Search Publications
The distribution of the ring current: Cluster observations
Woodfield, E. E.; Lockwood, M.; Dunlop, M. W. +9 more
Extending previous studies, a full-circle investigation of the ring current has been made using Cluster 4-spacecraft observations near perigee, at times when the Cluster array had relatively small separations and nearly regular tetrahedral configurations, and when the Dst index was greater than -30 nT (non-storm conditions). These observations res…
Accuracy of multi-point boundary crossing time analysis
Haaland, S.; Paschmann, G.; Vogt, J.
Recent multi-spacecraft studies of solar wind discontinuity crossings using the timing (boundary plane triangulation) method gave boundary parameter estimates that are significantly different from those of the well-established single-spacecraft minimum variance analysis (MVA) technique. A large survey of directional discontinuities in Cluster data…
Comparison of accelerated ion populations observed upstream of the bow shocks at Venus and Mars
Coates, A. J.; Fedorov, A.; Barabash, S. +12 more
Foreshock ions are compared between Venus and Mars at energies of 0.6~20 keV using the same ion instrument, the Ion Mass Analyser, on board both Venus Express and Mars Express. Venus Express often observes accelerated protons (2~6 times the solar wind energy) that travel away from the Venus bow shock when the spacecraft location is magnetically co…
Non-stationarity of the quasi-perpendicular bow shock: comparison between Cluster observations and simulations
Scholer, M.; Soucek, J.; Comişel, H. +1 more
We have performed full particle electromagnetic simulations of a quasi-perpendicular shock. The shock parameters have been chosen to be appropriate for the quasi-perpendicular Earth's bow shock observed by Cluster on 24 January 2001 (Lobzin et al., 2007). We have performed two simulations with different ion to electron mass ratio: run 1 with m
O+ heating associated with strong wave activity in the high altitude cusp and mantle
Waara, M.; Nilsson, H.; Slapak, R. +3 more
We use the Cluster spacecraft to study three events with intense waves and energetic oxygen ions (O+) in the high altitude cusp and mantle. The ion energies considered are of the order 1000 eV and higher, observed above an altitude of 8 earth radii together with high wave power at the O+ gyrofrequency. We show that heating by…
Magnetospheric mapping of the dayside UV auroral oval at Saturn using simultaneous HST images, Cassini IMF data, and a global magnetic field model
Belenkaya, E. S.; Nichols, J. D.; Cowley, S. W. H. +2 more
We determine the field-aligned mapping of Saturn's auroras into the magnetosphere by combining UV images of the southern dayside oval obtained by the Hubble Space Telescope (HST) with a global model of the magnetospheric magnetic field. The model is tailored to simulate prevailing conditions in the interplanetary medium, corresponding to high sola…
Analysis of ionospheric electrodynamic parameters on mesoscales - a review of selected techniques using data from ground-based observation networks and satellites
Amm, O.; Vanhamäki, H.
We present a review of selected data-analysis methods that are frequently applied in studies of ionospheric electrodynamics and magnetosphere-ionosphere coupling using ground-based and space-based data sets. Our focus is on methods that are data driven (not simulations or statistical models) and can be used in mesoscale studies, where the analysis…
The statistical studies of the inner boundary of plasma sheet
Dandouras, I.; Cao, J. B.; Ding, W. Z. +4 more
The penetration of plasma sheet ions into the inner magnetosphere is very important to the inner magnetospheric dynamics since plasma sheet ions are one of the major particle sources of ring current during storm times. However, the direct observations of the inner boundary of the plasma sheet are fairly rare due to the limited number of satellites…
The proton pressure tensor as a new proxy of the proton decoupling region in collisionless magnetic reconnection
Lavraud, B.; Belmont, G.; Vaivads, A. +3 more
Cluster data is analyzed to test the proton pressure tensor variations as a proxy of the proton decoupling region in collisionless magnetic reconnection. The Hall electric potential well created in the proton decoupling region results in bounce trajectories of the protons which appears as a characteristic variation of one of the in-plane off-diago…
3-D mesoscale MHD simulations of a cusp-like magnetic configuration: method and first results
Adamson, E.; Nykyri, K.
We present a local mesoscale model of the magnetospheric cusp region with high resolution (up to 300 km). We discuss the construction and implementation of the initial configuration and give a detailed description of the numerical simulation. An overview of simulation results for the case of strongly northward interplanetary magnetic field (IMF) i…