Search Publications
Four-point discontinuity observations using Cluster magnetic field data: A statistical survey
Balogh, A.; Neubauer, F. M.; Horbury, T. +1 more
Using magnetic field data from the four Cluster spacecraft between February and May 2001, a detailed statistical analysis of interplanetary discontinuities is accomplished. In order to find the surface normals, we apply three different methods: (1) minimum variance analysis (MVA), (2) cross-product method, and (3) triangulation, the latter being t…
Magnetic turbulence in the plasma sheet
Balogh, A.; Zhang, T. L.; Klecker, B. +9 more
Small-scale magnetic turbulence observed by the Cluster spacecraft in the plasma sheet is investigated by means of a wavelet estimator suitable for detecting distinct scaling characteristics even in noisy measurements. The spectral estimators used for this purpose are affected by a frequency-dependent bias. The variances of the wavelet coefficient…
Cluster observations of hot flow anomalies
Balogh, A.; Dandouras, I.; RèMe, H. +2 more
On 2 April 2002, Cluster entered the solar wind at high northern latitudes and observed a series of disturbances upstream of the bow shock. We suggest that these were signatures of a sequence of hot flow anomalies (HFAs), observed at different stages of development. We estimate the orientation and motion of the HFAs and structures within them usin…
Inferring of flux rope orientation with the minimum variance analysis technique
Fu, S. Y.; Pu, Z. Y.; Zong, Q. G. +3 more
The accuracy in flux rope orientation inference from both the traditional magnetic-field-based minimum variance analysis (BMVA) technique and the current-based MVA (CMVA) approach is examined. Four different flux rope models are used in the MVA test. It is found that the directions of eigenvectors of MVA are critically dependent on the spacecraft …
Cluster observations of finite amplitude Alfvén waves and small-scale magnetic filaments downstream of a quasi-perpendicular shock
Fazakerley, A. N.; Maksimovic, M.; Alexandrova, O. +7 more
The Cluster satellites crossed the Earth's bow shock several times on 31 March 2001. For all these crossings the bow shock was supercritical and quasi-perpendicular. We present here the results of a detailed analysis of the magnetic field fluctuations observed downstream of the shock. We use data from the four Cluster spacecraft to determine the b…
Case studies of the dynamics of ionospheric ions in the Earth's magnetotail
Lundin, R.; Sauvaud, J. -A.; Balogh, A. +19 more
This paper presents case studies of the dynamics of the terrestrial ions in the midplasma sheet and inside the lobes (∼17-19 RE). The high time resolution measurements of H+, He+, and O+ ions made on board Cluster show that these ions are massively injected into the tail during substorms/storms from the …
First comparisons of local ion measurements in the inner magnetosphere with energetic neutral atom magnetospheric image inversions: Cluster-CIS and IMAGE-HENA observations
Dunlop, Malcolm; Balogh, André; Dandouras, Iannis +9 more
Data provided by the CIS (Cluster Ion Spectrometry) instruments on board the Cluster spacecraft are used to survey recent crossings of the inner magnetosphere and ring current. CIS is capable of obtaining full three-dimensional ion distributions (about 0 to 40 keV/q) with one spacecraft spin time resolution and with mass-per-charge composition det…
Walén and slow-mode shock analyses in the near-Earth magnetotail in connection with a substorm onset on 27 August 2001
Balogh, A.; RèMe, H.; Vaivads, A. +6 more
We have examined Cluster spacecraft 1 (C1) magnetic field and particle observations from 27 August 2001 when the Cluster spacecraft separation was less than 0.27 RE and the spacecraft were located near the equatorial plane of the postmidnight magnetotail at xGSM ∼ -19 RE and yGSM ∼ -2.1 RE. A …
Simultaneous observations of field-aligned beams and gyrating ions in the terrestrial foreshock
Dandouras, I.; Klecker, B.; Lucek, E. A. +14 more
We examine an energetic (2-30 keV) upstream ion event presenting a clear double-peak spectrum observed ∼1 RE upstream from the bow shock. The lower-energy (E ∼ 3.5 keV) peak is associated with an ion beam propagating along the magnetic field direction, while the higher-energy (E ∼ 13 keV) peak is associated with gyrating ions having pit…
Motion and orientation of magnetic field dips and peaks in the terrestrial magnetosheath
Balogh, A.; Dandouras, I.; RèMe, H. +2 more
Using data from the four Cluster spacecraft, estimates of the motion of isolated magnetic field dips and peaks in the magnetosheath are presented. Their motion and orientation are deduced using four-spacecraft timing, with typical spacecraft separations of ∼100 km. A set of 39 clear isolated dips and 12 peaks, spread over 4 days, is considered. Th…