Abstract. We present multi spacecraft measurements in the magnetosheath (MSH) and in the solar wind (SW) by Interball, Cluster and Polar, demonstrating that coherent structures with magnetosonic Mach number up to 3 -Supermagnetosonic Plasma Streams (SPS) -generate transient and anomalous boundary dynamics, which may cause substantial displacements of the magnetospheric boundaries and the riddling of peripheral boundary layers. In this regard, for the first time, we describe a direct plasma penetration into the flank boundary layers, which is a candidate for being the dominant transport mechanism for disturbed MSH periods.Typically SPS's have a ram pressure exceeding by several times that of the SW and lead to long-range correlations between processes at the bow shock (BS) and at the magnetopause (MP) on one side and between MSH and MP boundary layers on the other side. We demonstrate that SPS's can be observed both near the BS and near the MP and argue that they are often triggered by hot flow anomalies (HFA), which represent local obstacles to the SW flow and can induce the SPS generation as a means for achieving a local flow balance. Finally, we also discuss other causes of SPS's, both SW-induced and intrinsic to the MSH.SPS's appear to be universal means for establishing a new equilibrium between flowing plasmas and may also prove to be important for astrophysical and fusion applications.

Abstract. In this paper, we consider the mechanism of ion acceleration by dipolarization fronts in the Earth's magnetotail. The statistics of dipolarization front observations by Interball-tail have been collected from 1995 to 1998 (51 events). We demonstrate that near dipolarization fronts bursts of energetic ions are often observed with an average energy of about 100-200 keV. We develop the analytical model of the ion resonance interaction with dipolarization fronts to describe the observed acceleration. We compare the model and the observations to estimate the width of fronts along the dawn-dusk direction, R y . The mean value is R y ∼ 6 R E .

Abstract. We systematically study the energetic particle (-•25 to 850 keV) dawn-dusk plasma sheet asymmetry using both ion and electron spectra composed of 5 6 energy channels. These spectra, corresponding to an average duration of-•8 hours, have been provided by the Interball tail probe and cover the extent between 15 and 28 R• away from the Earth. The events are classified in four Y coordinate categories: the "dawnside" with Yas•<-13 R•, the "center dawn" with 0>Y>-13 R•, the "center dusk" with 0 13 R•. The asymmetry is profound between the two extreme dawn-dusk flanks and weaker between the two central plasma sheet regions. In all the energy channels the dusk flank ion fluxes exceed those of electrons. At the dawnside the energetic electron fluxes frequently outnumber those of ions above a bottom energy threshold. During quite times (Kp<2) the ion (electron) fluxes in the duskside (dawnside) plasma sheet exceed by far those in the dawn (dusk) flank. In general, the ion and electron fluxes significantly increase as the Kp index steps upward. However, owing to the dawn-dusk asymmetry, one can observe higher electron fluxes at dawn with low Kp than at dusk with high Kp. On the basis of two case studies, it is shown that ongoing substorm processes and plasma temperature transitions temporarily affect the spatial dawn-dusk asynunetry and the associated spectra. In one case study, via successive spectra it was concluded that the betatron acceleration mechanism is probably the dominant energization process, although the observed spectra did not preserve their spectral shape. This is interpreted as due to the action of energy-dependent large-scale drifts across the tail that strongly modify the initial source spectra. The dawn-dusk asymmetry and all the spectral characteristics from inside the plasma sheet are transmitted out into the magnetosheath, and this may help us (in the future) to discriminate between merging and leakage processes taking place over the magnetopause. PrologueIn this work, past results conceming the dawn-dusk plasma sheet asymmetry are generalized to the full range of energies covered by the Interball tail particle detector. The advantage here is that the whole energetic particle spectrum (composed of •56 points) is available for the first time. Thus this study uses ion and electron spectra to show a more precise picture of energetic particle populations across the tail. The spectra visualize the average spatial distribution of "preexisting populations," i.e., of populations that will be further involved in magnetospheric substorm processes. Then with two illustrative case studies, the temporarily affected dawn-dusk asymmetry is approached. Although the latter study is not thorough, it demonstrates how "the cross-tail large-scale drifts" probably modify the initial spectra produced by Early systematic studies of energetic particle bursts inside the plasma sheet were made mostly using the IMP 7 and 8 spacecraft by Keath et al. [1976], Sarris et al. [1976], Kri...

We present both statistical and case studies of magnetosheath interaction with the high-latitude magnetopause on the basis of Interball-1 and other ISTP spacecraft data. We discuss those data along with recently published results on the topology of cusp-magnetosheath transition and the roles of nonlinear disturbances in mass and energy transfer across the high-latitude magnetopause. For sunward dipole tilts, a cusp throat is magnetically open for direct interaction with the incident flow that results in the creation of a turbulent boundary layer (TBL) over an indented magnetopause and downstream of the cusp. For antisunward tilts, the cusp throat is closed by a smooth magnetopause; demagnetized 'plasma balls' (with scale~few R E , an occurrence rate of~25% and trapped energetic particles) present a major magnetosheath plasma channel just inside the cusp. The flow interacts with the 'plasma balls' via reflected waves, which trigger a chaotization of up to 40% of the upstream kinetic energy. These waves propagate upstream of the TBL and initiate amplification of the existing magnetosheath waves and their cascade-like decays during downstream passage throughout the TBL. The most striking feature of the nonlinear interaction is the appearance of magnetosonic jets, accelerated up to an Alfvenic Mach number of 3. The characteristic impulsive local momentum loss is followed by decelerated Alfvenic flows and modulated by the TBL waves; momentum balance is conserved only on time scales of the Alfvenic flows (1/f A~1 2 min). Wave trains at f A~1 .3 mHz are capable of synchronizing interactions throughout the outer and inner boundary layers. The sonic/Alfvenic flows, bounded by current sheets, control the TBL Surveys in Geophysics (2005) 26: 95-133 Ó Springer 2005 spectral shape and result in non-Gaussian statistical characteristics of the disturbances, indicating the fluctuation intermittency. We suggest that the multi-scale TBL processes play at least a comparable role to that of macro-reconnection (remote from or in the cusp) in solar wind energy transformation and population of the magnetosphere by the magnetosheath plasma. Secondary micro-reconnection constitutes a necessary chain at the small-scale (~ion gyroradius) edge of the TBL cascades. The thick TBL transforms the flow energy, including deceleration and heating of the flow in the open throat, 'plasma ball' and the region downstream of the cusp.

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