Search Publications
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
Recent highlights from Cluster, the first 3-D magnetospheric mission
Escoubet, C. P.; Goldstein, M. L.; Masson, A. +1 more
The Cluster mission has been operated successfully for 14 years. During this time period, the evolution of the orbit has enabled Cluster to sample many more magnetospheric regions than was initially anticipated. So far, the separation of the Cluster spacecraft has been changed more than 30 times and has ranged from a few kilometres up to 36 000 km…
O+ transport in the dayside magnetosheath and its dependence on the IMF direction
Nilsson, H.; Slapak, R.; Larsson, R. +1 more
Recent studies have shown that the escape of oxygen ions (O+) into the magnetosheath along open magnetic field lines from the terrestrial cusp and mantle is significant. We present a study of how O+ transport in the dayside magnetosheath depends on the interplanetary magnetic field (IMF) direction. There are clear asymmetries…
Multi-satellite study of the excitation of Pc3 and Pc4-5 ULF waves and their penetration across the plasmapause during the 2003 Halloween superstorm
Tsinganos, K.; Daglis, I. A.; Mann, I. R. +5 more
We use multi-satellite and ground-based magnetic data to investigate the concurrent characteristics of Pc3 (22-100 mHz) and Pc4-5 (1-22 mHz) ultra-low-frequency (ULF) waves on the 31 October 2003 during the Halloween magnetic superstorm. ULF waves are seen in the Earth's magnetosphere, topside ionosphere, and Earth's surface, enabling an examinati…
Field-aligned chorus wave spectral power in Earth's outer radiation belt
Daly, P. W.; Haaland, S. E.; Kronberg, E. A. +8 more
Chorus-type whistler waves are one of the most intense electromagnetic waves generated naturally in the magnetosphere. These waves have a substantial impact on the radiation belt dynamics as they are thought to contribute to electron acceleration and losses into the ionosphere through resonant wave-particle interaction. Our study is devoted to the…
Outflow of low-energy O+ ion beams observed during periods without substorms
Dandouras, I.; Rème, H.; Parks, G. K. +5 more
Numerous observations have shown that ions flow out of the ionosphere during substorms with more fluxes leaving as the substorm intensity increases (Wilson et al., 2004). In this article we show observations of low-energy (few tens of electron volts) ionospheric ions flowing out periods without substorms, determined using the Wideband Imaging Came…
Non-elliptic wavevector anisotropy for magnetohydrodynamic turbulence
Narita, Y.
A model of non-elliptic wavevector anisotropy is developed for the inertial-range spectrum of magnetohydrodynamic turbulence and is presented in the two-dimensional wavevector domain spanning the directions parallel and perpendicular to the mean magnetic field.
The non-elliptic model is a variation of the elliptic model with different sca…
Experimental test of the ρ(1-α) evolution for rotational discontinuities: cluster magnetopause observations
Marghitu, O.; Klecker, B.; Paschmann, G. +1 more
Rotational discontinuities (RDs) are governed by two relations: the Walén relation predicting that the plasma velocity observed in the deHoffmann-Teller frame equals the local Alfvén velocity and another relation that connects the variation in plasma mass density, ρ, to variations in the pressure anisotropy factor, α, defined as α: ≡(p
The dayside magnetopause location during radial interplanetary magnetic field periods: Cluster observation and model comparison
Wang, H.; Shue, J. -H.; Huang, T. +2 more
The present work has investigated the midlatitudinal magnetopause locations under radial interplanetary field (RIMF) conditions. Among 262 (256) earthward (sunward) RIMF events from years of 2001 to 2009, Cluster satellites have crossed the magnetopause 22(12) times, with 10 (7) events occurring at midlatitudes. The observed midlatitudinal magneto…