Search Publications
Observations of diffusion in the electron halo and strahl
Goldstein, Melvyn L.; Gurgiolo, Chris
Observations of the three-dimensional solar wind electron velocity distribution functions (VDF) using ϕ-θ plots often show a tongue of electrons that begins at the strahl and stretches toward a new population of electrons, termed the proto-halo, that exists near the projection of the magnetic field opposite that associated with the strahl. The ene…
Energetic ions scattered into the loss cone with observations of the Cluster satellite
Yuan, Zhigang; Xiong, Ying; Wang, Jingfang
In this paper, we report in situ observations by the Cluster spacecraft of energetic ions scattered into the loss cone during the inbound pass from the plasma sheet into the plasmasphere. During the inbound pass of the plasma sheet, Cluster observed the isotropy ratio of energetic ions to gradually decrease from unity and the isotropic boundary ex…
Current sheet flapping in the near-Earth magnetotail: peculiarities of propagation and parallel currents
Nakamura, Rumi; Petrukovich, Anatoly A.; Artemyev, Anton V. +1 more
We consider series of tilted current sheet crossings, corresponding to flapping waves in the near-Earth magnetotail. We analyse Cluster observations from 2005 to 2009, when spacecraft visited the magnetotail neutral plane near X ∈ [ - 17, - 8], Y ∈ [ - 16, - 2] RE (in the GSM system). Large separation of spacecraft allows us …
Wave-particle resonance condition test for ion-kinetic waves in the solar wind
Glassmeier, K. -H.; Marsch, E.; Narita, Y. +3 more
Conditions for the Landau and cyclotron resonances are tested for 543 waves (identified as local peaks in the energy spectra) in the magnetic field fluctuations of the solar wind measured by the Cluster spacecraft on a tetrahedral scale of 100 km. The resonance parameters are evaluated using the frequencies in the plasma rest frame, the parallel c…
Inverse scattering problem in turbulent magnetic fluctuations
Narita, Yasuhito; Baumjohann, Wolfgang; Treumann, Rudolf A.
We apply a particular form of the inverse scattering theory to turbulent magnetic fluctuations in a plasma. In the present note we develop the theory, formulate the magnetic fluctuation problem in terms of its electrodynamic turbulent response function, and reduce it to the solution of a special form of the famous Gelfand-Levitan-Marchenko equatio…
Critical pitch angle for electron acceleration in a collisionless shock layer
Narita, Y.; Motschmann, U.; Comişel, H.
Collisionless shock waves in space and astrophysical plasmas can accelerate electrons along the shock layer by an electrostatic potential, and scatter or reflect electrons back to the upstream region by the amplified magnetic field or turbulent fluctuations. The notion of the critical pitch angle is introduced for non-adiabatic electron accelerati…
Observation of a new type of low-frequency waves at comet 67P/Churyumov-Gerasimenko
Altwegg, K.; Tsurutani, B. T.; Glassmeier, K. -H. +23 more
We report on magnetic field measurements made in the innermost coma of 67P/Churyumov-Gerasimenko in its low-activity state. Quasi-coherent, large-amplitude (δ B/B ~ 1), compressional magnetic field oscillations at ~ 40 mHz dominate the immediate plasma environment of the nucleus. This differs from previously studied cometary interaction regions wh…
Internally and externally induced deformations of the magnetospheric equatorial current as inferred from spacecraft data
Gordeev, E. I.; Tsyganenko, N. A.; Andreeva, V. A.
Based on a data pool of 79 yearly files of space magnetometer data by Polar, Cluster, Geotail, and THEMIS satellites between 1995 and 2013, we developed a new quantitative model of the global shape of the magnetospheric equatorial current sheet as a function of the Earth's dipole tilt angle, solar wind ram pressure, and interplanetary magnetic fie…
The relationship between plasmapause, solar wind and geomagnetic activity between 2007 and 2011
Pierrard, V.; Rauch, J. -L.; Décréau, P. +3 more
Taking advantage of the Cluster satellite mission and especially the observations made by the instrument WHISPER to deduce the electron number density along the orbit of the satellites, we studied the relationships between the plasmapause positions (LPP) and the following LPP indicators: (a) solar wind coupling functions B
The far-ultraviolet main auroral emission at Jupiter - Part 1: Dawn-dusk brightness asymmetries
Khurana, K. K.; Badman, S. V.; Bonfond, B. +6 more
The main auroral emission at Jupiter generally appears as a quasi-closed curtain centered around the magnetic pole. This auroral feature, which accounts for approximately half of the total power emitted by the aurorae in the ultraviolet range, is related to corotation enforcement currents in the middle magnetosphere. Early models for these current…