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| Technical Review Report - Marco Polo |
| Reference: SRE-PA/2009.069/Marco-Polo This technical review report for the Marco Polo candidate mission presents the outcome of ESA's internal review of this M-class candidate mission in the Cosmic Vision 2015-2025 plan. The review was concluded at the end of the mission assessment phase and carried out in frame of the down-selection to 3 or 4 M-class missions, which will proceed to the definition phase. The main goal of this internal review was to identify the mission's critical issues and associated risks at technical, programmatic and financial level. |
| Publication date: 30 Oct 2009 |
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| Kinetic Alfvén waves turbulence in the Earth's magnetosphere |
| The numerical simulations of the model equation governing the nonlinear dynamics of kinetic Alfvén waves in the intermediate-beta plasmas are performed. When the nonlinearity arises due to the ponderomotive force driven density perturbations of kinetic Alfvén waves, the model equation turns out to be a modified nonlinear Schrödinger equation. This has been solved numerically by using appropriate boundary conditions. The coherent, damped magnetic filaments with turbulent spectra have been observed. Our results reveal the interesting change in spectral index because of the damping effect. The steeper power spectra follow ~k-3.4 scaling. Using the Fokker-Planck equation with the new velocity space diffusion coefficient, we find the distribution function of energetic electrons in these turbulent structures. These turbulent structures can be responsible for plasma heating in Earth's magnetosphere. |
| Publication date: 28 Oct 2009 |
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| Disappearing induced magnetosphere at Venus: Implications for close-in exoplanets |
| The solar wind interaction with a planetary atmosphere produces a magnetosphere-like structure near the planet whether or not the planet has an intrinsic global magnetic field. In the case of planets like Venus or Mars, which have no global intrinsic magnetic field but possess a significant atmosphere, a magnetosphere is induced in the highly conducting ionosphere by the time-varying magnetic field carried by the solar wind. The induced magnetosphere at Venus and Mars is almost a "permanent" feature of the solar wind interaction. Here we report a Venus Express observation of the absence of the dayside part of the induced magnetosphere, when the interplanetary magnetic field (IMF) is nearly aligned with the solar wind flow. Using MHD simulations for this extreme IMF orientation, we examine the global interaction of the solar wind with Venus when the magnetic barrier disappears. Furthermore, we estimate the atmospheric loss under this extreme situation. While this solar wind aligned IMF interaction with a planet case is presently rare, and even rarer over solar system history, it might be an appropriate analogue of the interaction of a stellar wind with close-in exoplanet. Thus the solar wind interaction with Venus under this extreme condition might provide us a natural laboratory for studying the evolution of the atmospheres of "hot Jupiters" as well as close-in "terrestrial" planets. |
| Publication date: 27 Oct 2009 |
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| Astronomy & Astrophysics special issue - The CoRoT space mission: early results |
This A&A special issue is devoted to the CoRoT (Convection, Rotation & planetary
Transits) space mission. Launched on 27 December 2006, the satellite moves in a polar circular
orbit, and the CCD camera of its 27-cm telescope measures stellar-brightness variations with µmag
precision in equatorial fields close to the galactic plane.
The main science goals of CoRoT are to discover exoplanets by the transit method and detect
seismic waves in stars across the entire Hertzsprung-Russell diagram. Objectives also include the
study of stellar activity, stellar rotation, and eclipsing multiple systems.The first results obtained
with CoRoT in all these scientific areas are discussed in the pages of this special issue. |
| Publication date: 22 Oct 2009 |
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| PLATO Mission Assessment Study - Executive Summary (Astrium) |
| The PLATO Mission Assessment Study is the industrial part of the PLATO assessment phase. Two parallel 1-year assessment studies have been concluded. This report is the executive summary for the study performed by EADS-Astrium |
| Publication date: 20 Oct 2009 |
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| Universality of Solar-Wind Turbulent Spectrum from MHD to Electron Scales |
| To investigate the universality of magnetic turbulence in space plasmas, we analyze seven time periods in the free solar wind under different plasma conditions. Three instruments on Cluster spacecraft operating in different frequency ranges give us the possibility to resolve spectra up to 300 Hz. We show that the spectra form a quasiuniversal spectrum following the Kolmogorov's law ~k-5/3 at MHD scales, a ~k-2.8 power law at ion scales, and an exponential ~exp[-sqrt(k rhoe)] at scales k rhoe~[0.1,1], where rhoe is the electron gyroradius. This is the first observation of an exponential magnetic spectrum in space plasmas that may indicate the onset of dissipation. We distinguish for the first time between the role of different spatial kinetic plasma scales and show that the electron Larmor radius plays the role of a dissipation scale in space plasma turbulence. |
| Publication date: 14 Oct 2009 |
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| Energetic electron response to ULF waves induced by interplanetary shocks in the outer radiation belt |
| Strong interplanetary shock interactions with the Earth's magnetosphere have great impacts on energetic particle dynamics in the magnetosphere. An interplanetary shock on 7 November 2004 (with the maximum solar wind dynamic pressure of ~70 nPa) was observed by the Cluster constellation to induce significant ULF waves in the plasmasphere boundary, and energetic electrons (up to 2 MeV) were almost simultaneously accelerated when the interplanetary shock impinged upon the magnetosphere. In this paper, the relationship between the energetic electron bursts and the large shock-induced ULF waves is studied. It is shown that the energetic electrons could be accelerated and decelerated by the observed ULF wave electric fields, and the distinct wave number of the poloidal and toroidal waves at different locations also indicates the different energy ranges of electrons resonating with these waves. For comparison, a rather weak interplanetary shock on 30 August 2001 (dynamic pressure ~2.7 nPa) is also investigated. It is found that interplanetary shocks or solar wind pressure pulses with even small dynamic pressure change can have a nonnegligible role in the radiation belt dynamics. |
| Publication date: 10 Oct 2009 |
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| Kinetic theory for the ion humps at the foot of the Earth's bow shock |
| The nonlinear kinetic theory is presented for the ion acoustic perturbations at the foot of the Earth's quasiperpendicular bow shock, that is characterized by weakly magnetized electrons and unmagnetized ions. The streaming ions, due to the reflection of the solar wind ions from the shock, provide the free energy source for the linear instability of the acoustic wave. In the fully nonlinear regime, a coherent localized solution is found in the form of a stationary ion hump, which is traveling with the velocity close to the phase velocity of the linear mode. The structure is supported by the nonlinearities coming from the increased population of the resonant beam ions, trapped in the self-consistent potential. As their size in the direction perpendicular to the local magnetic field is somewhat smaller that the electron Larmor radius and much larger that the Debye length, their spatial properties are determined by the effects of the magnetic field on weakly magnetized electrons. These coherent structures provide a theoretical explanation for the bipolar electric pulses, observed upstream of the shock by Polar and Cluster satellite missions. |
| Publication date: 05 Oct 2009 |
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| Technical Review Report - Cross-Scale |
| Reference: SRE/PA/2009/068 This technical review report for the Cross-Scale candidate mission presents the outcome of ESA's internal review of this M-class candidate mission in the Cosmic Vision 2015-2025 plan. The review was concluded at the end of the mission assessment phase and carried out in frame of the down-selection to 3 or 4 M-class missions, which will proceed to the definition phase. The main goal of this internal review was to identify the mission's critical issues and associated risks at technical, programmatic and financial level. |
| Publication date: 05 Oct 2009 |
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| PRODEX Programme and ESA |
Presentation of the PRODEX Programme and its position within ESA to the Greek scientific community, given at the Hellenic Astronomical Conference in Athens, which was held on 4 September 2009.
Main topics covered:
- PRODEX - Position within ESA
- PRODEX - Introduction
- PRODEX - Its framework
- PRODEX - Which topics?
- PRODEX - How does it work?
- PRODEX - The running projects
- PRODEX - The people
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| Publication date: 01 Oct 2009 |
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| Euclid Mission Assessment Study - Executive Summary (EADS Astrium) |
| The Euclid Mission Assessment Study is the industrial part of the Euclid assessment phase. The study has been performed by Astrium from September 2008 to September 2009 and is intended for space segment definition and programmatic evaluation. The prime responsibility is with Astrium GmbH (Friedrichshafen, Germany) with support from Astrium SAS (Toulouse, France) and Astrium Ltd (Stevenage, UK). |
| Publication date: 30 Sep 2009 |
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| Technical Review Report - Solar Orbiter |
| Reference: SRE-PA/2009/90 This technical review report for the Solar Orbiter candidate mission presents the outcome of ESA's internal review of this M-class candidate mission in the Cosmic Vision 2015-2025 plan. The review was concluded at the end of the mission assessment phase and carried out in frame of the down-selection to 3 or 4 M-class missions, which will proceed to the definition phase. The main goal of this internal review was to identify the mission's critical issues and associated risks at technical, programmatic and financial level.
Note: This report has been superseded by the Solar Orbiter definition study report (Red Book), released in July 2011, which is linked from the right-hand menu. |
| Publication date: 30 Sep 2009 |
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| Plasma transport in the magnetotail lobes |
| The Earth's magnetosphere is populated by particles originating from the solar wind and the terrestrial ionosphere. A substantial fraction of the plasma from these sources are convected through the magnetotail lobes. In this paper, we present a statistical study of convective plasma transport through the Earth's magnetotail lobes for various geomagnetic conditions. The results are based on a combination of density measurements from the Electric Field and Waves Experiment (EFW) and convection velocities from the Electron Drift Instrument (EDI) on board the Cluster spacecraft. The results show that variations in the plasma flow is primarily attributed to changes in the convection velocity, whereas the plasma density remains fairly constant and shows little correlation with geomagnetic activity. During disturbed conditions there is also an increased abundance of heavier ions, which combined with enhanced convection, cause an accentuation of the mass flow. The convective transport is much slower than the field aligned transport. A substantial amount of plasma therefore escape downtail without ever reaching the central plasma sheet. |
| Publication date: 28 Sep 2009 |
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| On the triggering of auroral substorms by northward turnings of the interplanetary magnetic field |
| Some studies over the last decade have indicated that the instability responsible for substorm expansion phase onset may require an external trigger such as a northward turning of the interplanetary magnetic field (IMF). Statistical investigations have lead to contrasting interpretations regarding the relationship between proposed solar wind triggers and substorm onsets identified from geomagnetic data. We therefore present the results of a study into the possible triggering of 260 substorms between 2001-2005, exploiting data from the Cluster and IMAGE satellite missions. We find that only a small fraction (<25%) of the substorms studied are associated with northward turnings of the IMF. However, the majority of the observed onsets are associated with a growth phase characterised using a subset of the criteria employed to define northward-turning IMF triggers. Based upon a case-by-case investigation and the results of an analysis using the statistics of point processes, we conclude that northward-turning structures in the IMF, while sometimes coinciding with the initial phase of individual substorms, are not required to trigger the magnetospheric instability associated with substorm expansion phase onset. |
| Publication date: 25 Sep 2009 |
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| A mechanism for electrostatic solitary structures in the Earth's magnetosheath |
| Electrostatic solitary waves (ESWs) have been observed in the Earth's magnetosheath region by Cluster. A mechanism for the generation of these structures in terms of electron-acoustic solitons and double layers is discussed. The model simulates the magnetosheath plasma by a four-component plasma system consisting of core electrons, two counterstreaming electron beams, and one type of ions. The analysis is based on the fluid equations and the Poisson equation, and employs the Sagdeev pseudopotential techniques to investigate the solitary waves. The electric field amplitudes, the time durations, and the propagation speeds of the solitary structures predicted by the model are in good agreement with the observed electric fields, pulse widths, and speeds of the electrostatic bipolar pulses. |
| Publication date: 24 Sep 2009 |
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| Marco Polo Assessment Study - Executive Summary Report |
Executive Summary of the mission study by OHB-System AG (Reference: MPL-OHB-TN-014). This executive summary presents the results of the Marco Polo study performed under ESA contract by the industrial team led by OHB-System AG, for an ESA-defined scenario. Possible collaboration schemes associated with this scenario are not addressed here. The results presented address the mission and system design of the ESA space element of the Marco Polo mission including the analysis of critical technologies required for this ambitious mission.
The industrial team was led by OHB-System AG and included the following partners:
- GMV S.A. - focussing on mission analysis and GNC technologies
- Sener S.A. - focussing on landing and sample acquisition technologies
- Aero Sekur S.p.A. - focussing on high speed re-entry technologies
- QinetiQ Ltd - providing consultancy in the area of electric propulsion
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| Publication date: 22 Sep 2009 |
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| Comparison of HIPWAC and Mars Express SPICAM observations of ozone on Mars 2006-2008 and variation from 1993 IRHS observations |
| Ozone is a tracer of photochemistry in the atmosphere of Mars and an observable used to test predictions of photochemical models. We present a comparison of retrieved ozone abundances on Mars using ground-based infrared heterodyne measurements by NASA Goddard Space Flight Center's Heterodyne Instrument for Planetary Wind And Composition (HIPWAC) and space-based Mars Express Spectroscopy for the Investigation of the Characteristics of the Atmosphere of Mars (SPICAM) ultraviolet measurements. Ozone retrievals from simultaneous measurements in February 2008 were very consistent (0.8 micron-atm), as were measurements made close in time (ranging from <1 to >8 micron-atm) during this period and during opportunities in October 2006 and February 2007. The consistency of retrievals from the two different observational techniques supports combining the measurements for testing photochemistry-coupled general circulation models and for investigating variability over the long-term between spacecraft missions. Quantitative comparison with ground-based measurements by NASA/GSFC's Infrared Heterodyne Spectrometer (IRHS) in 1993 reveals 2-4 times more ozone at low latitudes than in 2008 at the same season, and such variability was not evident over the shorter period of the Mars Express mission. This variability may be due to cloud activity. |
| Publication date: 15 Sep 2009 |
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| SPICA Telescope Assessment Study - Executive Summary (EADS Astrium) |
| Reference: INSF.TCN.ASF.SPICA.00021 SPICA is a JAXA led astronomical mission. The ESA contribution to the SPICA mission, mainly entailing the provision of the cryogenic telescope assembly, is a M-class candidate in the Cosmic Vision 2015-2025 Plan.
This document provides a summary of the work performed between August 2008 and September 2009 as part of the SPICA assessment phase study. |
| Publication date: 15 Sep 2009 |
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| An Ultramassive, Fast-Spinning White Dwarf in a Peculiar Binary System |
| White dwarfs typically have masses in a narrow range centered at about 0.6 solar mass (M). Only a few ultramassive white dwarfs (mass > 1.2 M) are known. Those in binary systems are of particular interest, because a small amount of accreted mass could drive them above the Chandrasekhar limit, beyond which they become gravitationally unstable. Using data from the X-ray multimirror mission (XMM)-Newton satellite, we show that the x-ray pulsator RX J0648.0-4418 is a white dwarf with mass > 1.2 M, based on dynamical measurements only. This ultramassive white dwarf in a post-common envelope binary with a hot subdwarf can reach the Chandrasekhar limit, and possibly explode as a type Ia supernova, when its helium-rich companion will transfer mass at an increased rate through Roche lobe overflow. |
| Publication date: 04 Sep 2009 |
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| Untwisting magnetospheres of neutron stars |
| Magnetospheres of neutron stars are anchored in the rigid crust and can be twisted by sudden crustal motions ("starquakes"). The twisted magnetosphere does not remain static and gradually untwists, dissipating magnetic energy and producing radiation. The equation describing this evolution is derived, and its solutions are presented. |
| Publication date: 04 Sep 2009 |
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