Plasma Jets and Eruptions in Solar Coronal Holes: a 3D flux emergence experiment

A three-dimensional numerical experiment of the launching of a hot and fast coronal jet followed by several violent eruptions is analyzed in detail. These events are initiated through the emergence of a magnetic flux rope from the solar interior into a coronal hole. We explore the evolution of the emerging magnetically-dominated plasma dome surmounted by a current sheet and the ensuing pattern of reconnection. A hot and fast coronal jet with inverted-Y shape is produced that shows properties comparable to those frequently observed with EUV and X-Ray detectors. We analyze its 3D shape, its inhomogeneous internal structure, and its rise and decay phases, lasting for some 15-20 min each. Particular attention is devoted to the field-line connectivities and the reconnection pattern. We also study the cool and high-density volume that appears encircling the emerged dome. The decay of the jet is followed by a violent phase with a total of five eruptions. The first of them seems to follow the general pattern of tether-cutting reconnection in a sheared arcade, although modified by the field topology created by the preceding reconnection evolution. The two following eruptions take place near and above the strong field-concentrations at the surface. They show a twisted, \Omega-loop like rope expanding in height, with twist being turned into writhe, thus hinting at a kink instability (perhaps combined with a torus-instability) as the cause of the eruption. The succession of a main jet ejection and a number of violent eruptions that resemble mini-CME's and their physical properties suggest that this experiment may provide a model for the blowout jets recently proposed in the literature.Comment: Accepted for publication in The Astrophysical Journal (vol 770, June 2013

Are tornado-like magnetic structures able to support solar prominence plasma?

Recent high-resolution and high-cadence observations have surprisingly suggested that prominence barbs exhibit apparent rotating motions suggestive of a tornado-like structure. Additional evidence has been provided by Doppler measurements. The observations reveal opposite velocities for both hot and cool plasma on the two sides of a prominence barb. This motion is persistent for several hours and has been interpreted in terms of rotational motion of prominence feet. Several authors suggest that such barb motions are rotating helical structures around a vertical axis similar to tornadoes on Earth. One of the difficulties of such a proposal is how to support cool prominence plasma in almost-vertical structures against gravity. In this work we model analytically a tornado-like structure and try to determine possible mechanisms to support the prominence plasma. We have found that the Lorentz force can indeed support the barb plasma provided the magnetic structure is sufficiently twisted and/or significant poloidal flows are present.Comment: Accepted for publication in ApJ

La negociación colectiva y el diálogo social: perspectiva empresarial.

Sin resume

Para una poética del imaginario espacial en la narrativa de Roberto Bolaño

El artículo intenta poner de relieve dos configuraciones espaciales específicas vinculadas con el quehacer narrativo de Roberto Bolaño. La primera se vincula con un determinado espacio personal, construido por los signos y su acción significante, que configuran una suerte de espacio literario abismal. La segunda, que se expresa en los tramos de la textualidad, se caracteriza por una escritura derivativa y expansiva, y por una sintaxis que procede por la abundancia, la repetición sostenida y la acumulación rizomática.The article tries to emphasize in two specific spatial configurations of Roberto Bolaño's narrative. The first one relates to a particular personal space, built by the signs and his significant action, that form a sort of abysmal literary space. The second one, which is expressed in the sections of textuality, is characterized by a derivative and expansive writing and for a syntax that by abundance proceeds the sustained repetition and the rhizomatic accumulation

BOLAÑO 60/10 : Nuevas lecturas

Presentación del númer

Análisis crítico de los informes de evaluación de la amenaza del crimen organizado en la Unión Europea (Oganised Crime Threat Assessment, OCTA)

Tradicionalmente, la orientación reactiva de los cuerpos de seguridad ha hecho que prevalezca un modelo de orientación estratégica basado en la capacidad de respuesta ante hechos consumados o que se encuentran en proceso de ejecución. En la actualidad, diversos factores están condicionando los esfuerzos policiales hacia un modelo de estrategia prospectiva