Search Publications
Gradient estimation using configurations of two or three spacecraft
Vogt, J.; Blagau, A.; Sorbalo, E. +1 more
The forthcoming three-satellite mission Swarm will allow us to investigate plasma processes and phenomena in the upper ionosphere from an in-situ multi-spacecraft perspective. Since with less than four points in space the spatiotemporal ambiguity cannot be resolved fully, analysis tools for estimating spatial gradients, wave vectors, or boundary p…
Non-adiabatic electron behaviour due to short-scale electric field structures at collisionless shock waves
Schwartz, S. J.; See, V.; Cameron, R. F.
Under sufficiently high electric field gradients, electron behaviour within exactly perpendicular shocks is unstable to the so-called trajectory instability. We extend previous work paying special attention to short-scale, high-amplitude structures as observed within the electric field profile. Via test particle simulations, we show that such stru…
Ion distributions upstream and downstream of the Earth's bow shock: first results from Vlasiator
Vainio, R.; Palmroth, M.; Pokhotelov, D. +3 more
A novel hybrid-Vlasov code, Vlasiator, is developed for global simulations of magnetospheric plasma kinetics. The code is applied to model the collisionless bow shock on scales of the Earth's magnetosphere in two spatial dimensions and three dimensions in velocity space retrieving ion distribution functions over the entire foreshock and magnetoshe…
A statistical study on O+ flux in the dayside magnetosheath
Nilsson, H.; Slapak, R.; Westerberg, L. G.
Studies on terrestrial oxygen ion (O+) escape into the interplanetary space have considered a number of different escape paths. Recent observations however suggest a yet insufficiently investigated additional escape route for hot O+: along open magnetic field lines in the high altitude cusp and mantle. Here we present a stati…
Dynamical processes in space: Cluster results
Escoubet, C. P.; Goldstein, M. L.; Taylor, M. G. G. T. +4 more
After 12 years of operations, the Cluster mission continues to successfully fulfil its scientific objectives. The main goal of the Cluster mission, comprised of four identical spacecraft, is to study in three dimensions small-scale plasma structures in key plasma regions of the Earth's environment: solar wind and bow shock, magnetopause, polar cus…
Cluster as current sheet surveyor in the magnetotail
Nakamura, R.; Baumjohann, W.; Narita, Y.
A novel analysis technique is presented to estimate the current sheet thickness unambiguously and directly, without associating time series data with spatial structure. The technique is a combination of eigenvalue analysis and minimum variance estimator adapted to Harris current sheet geometry, and needs one-time, four-point magnetic field data as…
Cross-field flow and electric potential in a plasma slab
Roth, M.; De Keyser, J.; Echim, M.
We consider cross-field plasma flow inside a field-aligned plasma slab embedded in a uniform background in a 1-dimensional geometry. This situation may arise, for instance, when long-lasting reconnection pulses inject plasma into the inner magnetosphere. The present paper presents a detailed analysis of the structure of the interfaces that separat…
Spatial spreading of magnetospherically reflected chorus elements in the inner magnetosphere
Krasnoselskikh, V.; Breuillard, H.; Agapitov, O. +3 more
Chorus-type whistler waves are known to be generated in the vicinity of the magnetic equator, in the low-density plasma trough region. These wave packets propagate towards the magnetic poles, deviating from the magnetic field lines, before being eventually reflected at higher latitudes. Magnetospheric reflection of whistler waves results in bounce…
Electric potential differences across auroral generator interfaces
De Keyser, J.; Echim, M.
Strong localized high-altitude auroral electric fields, such as those observed by Cluster, are often associated with magnetospheric interfaces. The type of high-altitude electric field profile (monopolar, bipolar, or more complicated) depends on the properties of the plasmas on either side of the interface, as well as on the total electric potenti…
Dispersion relation of electromagnetic ion cyclotron waves using Cluster observations
Walker, S. N.; Balikhin, M. A.; Shprits, Y. Y. +1 more
Multi-point wave observations on Cluster spacecraft are used to infer the dispersion relation of electromagnetic ion cyclotron (EMIC) waves. In this study we use a phase differencing method and observations from STAFF and WHISPER during a well-studied event of 30 March 2002. The phase differencing method requires the knowledge of the direction of …