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- common measurements (with SCOPE and other equatorial spacecraft) at distances of ∼ few thousand km for durations of ∼several hours per orbit.
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Doklady Earth Sciences - 相似文献
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M. A. Balikhin L. J. C. Woolliscroft H. St. C. Alleyne M. Dunlop M. A. Gedalin 《Annales Geophysicae》1997,15(2):143-151
A method of wave mode determination, which was announced in Balikhin and Gedalin, is applied to AMPTE UKS and AMPTE IRM magnetic field measurements downstream of supercritical quasiperpendicular shock. The method is based on the fact that the relation between phase difference of the waves measured by two satellites, Doppler shift equation, the direction of the wave propagation are enough to obtain the dispersion equation of the observed waves. It is shown that the low frequency turbulence mainly consists of waves observed below 1 Hz with a linear dependence between the absolute value of wave vector |k| and the plasma frame wave frequency. The phase velocity of these waves is close to the phase velocity of intermediate waves Vint = Vacos(). 相似文献
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