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| Mission extensions approved for science missions |
| ESA's Science Programme Committee has approved the extension of mission operations for XMM-Newton, INTEGRAL, Venus Express, Mars Express and Cluster, as well as the ESA support to the operations of HST and SOHO, until 31 December 2012. An additional year of operations has been approved for Planck. |
| Date: 07 Oct 2009 |
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| Cluster shows how solar wind is heated |
| Using data from the Cluster mission scientists have discovered a mechanism that can account for the heating of the solar wind. Cluster data were used to successfully discriminate between a number of theoretical models and, for the time periods analyzed, a remarkable agreement was found with one model in particular. This result may be applicable in other astrophysical contexts such as the heating of the solar corona. This discovery was highlighted in the 12 June 2009 issue of Physical Review Letters. |
| Date: 16 Jul 2009 |
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| Cluster & Double Star: 1000 publications |
| The Cluster and Double Star missions have reached the milestone of 1000 scientific publications in peer-reviewed journals. After almost nine years in space, the four Cluster spacecraft, which are still in good health, continue to produce new science and cross new regions of space. Last year, 2008, produced the most publications in a single year since launch. |
| Date: 18 Jun 2009 |
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| Monitoring the impact of extreme solar events |
| Combined observations with six spacecraft have allowed scientists to monitor in detail the impact of extreme solar events on the Earth. The study, based on data from four Cluster and two Double Star spacecraft, demonstrated that the typical ion composition observed in the near-Earth environment was drastically modified by extreme solar events and that the magnetosphere became extremely compressed. In situ observations of such changes provide vital information for models of our near-Earth environment where commercial and military spacecraft orbit. |
| Date: 29 Apr 2009 |
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| Cluster's insight into space turbulence |
| The four satellites of ESA's Cluster mission have revealed, for the first time, how turbulence develops in space just outside the Earth's magnetic environment. This result improves the understanding of turbulence, a key physical process by which energy throughout the Universe is transported from large scales at which it is input, to small scales where it is dissipated. |
| Date: 25 Mar 2009 |
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| ESA extends missions studying Mars, Venus and Earth's magnetosphere |
ESA's Science Programme Committee has extended the operations of ESA's Mars Express, Venus Express and Cluster missions until 31 December 2009. The decision to extend the three successful missions was taken on 4 February this year.
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| Date: 09 Feb 2009 |
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| Cluster detects invisible escaping ions |
| For the first time, it has been possible to quantify the amount of hydrogen naturally escaping each year from the Earth's atmosphere. This hydrogen outflow has been shown to be of the order of thousands of tons. The result was obtained by applying a new analytical method to a unique set of electric field data collected by the European Space Agency's Cluster mission. The escaping hydrogen has previously been invisible to classical particle detectors on satellites due to its very low energy.
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| Date: 14 Jan 2009 |
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| The science of space weather |
| On 26 November 2008, the Ministers in charge of space activities in the European Space Agency's eighteen Member States and Canada subscribed to the start of a new programme called Space Situational Awareness. The purpose of this programme is to help protect European space systems against debris and the influence of adverse space weather. But what is the science behind space weather?
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| Date: 15 Dec 2008 |
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| Looking at Jupiter to understand Earth |
| Magnetic substorms observed at Jupiter have recently been compared with those that occur at Earth, shedding new light on this phenomenon. This study was based on data obtained with the ESA Cluster and NASA Galileo spacecraft. |
| Date: 05 Dec 2008 |
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| Highlights from Cluster-THEMIS workshop |
| Nearly 120 space scientists from around the world participated in the First Joint Cluster-THEMIS workshop held at the University of New Hampshire (Durham, USA) from 23 to 26 September 2008. The purpose of the meeting was to discuss recent results obtained by these two missions and to foster cooperation. |
| Date: 17 Oct 2008 |
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| Cluster examines Earth-escaping ions |
| Oxygen ions are constantly escaping from the Earth's upper atmosphere through the magnetic polar caps. This has long been observed but the underlying mechanism has eluded scientists - until now. A recent study reports the first experimental assessment of a physical mechanism that makes a significant contribution to the acceleration of oxygen ions towards the centre of the terrestrial magnetic tail, along magnetic field lines. This assessment was made possible as a result of several years of data collected by the European Space Agency's Cluster mission. |
| Date: 27 Aug 2008 |
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| Electron trapping within reconnection |
| A 3-dimensional (3-D) "magnetic snapshot" of the heart of a magnetic reconnection region has been obtained in-situ by the four satellites of the ESA Cluster mission, at one-third of the distance to the Moon from Earth. The snapshot, constructed using a new analysis method, reveals for the first time a 3-D magnetic structure known as a magnetic null pair where two reconnection sites, or nulls, are magnetically linked. The rare occurrence of one of the Cluster satellites passing by one null of the pair has uncovered a new phenomenon where the electrons are temporarily trapped around that null. The electron trapping may ultimately lead to the formation of energetic electron beams, a well-known but poorly understood consequence of reconnection.
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| Date: 11 Aug 2008 |
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| Beamed radio emission from Earth |
| A recent study reveals how the most powerful emission of terrestrial origin, the Auroral Kilometric Radiation (AKR), is beamed into space. This result was obtained using data collected by the four satellites of the Cluster mission. These new data were found to be inconsistent with two leading AKR beaming theories developed 30 years ago, but support a more recent one. The result has important implications for radio studies of planetary magnetospheres, including radio searches for exo-planets. |
| Date: 27 Jun 2008 |
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| Reconnection - Triggered by Whistlers? |
| Some of the most explosive phenomena in the Universe are due to a physical process known as magnetic reconnection. Fundamental aspects of this process are still not fully understood but new advances, using Cluster data, have recently been reported by a team led by scientists from the Chinese Academy of Sciences. |
| Date: 09 Jun 2008 |
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| Solitons found in the magnetopause |
| First observed in the waters of a Scottish canal in 1834, solitary waves or solitons, have nowadays applications across various fields of physics, including optical fibres to enable ultra-fast internet. However, fundamental questions on this phenomenon remain open. In a recent article published in Physical Review Letters, the spontaneous formation of zonal mode solitary waves at the border of the Earth's magnetosphere, the magnetopause, is reported and explained. Although different types of solitons have been observed in space previously (see references), this paper reports, for the first time, a direct comparison of multi-spacecraft observations and matched numerical modelling of zonal flow solitons, unambiguously showing that these structures penetrate down the plasma density gradient in the magnetospheric border. |
| Date: 07 Mar 2008 |
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| Cluster result impacts future missions |
| Magnetic reconnection is a universal process able to drive explosive phenomena such as solar flares. At the heart of this process is a small zone called the electron diffusion region, where reconnection is thought to be triggered. In a recent article, scientists report the first observational evidence for the overall size of this region and find that it is 300 times larger than previously thought. This means that future missions will have a much better chance of detecting and resolving this region than previously estimated, profoundly impacting mission design and scientific operations. |
| Date: 23 Jan 2008 |
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| Cluster explains nightside ion beams |
| Understanding how solar material manages to reach the nightside of the Earth and flows back to Earth at high speeds is key to forecast the behaviour of the magnetic environment of the Earth and to protect space-based technologies. A recent study reveals for the first time that the tail of the magnetosphere is a place where ions can get highly accelerated simultaneously at different localized sites distributed along the tail axis. Nearly one hundred cases of such multiple high-speed ion beams were found over three years of data collected by the satellites of the European Space Agency Cluster mission. Altogether these observations fall in agreement with predictions of a theory published 14 years ago, that has recently been revisited. |
| Date: 06 Dec 2007 |
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| Cluster captures the impact of CMEs |
| Solar outbursts, known as Coronal Mass Ejections (CME), can represent a hazard to astronauts, disrupt communications with satellites and affect the magnetic environment of the Earth, called the magnetosphere. A recent article provides new evidence that CMEs can also impact the acceleration of matter near the border of the magnetosphere, to speeds higher than 1000 kms-1. This study compares observations from the four satellites of the ESA/NASA Cluster mission with global simulations of the magnetosphere. The acceleration process found, which is interestingly not related to magnetic reconnection, predicts an altered coupling of these high-speed flows with the magnetosphere. |
| Date: 21 Nov 2007 |
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| Cluster probes generalized Ohm's law in space |
| For the first time, a new element of the generalized Ohm's law has been evaluated in space thanks to data collected by the four satellites of the ESA/NASA Cluster mission. This fundamental law of Physics describes in detail the coupling between charged particles and the magnetic field. Its evaluation is necessary to fully understand explosive phenomena in space such as solar flares or magnetic substorms. Published 28 April 2007 in the Journal of Geophysical Research, a study of the newly measured element of the generalized Ohm's law provides a surprising outcome. |
| Date: 09 Nov 2007 |
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| Cluster monitors convection cells over the polar caps |
| Two papers published in February and July 2007 in Annales Geophysicae have shed new light on the dynamics of convection cells of matter, found at hundreds kilometres altitude over the polar caps. The pattern of these convection cells is intimately linked to the response of the Earth's magnetic environment to solar activity. Six years of data collected in space by the four spacecraft of the Cluster mission were used to derive, for the first time, statistical maps of the convection cells pattern under various solar conditions. |
| Date: 22 Oct 2007 |
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