71 research outputs found
Electron Bernstein waves emission in the TJ-II Stellarator
Taking advantage of the electron Bernstein waves heating (EBWH) system of the
TJ-II stellarator, an electron Bernstein emission (EBE) diagnostic was
installed. Its purpose is to investigate the B-X-O radiation properties in the
zone where optimum theoretical EBW coupling is predicted. An internal movable
mirror shared by both systems allows us to collect the EBE radiation along the
same line of sight that is used for EBW heating. The theoretical EBE has been
calculated for different orientations of the internal mirror using the TRUBA
code as ray tracer. A comparison with experimental data obtained in NBI
discharges is carried out. The results provide a valuable information regarding
the experimental O-X mode conversion window expected in the EBW heating
experiments. Furthermore, the characterization of the radiation polarization
shows evidence of the underlying B-X-O conversion process.Comment: 21 pages, 14 figure
Study of the neoclassical radial electric field of the TJ-II flexible heliac
Calculations of the monoenergetic radial diffusion coefficients are presented
for several configurations of the TJ-II stellarator usually explored in
operation. The neoclassical radial fluxes and the ambipolar electric field for
the standard configuration are then studied for three different collisionality
regimes, obtaining precise results in all cases
Extension and its characteristics of ECRH plasma in the LHD
One of the main objectives of the LHD is to extend the plasma confinement
database for helical systems and to demonstrate such extended plasma
confinement properties to be sustained in steady state. Among the various
plasma parameter regimes, the study of confinement properties in the
collisionless regime is of particular importance. Electron cyclotron resonance
heating (ECRH) has been extensively used for these confinement studies of the
LHD plasma from the initial operation. The system optimizations including the
modification of the transmission and antenna system are performed with the
special emphasis on the local heating properties. As the result, central
electron temperature of more than 10 keV with the electron density of 0.6 x
10 m is achieved near the magnetic axis. The electron temperature
profile is characterized by a steep gradient similar to those of an internal
transport barrier observed in tokamaks and stellarators. 168 GHz ECRH system
demonstrated efficient heating at over the density more than 1.0 x 10
m. CW ECRH system is successfully operated to sustain 756 s discharge.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004,
Nice (France
Calculation of the bootstrap current profile for the TJ-II stellarator
Calculations of the bootstrap current for the TJ-II stellarator are
presented. DKES and NEO-MC codes are employed; the latter has allowed, for the
first time, the precise computation of the bootstrap transport coefficient in
the long mean free path regime of this device. The low error bars allow a
precise convolution of the monoenergetic coefficients, which is confirmed by
error analysis. The radial profile of the bootstrap current is presented for
the first time for the 100_44_64 configuration of TJ-II for three different
collisionality regimes. The bootstrap coefficient is then compared to that of
other configurations of TJ-II regularly operated. The results show qualitative
agreement with toroidal current measurements; precise comparison with real
discharges is ongoing
SEVA 4.0: an update of the Standard European Vector Architecture database for advanced analysis and programming of bacterial phenotypes
10 Pág.The SEVA platform (https://seva-plasmids.com) was launched one decade ago, both as a database (DB) and as a physical repository of plasmid vectors for genetic analysis and engineering of Gram-negative bacteria with a structure and nomenclature that follows a strict, fixed architecture of functional DNA segments. While the current update keeps the basic features of earlier versions, the platform has been upgraded not only with many more ready-to-use plasmids but also with features that expand the range of target species, harmonize DNA assembly methods and enable new applications. In particular, SEVA 4.0 includes (i) a sub-collection of plasmids for easing the composition of multiple DNA segments with MoClo/Golden Gate technology, (ii) vectors for Gram-positive bacteria and yeast and [iii] off-the-shelf constructs with built-in functionalities. A growing collection of plasmids that capture part of the standard-but not its entirety-has been compiled also into the DB and repository as a separate corpus (SEVAsib) because of its value as a resource for constructing and deploying phenotypes of interest. Maintenance and curation of the DB were accompanied by dedicated diffusion and communication channels that make the SEVA platform a popular resource for genetic analyses, genome editing and bioengineering of a large number of microorganisms.The SEVA repository has been developed and maintained with funds of the SYCOLIM [ERA-COBIOTECH 2018-PCI2019-111859-2] Project of the Spanish Ministry of Science and Innovation, SYNBIO4FLAV [H2020-NMBP-TR-IND/H2020-NMBP-BIO-2018-814650]; MIX-UP [MIX-UP H2020-BIO-CN-2019-870294] Contracts of the European Union; BIOSINT-CM [Y2020/TCS-6555] Project of the Comunidad de Madrid-European Structural and Investment Funds (FSE, FECER); P.I.N. acknowledges financial support by the Novo Nordisk Foundation [NNF20CC0035580, TARGET (NNF21OC0067996]; European Union's Horizon 2020 Research and Innovation Programme [814418 (SinFonia)]; M.H.H.N. acknowledges funding by the Novo Nordisk Foundation [NNF20CC0035580]; P.D. was funded by Czech Science Foundation Project 22-12505S; A.G.M. was supported by the Grants BioSinT-CM [Y2020/TCS-6555]; CONTEXT (Atracción de Talento Program) [2019-T1/BIO-14053] Projects of the Comunidad de Madrid, MULTI-SYSBIO [PID2020-117205GA-I00]; Severo Ochoa Program for Centres of Excellence in R&D [CEX2020-000999-S] funded by MCIN/AEI/10.13039/501100011033 and the ECCO (ERC-2021-COG-101044360) Contract of the EU. Funding for open access charge: European Commission Grant SYNBIO4FLAV [H2020-NMBP-TR-IND/H2020-NMBP-BIO-2018-814650].With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2020‐000999‐S)
.Peer reviewe
Latest physics results of TJ-II flexible heliac
This paper is devoted to the presentation of the most relevant recent Physics results obtained in the TJ-II flexible heliac. Firstly ECRH modulation and plasma breakdown studies are summarised; then the particle control techniques used to obtain reproducible discharges with density under control are presented. Transport studies show internal heat transport barriers that reduce heat conductivity to neoclassical values, and ELM-like transport events, similar to those observed in tokamaks and in other stellarators before and during H mode transition. Evidence of ExB sheared has been observed both in the proximity of rational surfaces. Finally, a high resolution Thomsom Scattering system has shown Te and ne profile structures
Perturbative transport experiments on TJ-II Flexible Heliac
Transport properties of TJ-II are explored performing perturbative experiments and taking advantage of TJ-II flexibility. Rotational transform can be varied in a wide range, which allows one to introduce low order rationals and to study their effect on transport. On the other hand, confinement properties can be studied at very different rotational transform values and for different values of magnetic shear: Experiments on influence of the magnetic shear on confinement are reported. In these cases a Ohmic current has been induced in TJ-II plasma to modify magnetic shear and to evaluate itsd effect on confinement, showing that negative shear improves the confinement. Heat transport is also reduced by locating a low order rational near the power deposition profile. Plasma potential profiles have been recently measured in some configurations up to the plasma core with the Heavy Ion Beam Probe (HIBP) diagnostic and the electric field values measured in low-density plasmas are consistent with neoclassical calculations near the plasma core. Plasma edge turbulent transport has been studied in configurations that are marginally stable due to decreased magnetic well. Results show a dynamical coupling between gradients and turbulent transport. Finally, cold pulse propagation has been studied showing ballistic non diffusive propagation
Treasure Act 1996 Review consultation paper
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