Institution
Braunschweig University of Technology
Education•Braunschweig, Germany•
About: Braunschweig University of Technology is a education organization based out in Braunschweig, Germany. It is known for research contribution in the topics: Population & Computer science. The organization has 13268 authors who have published 26707 publications receiving 611590 citations.
Papers published on a yearly basis
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TL;DR: In this article, the entanglement properties of a closed chain of harmonic oscillators coupled via a translationally invariant Hamiltonian were studied, where the coupling acts only on the position operators.
Abstract: We study the entanglement properties of a closed chain of harmonic oscillators that are coupled via a translationally invariant Hamiltonian, where the coupling acts only on the position operators We consider the ground state and thermal states of this system, which are Gaussian states The entanglement properties of these states can be completely characterized analytically when one uses the logarithmic negativity as a measure of entanglement
373 citations
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INAF1, Parthenope University of Naples2, Max Planck Society3, Spanish National Research Council4, Aix-Marseille University5, International Space Science Institute6, European Space Agency7, Polish Academy of Sciences8, Uppsala University9, Braunschweig University of Technology10, University of Maryland, College Park11, University of Padua12, Paris Diderot University13, Versailles Saint-Quentin-en-Yvelines University14, European Space Research and Technology Centre15, Selex ES16, University of Trento17, Virginia Tech18, University of Florida19, Open University20, German Aerospace Center21, National Central University22, University of Kent23, University of Granada24, Centre national de la recherche scientifique25, Instituto Nacional de Técnica Aeroespacial26, University of Bern27, Jet Propulsion Laboratory28
TL;DR: In this article, the GIADA (Grain Impact Analyser and Dust Accumulator) experiment on the European Space Agency's Rosetta spacecraft orbiting comet 67P/Churyumov-Gerasimenko was used to detect 35 outflowing grains of mass 10−10 to 10−7 kilograms.
Abstract: Critical measurements for understanding accretion and the dust/gas ratio in the solar nebula, where planets were forming 4.5 billion years ago, are being obtained by the GIADA (Grain Impact Analyser and Dust Accumulator) experiment on the European Space Agency’s Rosetta spacecraft orbiting comet 67P/Churyumov-Gerasimenko. Between 3.6 and 3.4 astronomical units inbound, GIADA and OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) detected 35 outflowing grains of mass 10−10 to 10−7 kilograms, and 48 grains of mass 10−5 to 10−2 kilograms, respectively. Combined with gas data from the MIRO (Microwave Instrument for the Rosetta Orbiter) and ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) instruments, we find a dust/gas mass ratio of 4 ± 2 averaged over the sunlit nucleus surface. A cloud of larger grains also encircles the nucleus in bound orbits from the previous perihelion. The largest orbiting clumps are meter-sized, confirming the dust/gas ratio of 3 inferred at perihelion from models of dust comae and trails.
373 citations
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TL;DR: The Cluster mission as mentioned in this paper provides a new opportunity to study plasma processes and structures in the near-Earth plasma environment using four-point measurements of the magnetic field, which can enable the analysis of the three dimensional structure and dynamics of a range of phenomena which shape the macroscopic properties of the magnetosphere.
Abstract: The Cluster mission provides a new opportunity to study plasma processes and structures in the near-Earth plasma environment Four-point measurements of the magnetic field will enable the analysis of the three dimensional structure and dynamics of a range of phenomena which shape the macroscopic properties of the magnetosphere Difference measurements of the magnetic field data will be combined to derive a range of parameters, such as the current density vector, wave vectors, and discontinuity normals and curvatures, using classical time series analysis techniques iteratively with physical models and simulation of the phenomena encountered along the Cluster orbit The control and understanding of error sources which affect the four-point measurements are integral parts of the analysis techniques to be used The flight instrumentation consists of two, tri-axial fluxgate magnetometers and an on-board data-processing unit on each spacecraft, built using a highly fault-tolerant architecture High vector sample rates (up to 67 vectors s-1) at high resolution (up to 8 pT) are combined with on-board event detection software and a burst memory to capture the signature of a range of dynamic phenomena Data-processing plans are designed to ensure rapid dissemination of magnetic-field data to underpin the collaborative analysis of magnetospheric phenomena encountered by Cluster
373 citations
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TL;DR: In this paper, a flow burst was associated with a clear dipolarization ahead of the high-speed part of the predominantly Earthward directed flow, and the authors found that a ∼2000 km thick dipolarisation front moves Earthward and dawnward with a speed of ∼77 km/s.
Abstract: [1] In this paper we study a flow burst event which took place during enhanced geomagnetic activity on July 22, 2001, when Cluster was located in the postmidnight magnetotail. The flow burst was associated with a clear dipolarization ahead of the high-speed part of the predominantly Earthward directed flow. Based on the analysis of the four spacecraft data, we found that a ∼2000 km thick dipolarization front moves Earthward and dawnward with a speed of ∼77 km/s. The plasma before this front is deflected, consistent with the plasma ahead of a localized plasma bubble centered at midnight side being pushed aside by the moving obstacle. The main body of the high-speed flow is directed mainly parallel to the dipolarization front. These observations indicate that the evolution of the dipolarization front across the tail is directly coupled with the fast flow.
371 citations
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University of California, Los Angeles1, University of California, Berkeley2, Goddard Space Flight Center3, Nagoya University4, Kanazawa University5, Tohoku University6, Korea Astronomy and Space Science Institute7, The Aerospace Corporation8, University of Washington9, Dartmouth College10, Montana State University11, University of California, Santa Cruz12, National Cheng Kung University13, Academia Sinica Institute of Astronomy and Astrophysics14, University of Tokyo15, National Central University16, National Oceanic and Atmospheric Administration17, Cooperative Institute for Research in Environmental Sciences18, Johns Hopkins University Applied Physics Laboratory19, Kyushu University20, Kyoto University21, National Institute of Polar Research22, University of Colorado Boulder23, University of Iowa24, University of New Hampshire25, Southwest Research Institute26, National Center for Atmospheric Research27, Université Paris-Saclay28, Boston University29, Braunschweig University of Technology30, University of Calgary31, University of Graz32, University of Minnesota33
TL;DR: The SPEDAS development history, goals, and current implementation are reviewed, and its “modes of use” are explained with examples geared for users and its technical implementation and requirements with software developers in mind are outlined.
Abstract: With the advent of the Heliophysics/Geospace System Observatory (H/GSO), a complement of multi-spacecraft missions and ground-based observatories to study the space environment, data retrieval, analysis, and visualization of space physics data can be daunting. The Space Physics Environment Data Analysis System (SPEDAS), a grass-roots software development platform (
www.spedas.org
), is now officially supported by NASA Heliophysics as part of its data environment infrastructure. It serves more than a dozen space missions and ground observatories and can integrate the full complement of past and upcoming space physics missions with minimal resources, following clear, simple, and well-proven guidelines. Free, modular and configurable to the needs of individual missions, it works in both command-line (ideal for experienced users) and Graphical User Interface (GUI) mode (reducing the learning curve for first-time users). Both options have “crib-sheets,” user-command sequences in ASCII format that can facilitate record-and-repeat actions, especially for complex operations and plotting. Crib-sheets enhance scientific interactions, as users can move rapidly and accurately from exchanges of technical information on data processing to efficient discussions regarding data interpretation and science. SPEDAS can readily query and ingest all International Solar Terrestrial Physics (ISTP)-compatible products from the Space Physics Data Facility (SPDF), enabling access to a vast collection of historic and current mission data. The planned incorporation of Heliophysics Application Programmer’s Interface (HAPI) standards will facilitate data ingestion from distributed datasets that adhere to these standards. Although SPEDAS is currently Interactive Data Language (IDL)-based (and interfaces to Java-based tools such as Autoplot), efforts are under-way to expand it further to work with python (first as an interface tool and potentially even receiving an under-the-hood replacement). We review the SPEDAS development history, goals, and current implementation. We explain its “modes of use” with examples geared for users and outline its technical implementation and requirements with software developers in mind. We also describe SPEDAS personnel and software management, interfaces with other organizations, resources and support structure available to the community, and future development plans.
371 citations
Authors
Showing all 13486 results
Name | H-index | Papers | Citations |
---|---|---|---|
Wolfgang Wagner | 156 | 2342 | 123391 |
Helmut Sies | 133 | 670 | 78319 |
Cristina Riccardi | 129 | 1627 | 91452 |
Klaus-Robert Müller | 129 | 764 | 79391 |
Alex Zunger | 128 | 826 | 78798 |
Rolf Müller | 104 | 905 | 50027 |
Rudolf Valenta | 102 | 748 | 38349 |
Oliver G. Schmidt | 100 | 1083 | 39988 |
Kenneth N. Timmis | 97 | 365 | 34912 |
Thomas Braun | 96 | 744 | 38576 |
Ursula Keller | 92 | 934 | 33229 |
William Martin | 90 | 348 | 34353 |
Bruce T. Tsurutani | 85 | 605 | 30358 |
Michael Wink | 83 | 938 | 32658 |
Yves-Alain Barde | 83 | 168 | 35485 |