Search Publications
Statistical model of electron pitch angle diffusion in the outer radiation belt
Krasnoselskikh, V.; Breuillard, H.; Agapitov, O. +2 more
We calculated the bounce averaged electron pitch angle diffusion coefficients ? using the statistical characteristics of lower band chorus activity collected by the Cluster mission from 2001-2009. Nine years of Cluster observations provide the distributions of the θ angle between wave vectors and the background magnetic field; and the distribution…
Observations of oxygen ions in the dayside magnetosheath associated with southward IMF
Nilsson, H.; Slapak, R.; Eriksson, A. +1 more
We present a case study of high energy oxygen ions (O+) observed in the dayside terrestrial magnetosheath, in the southern hemisphere. It is shown that the presence of O+ is strongly correlated to the IMF direction: O+ is observed only for Bz < 0. Three satellites observe O+ immediately at …
A survey of the polar cap density based on Cluster EFW probe measurements: Solar wind and solar irradiation dependence
Haaland, S.; Lybekk, B.; Pedersen, A. +1 more
The plasma density above the Earth's polar caps provide crucial information about the state of the magnetosphere. This region of space is known for its tenuous plasma and extremely low plasma densities, thus making traditional measurements with particle and plasma instruments extremely difficult. A new method based on spacecraft potential measurem…
Multipoint study of magnetosheath magnetic field fluctuations and their relation to the foreshock
Němeček, Z.; Gutynska, O.; Šimůnek, J. +2 more
The magnetosheath is occupied with a variety of low-frequency fluctuations from different sources. Among them, the bow shock and dominantly foreshock processes are often considered as their major contributors. We use distant (Wind) and close (Geotail) interplanetary magnetic field monitors and compare their measurements with simultaneous magnetic …
Determining the full magnetic field gradient from two spacecraft measurements under special constraints
Dunlop, M.; Rong, Z. J.; Shen, C.
In this exploration, it is revealed for the first time that the full magnetic field gradient and current density distribution can be derived from two spacecraft magnetic field measurements under the assumptions that the magnetic field is approximately stationary and force-free, conditions which are particularly relevant to low altitude regions of …
Test of Shi et al. method to infer the magnetic reconnection geometry from spacecraft data: MHD simulation with guide field and antiparallel kinetic simulation
Hesse, M.; Birn, J.; Drake, J. F. +3 more
When analyzing data from an array of spacecraft (such as Cluster or MMS) crossing a site of magnetic reconnection, it is desirable to be able to accurately determine the orientation of the reconnection site. If the reconnection is quasi-two dimensional, there are three key directions, the direction of maximum inhomogeneity (the direction across th…
Electron dynamics in the reconnection ion diffusion region
Fazakerley, A. N.; Daly, P. W.; Nakamura, R. +4 more
We investigate and compare Cluster observations of electron dynamics in different locations of the ion diffusion region for magnetic reconnection in the Earth's magnetotail. On the basis of the 2-D reconstructed magnetic field map from Cluster 1 (C1), we pinpoint that the observed Hall field is ∼6000 km (∼9 ion inertial lengths) away from the magn…
Location of the magnetodisk in the nightside outer magnetosphere of Saturn near equinox based on ion densities
Thomsen, M.; Szego, K.; Bebesi, Z. +4 more
We investigate ion densities derived from measurements by the Cassini Plasma Spectrometer, to determine how these ions are distributed around the magnetodisk of Saturn. The magnetodisk is a variable plasma structure, here we fitted the simple structural model of Arridge et al. (2011) as a reference for the location of the central line of the magne…
Inner magnetosphere currents during the CIR/HSS storm on July 21-23, 2009
Runov, A.; Ganushkina, N. Y.; Dubyagin, S. +2 more
Modeling results of the configuration of the inner magnetosphere current systems, namely, the ring current and the near-Earth tail current, during the July 21-23, 2009 CIR/HSS storm event are presented. We use two different modeling approaches, magnetic field modeling and particle modeling. We perform the magnetospheric magnetic field modeling wit…
The orientation and current density of the magnetotail current sheet: A statistical study of the effect of geomagnetic conditions
Lester, M.; Milan, S. E.; Fear, R. C. +2 more
We examine the orientation and current density of the current sheet during current sheet crossings from Cluster's 2001-2007 tail seasons. The curlometer technique is used to estimate the current density and is combined with Minimum Variance Analysis (MVA) to calculate the direction of the current sheet normal. The SYM-H and AE indices at the time …