Search Publications
Outflowing protons and heavy ions as a source for the sub-keV ring current
Lundin, R.; Yamauchi, M.; Dandouras, I. +11 more
Data from the Cluster CIS instrument have been used for studying proton and heavy ion (O+ and He+) characteristics of the sub-keV ring current. Thirteen events with dispersed heavy ions (O+ and He+) were identified out of two years (2001 and 2002) of Cluster data. All events took place during rather geom…
Multispacecraft observations of a prominence eruption
Andretta, V.; Del Zanna, G.; Bemporad, A. +2 more
On 9 May 2007 a prominence eruption occurred at the West limb. Remarkably, the event was observed by the STEREO/EUVI telescopes and by the HINODE/EIS and SOHO/UVCS spectrometers. We present results from all these instruments. High-cadence (~37 s) data from STEREO/EUVI A and B in the He II λ304 line were used to study the 3-D shape and expansion of…
Formation of lower-hybrid solitary structures by modulational interaction between lower-hybrid and dispersive Alfvén waves
André, M.; Stenberg, G.; Eriksson, A. I. +1 more
We investigate the possibility that lower-hybrid solitary structures (LHSS), which are frequently observed in the Earth's ionosphere and magnetosphere, are formed as a result of a modulational interaction between lower-hybrid and dispersive Alfvén waves of initially small amplitude. A large amplitude lower-hybrid pump wave can excite density struc…
Foreshock-like density cavity in the outflow region of magnetotail reconnection
Dandouras, I.; Rème, H.; Cao, J. B. +4 more
During Cluster spacecraft crossing of the magnetotail, a novel density depleted cavity in association with magnetic compressions in the outflow region of reconnection was observed. It contains intense reflected field-aligned particles, which are produced by a generation mechanism similar to that of the terrestrial foreshock, and hence manifests a …
Solar off-limb line widths with SUMER: revised value of the non-thermal velocity and new results
Dolla, L.; Solomon, J.
Alfvén waves and ion-cyclotron absorption of high-frequency waves are frequently brought into models devoted to coronal heating and fast solar-wind acceleration. Signatures of ion-cyclotron resonance have already been observed in situ in the solar wind and in the upper corona. In the lower corona, one can use the line profiles to infer the ion tem…
Mirror waves and mode transition observed in the magnetosheath by Double Star TC-1
Zhang, T. L.; Wang, C.; Volwerk, M. +2 more
The Double Star TC-1 magnetosheath pass on 26 February 2004 is used to investigate magnetic field fluctuations. Strong compressional signatures which last for more than an hour have been found near the magnetopause behind a quasi-perpendicular bow shock. These compressional structures are most likely mirror mode waves. There is a clear wave transi…
Estimating the magnetic energy inside traveling compression regions
Nakamura, R.; Baumjohann, W.; Semenov, V. S. +3 more
We investigate a series of six TCRs (traveling compression regions), appearing in the course of a small substorm on 19 September 2001. Except for two of these TCRs, all Cluster spacecraft were located in the lobe and detected the typical signatures of TCRs, i.e., compressions in |B| and bipolar Bz variations. We use these perturbations …
Velocity fluctuations in polar solar wind: a comparison between different solar cycles
Bavassano, B.; Bruno, R.; D'Amicis, R.
The polar solar wind is a fast, tenuous and steady flow that, with the exception of a relatively short phase around the Sun's activity maximum, fills the high-latitude heliosphere. The polar wind properties have been extensively investigated by Ulysses, the first spacecraft able to perform in-situ measurements in the high-latitude heliosphere. The…
The role of lateral magnetic reconnection in solar eruptive events
Poedts, S.; Bemporad, A.; Soenen, A. +1 more
On 10-11 December 2005 a slow CME occurred in between two coronal streamers in the Western Hemisphere. SOHO/MDI magnetograms show a multipolar magnetic configuration at the photosphere consisting of a complex of active regions located at the CME source and two bipoles at the base of the lateral coronal streamers. White light observations reveal th…
Cluster spacecraft observations of a ULF wave enhanced by Space Plasma Exploration by Active Radar (SPEAR)
Yeoman, T. K.; Fear, R. C.; Badman, S. V. +3 more
Space Plasma Exploration by Active Radar (SPEAR) is a high-latitude ionospheric heating facility capable of exciting ULF waves on local magnetic field lines. We examine an interval from 1 February 2006 when SPEAR was transmitting a 1 Hz modulation signal with a 10 min on-off cycle. Ground magnetometer data indicated that SPEAR modulated currents i…