1,721,059 research outputs found
Design of the Local Control Coils at the equatorial gap of the RFX machine
No full textThe paper describes a method for the identification of the plasma shape in a toroidal device for the fusion experiments based on magnetic confinement. The method, developed for the RFX machine, makes use of the magnetic measurements and takes into account the electromagnetic effects of a conductive vacuum vessel and of a stabilizing shell. These effects are quite important in “fast” machines such as the RFPs of the present generatio
Electromagnetic transducers close to high temperature plasma in thermonuclear fusion experiment RFX
No full textSusceptibility of NMR instrumentation to ELF fields
No full textSeveral malfunctions and measurements errors were
observed in a NMR spectrometer operating near a magnetic
confinement fusion experiment in Padua, Italy. A detailed study
of the interference mechanism revealed that such type of
spectrometers are extremely sensitive to external varying fields, if
their frequency is in the range between 0.1 and 3 Hz. Pulsed
fusion devices emit stray fields in this range of frequencies.
Several approaches, including an active shield, were explored to
mitigate the effects of this peculiar type of interference
Ionizing radiation compatibility in the MITICA neutral beam prototype
No full textThis paper deals with an R&D activity in progress in support of the design of the ITER NBI prototype (MITICA), aimed at the identification of the most appropriate design solutions and installation guidelines to keep under control and minimize the effects of ionizing radiation on the electronic and passive components related to control, diagnostics, and electrical insulation located inside the MITICA vessel and its concrete biological shield. The method followed to approach the problem is based on three steps: estimation of expected radiation levels map, identification of electronic and passive components database for MITICA diagnostics and finally the assessment of the ionizing radiation compatibility for the identified components. The ultimate aim of this activity is the definition, on the basis of this assessment, of a list of preventive or mitigating actions (such as relocation, shielding or preventive maintenance) for the most high-risk components. (C) 2011 S. Peruzzo. Published by Elsevier B.V. All rights reserved
GUIDELINES FOR AN OPTIMAL DESIGN OF FIRST WALL COMPONENTS FOR RFP DEVICES
No full textThe RFX experimental results at the highest plasma current (about 1 MA) and for relatively long pulses (150 ms) show the presence of high power flux densities on the first wall, up to 40 MW/m2 averaged on a single tile. Detailed numerical analyses have been carried out to simulate the thermal response of a single tile. The results of sensitivity analyses give information on the radiative and convective power flux intensities and the related first wall temperature distributions. The experimental data and the results of thermal analyses give quantitative information and qualitative guidelines for the design of an optimized first wall for a RFP device
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Technology developments for ITER in-vessel equilibrium magnetic sensors
No full textThe ITER magnetic equilibrium sensors will be installed in a hostile environment characterized by severe neutron radiation and heat loads, which can cause undesired spurious signals and compromise the accuracy of the measurements obtained by time-integration. The paper deals with the construction and tests of prototype in-vessel pick-up coils, which have been developed aiming at the reduction of the adverse effects of neutron radiation by using suitable materials and by minimizing the thermal gradients. A first solution based on a winding made of a flexible ceramic-coated conductor (instead of a Mineral Insulated Cables) and “impregnated” with ceramic filler has been implemented and tested. A second solution based on coils constituted by a stack of circuits printed on a ceramic substrate sintered in one piece has also been developed and tested with positive results. The paper describes the design developments, the rationale for the test and discusses the results and the developments necessary for the production of reliable equilibrium sensors for ITER
Electromagnetic transducers close to high temperature plasma in thermonuclear fusion experiment RFX
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