Seguendo Grothendieck

Abstract

Impact of fast ions on density peaking in JET: fluid and gyrokinetic modeling

The effect of fast ions on turbulent particle transport, driven by ion temperature gradient (ITG)/trapped electron mode turbulence, is studied. Two neutral beam injection (NBI) heated JET discharges in different regimes are analyzed at the radial position rho(t) = 0.6, one of them an L-mode and the other one an H-mode discharge. Results obtained from the computationally efficient fluid model EDWM and the gyro-fluid model TGLF are compared to linear and nonlinear gyrokinetic GENE simulations as well as the experimentally obtained density peaking. In these models, the fast ions are treated as a dynamic species with a Maxwellian background distribution. The dependence of the zero particle flux density gradient (peaking factor) on fast ion density, temperature and corresponding gradients, is investigated. The simulations show that the inclusion of a fast ion species has a stabilizing influence on the ITG mode and reduces the peaking of the main ion and electron density profiles in the absence of sources. The models mostly reproduce the experimentally obtained density peaking for the L-mode discharge whereas the H-mode density peaking is significantly underpredicted, indicating the importance of the NBI particle source for the H-mode density profile

JARDINES DEL HOTEL TAORO [Material gráfico]

* POSITIVO DE PLACA ORIGINAL. ADQUIRIDA POR EL COLECCIONISTA EN TENERIFE.FOTO VDE VISTA GENERAL DE LOS JARDINES DEL HOTEL TAOROCopia digital. Madrid : Ministerio de Educación, Cultura y Deporte. Subdirección General de Coordinación Bibliotecaria, 201

Listeria spp. and L. monocytogenes in raw goat`s milk

Objetivo. Detectar Listeria spp. y Listeria monocytogenes en leches crudas de cabras, provenientes del corregimiento de la Garita, Norte de Santander. Materiales y métodos. Se tomaron 90 muestras de leche cruda de cabra, mediante muestreo estratificado, en un período de 4 meses; durante el muestreo se tomó la temperatura de las leches. Para el aislamiento de L. monocytogenes se utilizó la técnica sugerida por el INVIMA y se confirmó la especie por PCR. Resultados. Se encontraron ocho productores de leches de cabra en esta zona, ninguno refrigera, ni pasteuriza la leche. Se encontró una ocurrencia de 3% de L. monocytogenes y 15% de otras especies. Se demostró que la leches obtenidas en esta zona contienen este patógeno que puede llegar a causar Listeriosis en los grupos de riesgo como niños menores de 5 años, mujeres en etapa de gestación, adultos mayores y pacientes inmunocomprometidos. Conclusiones. Se demostró la circulación de este patógeno en la leche de cabra y al ser un producto que se consume directamente por las personas pone en riesgo su salud

First results from recent JET experiments in Hydrogen and Hydrogen-Deuterium plasmas

The hydrogen campaign completed at JET in 2016 has demonstrated isotope ratio control in JET-ILW using gas puffing and pellets for fuelling, Neutral Beam Injection alone or in combination, with D/H spectroscopy as a diagnostic. The plasma properties such as confinement, L-H threshold, density limit depend on the isotope composition. The L-H transition power increases with the hydrogen concentration with a wide plateau in the range 0.2<nH/(nD+nH)<0.8. Energy confinement is significantly lower in hydrogen than in comparable deuterium ELMy H-mode plasmas, suggesting an isotope mass scaling that is stronger than in IPB98(y,2). In L-mode, the isotope dependence of confinement is weaker. The H-mode density limit in hydrogen is up to 35% lower than in heuterium, whilst it is found to be higher in L-mode. The lower ion mass leads to reduced tungsten sputtering in hydrogen plasmas. During the campaign, the nD/(nD+nH) ratio dropped to ~1% in only a few discharges after the last deliberate introduction of deuterium, although it was seen to rise again to ~2% with several seconds of exposure of the divertor tiles to ~10MW of auxiliary heating. Several ICRH scenarios were also tested in hydrogen plasmas