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  • EDP Sciences  (6)
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  • EDP Sciences  (6)
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  • 1
    Online Resource
    Online Resource
    FRIPON: a worldwide network to track incoming meteoroids
    EDP Sciences ; 2020
    In:  Astronomy & Astrophysics Vol. 644 ( 2020-12), p. A53-
    Details
    In: Astronomy & Astrophysics, EDP Sciences, Vol. 644 ( 2020-12), p. A53-
    Abstract: Context. Until recently, camera networks designed for monitoring fireballs worldwide were not fully automated, implying that in case of a meteorite fall, the recovery campaign was rarely immediate. This was an important limiting factor as the most fragile – hence precious – meteorites must be recovered rapidly to avoid their alteration. Aims. The Fireball Recovery and InterPlanetary Observation Network (FRIPON) scientific project was designed to overcome this limitation. This network comprises a fully automated camera and radio network deployed over a significant fraction of western Europe and a small fraction of Canada. As of today, it consists of 150 cameras and 25 European radio receivers and covers an area of about 1.5 × 10 6 km 2 . Methods. The FRIPON network, fully operational since 2018, has been monitoring meteoroid entries since 2016, thereby allowing the characterization of their dynamical and physical properties. In addition, the level of automation of the network makes it possible to trigger a meteorite recovery campaign only a few hours after it reaches the surface of the Earth. Recovery campaigns are only organized for meteorites with final masses estimated of at least 500 g, which is about one event per year in France. No recovery campaign is organized in the case of smaller final masses on the order of 50 to 100 g, which happens about three times a year; instead, the information is delivered to the local media so that it can reach the inhabitants living in the vicinity of the fall. Results. Nearly 4000 meteoroids have been detected so far and characterized by FRIPON. The distribution of their orbits appears to be bimodal, with a cometary population and a main belt population. Sporadic meteors amount to about 55% of all meteors. A first estimate of the absolute meteoroid flux (mag 〈 –5; meteoroid size ≥~1 cm) amounts to 1250/yr/10 6 km 2 . This value is compatible with previous estimates. Finally, the first meteorite was recovered in Italy (Cavezzo, January 2020) thanks to the PRISMA network, a component of the FRIPON science project.
    Type of Medium: Online Resource
    ISSN: 0004-6361 , 1432-0746
    URL: Article
    DOI: 10.1051/0004-6361/202038649
    RVK:
    UA 1000
    RVK:
    US 1090
    Language: English
    Publisher: EDP Sciences
    Publication Date: 2020
    detail.hit.zdb_id: 1458466-9
    SSG: 16,12
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  • 2
    Online Resource
    Online Resource
    Refined physical parameters for Chariklo’s body and rings from stellar occultations observed between 2013 and 2020
    EDP Sciences ; 2021
    In:  Astronomy & Astrophysics Vol. 652 ( 2021-8), p. A141-
    Details
    In: Astronomy & Astrophysics, EDP Sciences, Vol. 652 ( 2021-8), p. A141-
    Abstract: Context. The Centaur (10199) Chariklo has the first ring system discovered around a small object. It was first observed using stellar occultation in 2013. Stellar occultations allow sizes and shapes to be determined with kilometre accuracy, and provide the characteristics of the occulting object and its vicinity. Aims. Using stellar occultations observed between 2017 and 2020, our aim is to constrain the physical parameters of Chariklo and its rings. We also determine the structure of the rings, and obtain precise astrometrical positions of Chariklo. Methods. We predicted and organised several observational campaigns of stellar occultations by Chariklo. Occultation light curves were measured from the datasets, from which ingress and egress times, and the ring widths and opacity values were obtained. These measurements, combined with results from previous works, allow us to obtain significant constraints on Chariklo’s shape and ring structure. Results. We characterise Chariklo’s ring system (C1R and C2R), and obtain radii and pole orientations that are consistent with, but more accurate than, results from previous occultations. We confirm the detection of W-shaped structures within C1R and an evident variation in radial width. The observed width ranges between 4.8 and 9.1 km with a mean value of 6.5 km. One dual observation (visible and red) does not reveal any differences in the C1R opacity profiles, indicating a ring particle size larger than a few microns. The C1R ring eccentricity is found to be smaller than 0.022 (3 σ ), and its width variations may indicate an eccentricity higher than ~0.005. We fit a tri-axial shape to Chariklo’s detections over 11 occultations, and determine that Chariklo is consistent with an ellipsoid with semi-axes of 143.8 −1.5 +1.4 , 135.2 −2.8 +1.4 , and 99.1 −2.7 +5.4 km. Ultimately, we provided seven astrometric positions at a milliarcsecond accuracy level, based on Gaia EDR3, and use it to improve Chariklo’s ephemeris.
    Type of Medium: Online Resource
    ISSN: 0004-6361 , 1432-0746
    URL: Article
    DOI: 10.1051/0004-6361/202141543
    RVK:
    UA 1000
    RVK:
    US 1090
    Language: English
    Publisher: EDP Sciences
    Publication Date: 2021
    detail.hit.zdb_id: 1458466-9
    SSG: 16,12
    Location Call Number Limitation Availability
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    Online Resource
  • 3
    Online Resource
    Online Resource
    Possible interpretation of the precession of comet 67P/Churyumov-Gerasimenko
    EDP Sciences ; 2016
    In:  Astronomy & Astrophysics Vol. 590 ( 2016-6), p. A46-
    Details
    In: Astronomy & Astrophysics, EDP Sciences, Vol. 590 ( 2016-6), p. A46-
    Type of Medium: Online Resource
    ISSN: 0004-6361 , 1432-0746
    URL: Article
    DOI: 10.1051/0004-6361/201528029
    RVK:
    UA 1000
    RVK:
    US 1090
    Language: English
    Publisher: EDP Sciences
    Publication Date: 2016
    detail.hit.zdb_id: 1458466-9
    SSG: 16,12
    Location Call Number Limitation Availability
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    Online Resource
  • 4
    Online Resource
    Online Resource
    Progress in ITER ECE Diagnostic Design and Integration
    EDP Sciences ; 2019
    In:  EPJ Web of Conferences Vol. 203 ( 2019), p. 03003-
    Details
    In: EPJ Web of Conferences, EDP Sciences, Vol. 203 ( 2019), p. 03003-
    Abstract: The ITER Electron Cyclotron Emission (ECE) diagnostic is progressing towards its Preliminary Design Review (PDR). In parallel, the diagnostic integration in the Equatorial Port is ongoing. Port Integration has to address the structural integrity to withstand various loads, maintenance and the safety aspects of ECE diagnostic. The ITER ECE system includes radial and oblique lines-of-sight. Recently, a successful peer-review of the in-port plug Hot Calibration Source has taken place and its performance and integration feasibility has been demonstrated. Four 45-meter long low-loss transmission lines are designed to transmit mm-wave power in the frequency range of 70- 1000 GHz in both X- and O-mode polarization from the port plug to the ECE instrumentation room in the diagnostic building. Prototype transmission lines are being tested [1]. A prototype polarizing Martin-Puplett type Fourier Transform Spectrometer (FTS) operating in the fr equency range 70-1000 GHz, has a fast scanning mechanism and a cryo-cooled dual-channel THz detector system. Its performance has been tested as per ITER requirements. Assessment of the instrumentation and control requirements, functional and non-functional requirements, operation procedures, plant automation are ongoing for the PDR. The current status of the diagnostic, together with integration activities, is presented.
    Type of Medium: Online Resource
    ISSN: 2100-014X
    URL: Article
    DOI: 10.1051/epjconf/201920303003
    Language: English
    Publisher: EDP Sciences
    Publication Date: 2019
    detail.hit.zdb_id: 2595425-8
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  • 5
    Online Resource
    Online Resource
    5p-3d AND 4f-3d EMISSIONS IN La, Ba AND Cs HALIDES
    EDP Sciences ; 1987
    In:  Le Journal de Physique Colloques Vol. 48, No. C9 ( 1987-12), p. C8-649-C8-652
    Details
    In: Le Journal de Physique Colloques, EDP Sciences, Vol. 48, No. C9 ( 1987-12), p. C8-649-C8-652
    Type of Medium: Online Resource
    ISSN: 0449-1947
    URL: Article
    DOI: 10.1051/jphyscol:19879111
    Language: English
    Publisher: EDP Sciences
    Publication Date: 1987
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  • 6
    Online Resource
    Online Resource
    MISTRAL campaign in support of W7-X long pulse operation
    EDP Sciences ; 2023
    In:  EPJ Web of Conferences Vol. 277 ( 2023), p. 04009-
    Details
    In: EPJ Web of Conferences, EDP Sciences, Vol. 277 ( 2023), p. 04009-
    Abstract: Following two initial campaigns [1], Stellarator Wendelstein 7-X (W7-X) has now completed the construction phase by installation of active cooling of all plasma facing components. The machine is presently commissioned for the next campaign (OP2) aiming at 1 GJ per pulse, e.g. 100 s at 10 MW, eventually aiming at 18 GJ, e.g. 1800 s at 10 MW. The key heating system is the Electron Cyclotron Resonance Heating (ECRH) system, consisting of 10 gyrotrons with power per gyrotron ranging from 0.6 MW up to 1.0 MW at 140 GHz. A phased upgrade of the installation is in progress with the addition of 2 gyrotrons and the development of 1.5 MW and 2.0 MW gyrotrons, such that at the end of the upgrade 4 gyrotrons will be available in each power class of 1.0, 1.5 and 2.0 MW [2] . The increased ECRH power, combined with O2 and X3 heating schemes at high densities, will lead to increased microwave stray radiation. This is non-absorbed microwave power that diffuses inside the vessel and is incident on all in-vessel components including vacuum windows and attached diagnostic systems. A fraction of the stray radiation is absorbed by resistive or dielectric losses of these components, leading to thermal loads that scale with stray radiation levels and pulse length. At W7-X a high power microwave stray radiation launch facility ’MISTRAL’ is available that is used to qualify invessel components for use at specified microwave surface power densities [Wm −2 ]. This paper reports on MISTRAL campaigns in 2020 2021 for testing of stray radiation loads during OP2 in W7-X, as well as on an EUROfusion program assessing stray radiation loads on ITER components. A dedicated, absolutely calibrated, caloric load was developed for the campaign to obtain measurement of stray radiation power levels as well as to conveniently expose samples. Amongst other we report on shielding concepts using metal enclosures combined with microwave absorbing coatings and dielectric heating of vacuum windows.
    Type of Medium: Online Resource
    ISSN: 2100-014X
    URL: Article
    DOI: 10.1051/epjconf/202327704009
    Language: English
    Publisher: EDP Sciences
    Publication Date: 2023
    detail.hit.zdb_id: 2595425-8
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