Search Publications
Pseudo-field line resonances in ground Pc5 pulsation events
Sarafopoulos, D. V.
In this work we study four representative cases of Pc5 ground pulsation events with discrete and remarkably stable frequencies extended at least in a high-latitude range of ~20°; a feature that erroneously gives the impression for an oscillation mode with "one resonant field line". Additionally, the presented events show characteristic changes in …
Magnetospheric plasma boundaries: a test of the frozen-in magnetic field theorem
Lundin, R.; Yamauchi, M.; Sauvaud, J. -A. +1 more
The notion of frozen-in magnetic field originates from H. Alfvén, the result of a work on electromagnetic-hydrodynamic waves published in 1942. After that, the notion of frozen-in magnetic field, or ideal MHD, has become widely used in space plasma physics. The controversy on the applicability of ideal MHD started in the late 1950s and has continu…
Cluster magnetotail observations of a tailward-travelling plasmoid at substorm expansion phase onset and field aligned currents in the plasma sheet boundary layer
Davies, J. A.; Wild, J. A.; Fazakerley, A. N. +15 more
We present data from both ground- and space-based instruments for a substorm event which occurred on 5 October 2002, with an expansion phase onset time of 02:50 UT determined from the ground magnetometer data. During this substorm, the Cluster spacecraft were located around 15 RE downtail, 8 RE from midnight in the pre-midnig…
Large-scale velocity fluctuations in polar solar wind
Bavassano, B.; Bruno, R.; D'Amicis, R.
The 3-D structure of the solar wind varies dramatically along the Sun's activity cycle. In the present paper we focus on some properties of the polar solar wind. This is a fast, teneous, and steady flow (as compared to low-latitude conditions) that fills the high-latitude heliosphere at low solar activity. The polar wind has been extensively inves…
The Chinese ground-based instrumentation in support of the combined Cluster/Double Star satellite measurements
Wu, J.; Liu, R. -Y.; Yang, H. -G. +10 more
Ground-based observations can be used to provide substantial support for Cluster/Double Star measurements and greatly enhance the mission's scientific return. There are six Chinese ground stations involved in coordinated cluster/Double Star and ground-based instrument observations. Among them, the Chinese Zhongshan Station in Antarctica and the Ye…
Fine-time energetic electron behavior observed by Cluster/RAPID in the magnetotail associated with X-line formation and subsequent current disruption
Zong, Q. -G.; Daly, P. W.; Baker, D. N. +3 more
Energetic electrons with 90deg pitch angle have been observed in the magnetotail at ~19 RE near local midnight during the recovery phase of a substorm event on 27 August 2001 (Baker et al., 2002). Based on auroral images Baker et al. (2002) placed the substorm expansion phase between ~04:06:16 and ~04:08:19 UT. The electron enhancements…
The NUADU experiment on TC-2 and the first Energetic Neutral Atom (ENA) images recorded by this instrument
Barabash, S.; Gunell, H.; Brinkfeldt, K. +13 more
The spacecraft potential of Double Star TC-1 is positive in large parts of the orbits due to the photo-effect from solar EUV irradiation. These positive potentials typically disturb low energy plasma measurements on board. The potential can be reduced, and thereby the particle measurements improved, by emitting a positive ion beam. This method has…
First results of Chinese particle instruments in the Double Star Program
Dandouras, I.; Zhao, H.; Cao, J. B. +15 more
Double Star Program (DSP) aims to investigate the trigger mechanism and physical models of geomagnetic storms and substorms. The DSP involves two satellites: the equatorial satellite of DSP (TC-1 in China) and the polar satellite of DSP (TC-2 in China). On board the two satellites of TC-1 and TC-2, there are four kinds of particle instruments deve…
Flux pile-up and plasma depletion at the high latitude dayside magnetopause during southward interplanetary magnetic field: a cluster event study
Balogh, A.; Lavraud, B.; Rème, H. +3 more
An event of strong flux pile-up and plasma depletion at the high latitude magnetopause tailward of the cusp has been analyzed based on observations by the suite of Cluster spacecraft. The multi-satellite analysis facilitates the separation of temporal and spatial features and provides a direct estimate for the strength of the plasma depletion laye…
Correlation between ground-based observations of substorm signatures and magnetotail dynamics
Lester, M.; Owen, C. J.; Dunlop, M. +8 more
We present a substorm event study using the four Cluster spacecraft in combination with ground-based instruments, in order to perform simultaneous observations in the ionosphere and magnetotail. We show good correlation between substorm signatures on the ground and in the magnetotail, even though data from the northern-ground and southern-tail hem…