Effects of plasma turbulence on the nonlinear evolution of magnetic island in tokamak

Magnetic islands (MIs), resulting from a magnetic field reconnection, are ubiquitous structures in magnetized plasmas. In tokamak plasmas, recent researches suggested that the interaction between an MI and ambient turbulence can be important for the nonlinear MI evolution, but a lack of detailed experimental observations and analyses has prevented further understanding. Here, we provide comprehensive observations such as turbulence spreading into an MI and turbulence enhancement at the reconnection site, elucidating intricate effects of plasma turbulence on the nonlinear MI evolution

Innovative Confinement Concepts Workshop - 2002: Conference report

The Innovative Confinement Concepts Workshop, ICC2002, provided a forum for presentations and exchange of ideas on the science and status of innovative concepts in the U.S. Fusion Energy Program. The workshop, held at the University of Maryland on January 22-24, 2002, included oral presentations addressing the important science and status of the concepts, posters focussed on details of the work, a skunkworks for novel ideas, and breakout sessions preparing for the July 2002 fusion energy Snowmass meeting. This report summarizes the oral presentations. A web site (https:// wormhole.ucllnl.org/ICC2002/) has been established with the abstracts and many of the presentations, both oral and poster, from the workshop

Percepción de la experiencia de violencia doméstica en mujeres víctimas de maltrato de pareja

This study aimed to understand the perceptions that domestic violence has a group of women victims of it. To this end we conducted a qualitative study on the technique of focus groups. The research participants were 9 women victims of domestic violence between the ages of 25 and 60 years served in an ONG of Bogotá city. It was found in women with a negative perception of themselves while minimizing many of the skills they possess, and evaluating their skills as inferior to men, which have learned from their families of origin.El presente estudio tuvo como objetivo comprender las percepciones que sobre la violencia doméstica tiene un grupo de mujeres víctimas de la misma. Para tal fin, se llevó a cabo una investigación de tipo cualitativo bajo la técnica de grupos focales. Las participantes de la investigación fueron nueve mujeres víctimas de la violencia doméstica, con edades comprendidas entre los 25 y 60 años, atendidas en una ONG de la ciudad de Bogotá. Se encontró que las mujeres tienen una percepción negativa de sí mismas, aprendida desde sus familias de origen, pues minimizan muchas de sus capacidades y evalúan sus habilidades como inferiores a las de los hombres

Chapter 3: MHD stability, operational limits and disruptions

Progress in the area of MHD stability and disruptions, since the publication of the 1999 ITER Physics Basis document (1999 Nucl. Fusion 39 2137-2664), is reviewed. Recent theoretical and experimental research has made important advances in both understanding and control of MHD stability in tokamak plasmas. Sawteeth are anticipated in the ITER baseline ELMy H-mode scenario, but the tools exist to avoid or control them through localized current drive or fast ion generation. Active control of other MHD instabilities will most likely be also required in ITER. Extrapolation from existing experiments indicates that stabilization of neoclassical tearing modes by highly localized feedback-controlled current drive should be possible in ITER. Resistive wall modes are a key issue for advanced scenarios, but again, existing experiments indicate that these modes can be stabilized by a combination of plasma rotation and direct feedback control with non-axisymmetric coils. Reduction of error fields is a requirement for avoiding non-rotating magnetic island formation and for maintaining plasma rotation to help stabilize resistive wall modes. Recent experiments have shown the feasibility of reducing error fields to an acceptable level by means of non-axisymmetric coils, possibly controlled by feedback. The MHD stability limits associated with advanced scenarios are becoming well understood theoretically, and can be extended by tailoring of the pressure and current density profiles as well as by other techniques mentioned here. There have been significant advances also in the control of disruptions, most notably by injection of massive quantities of gas, leading to reduced halo current fractions and a larger fraction of the total thermal and magnetic energy dissipated by radiation. These advances in disruption control are supported by the development of means to predict impending disruption, most notably using neural networks. In addition to these advances in means to control or ameliorate the consequences of MHD instabilities, there has been significant progress in improving physics understanding and modelling. This progress has been in areas including the mechanisms governing NTM growth and seeding, in understanding the damping controlling RWM stability and in modelling RWM feedback schemes. For disruptions there has been continued progress on the instability mechanisms that underlie various classes of disruption, on the detailed modelling of halo currents and forces and in refining predictions of quench rates and disruption power loads. Overall the studies reviewed in this chapter demonstrate that MHD instabilities can be controlled, avoided or ameliorated to the extent that they should not compromise ITER operation, though they will necessarily impose a range of constraints