Lawson criterion for ignition exceeded in an inertial fusion experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion

Caracteristicas bioclimaticas de las malezas del cinturon verde de cordoba: parte I - Polygonum aviculare "sanguinaria" Bioclimatic characteristic of weeds in the city Cordoba's green belt: part I - Polygonum aviculare

<abstract language="por">Na região fruti-ortícula do cinturião verde da cidade de Córdoba, Argentina, ocorre com frequência nos períodos de inverno e primavera o aparecimento de Polygomun aviculare. O objetivo do presente trabalho foi o de conhecer a fenologia desta espécie e as necessidades bioclimáticas de cada uma das etapas do seu ciclo de vida. Para estas análises conduziu-se um ensaio em uma propriedade do cinturião verde, na região Nordeste de Córdoba, durante os anos de 1988, 1989 e 1990. Determinrou-se as fases e subperíodos do ciclo evolutivo da espécie e parâmetros como altura e densidade de plantas e dados meteorológicos. O estudo permitiu estabelecer o fluxo estacional de emergência e determinar o tipo ecológico de planta daninha quanto à estação de crescimento. Os aspectos ecológicos levantados servirão de ferramentas para implementar estratégias de controle desta planta daninha.<br>"Knotweed", Polygonum aviculare is one of the most common weeds in the winter-spring period in the horticultural zone of Córdoba green belt. In order to know the phenology and climatic requirements of the species in each stage of its life cycle, an experiment was conducted in one of the green belt farms located in the NE of Córdoba outskirsts for three years (1988, 1989, 1990). Different phases and sub-periods of this life cycle, phenometric parameters (plant height and density) and meteorological observations were determined. The experiment enabled to establish the stational flow of emergency and corroborate the winterspring ecological type of the weed. These aspects of the bioecology, phenology and bioclimatology are necessary tools when implementing an integrated system of weed control