Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

Violence and publicity: constructions of political responsibility after 9/11

Focussing upon recent political philosophical reflections on the War on Terror, this paper asks whether violence can be understood without undermining the empirical and normative potential of public action to curtail it. Explanations of political violence are often either dismissed as mere exoneration, or end up reducing all forms of power to violence. Negotiating a path between these poles requires developing a double sense of responsibility that affirms that while violence can be comprehended as a rational phenomenon this does not in principle undermine the potential of public action to democratize violence. Theoretical approaches that ontologize violence as an ineradicable feature of 'the political' are criticized for leaving little space for thinking about the possibility of legitimate public action in curtailing political violence. The public dimensions of the relationships between justification, legitimacy and political violence are considered by relating contemporary left-liberal arguments about terrorism and legitimate violence to recent feminist conceptualizations of the practice of taking responsibility

Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

Influence and selection processes in weapon carrying during adolescence: the roles of status, aggression, and vulnerability.

The role of peers in weapon carrying (guns, knives, and other weapons) inside and outside the school was examined in this study. Data stem from a longitudinal study of a high-risk sample of male students (7th to 10th grade; N = 167) from predominantly Hispanic low-socioeconomic- status schools in the United States. Longitudinal social-network models were used to test whether similarity in weapon carrying among friends results from peer influence or selection. From a goalframing approach, we argue that weapon carrying might function as a status symbol in friendship networks and, consequently, be subject to peer influence. The findings indicate that weapon carrying is indeed a result of peer influence. The role of status effects was supported by findings that weapon carrying increased the number of friendship nominations received by peers and reduced the number of given nominations. In addition, peer-reported aggressiveness predicted weapon carrying 1 year later. These findings suggest that adolescent weapon carrying emerges from a complex interplay between the attraction of weapon carriers for affiliation, peer influence in friendship networks, and individual aggression.

Impact of nitrogen seeding on confinement and power load control of a high-triangularity JET ELMy H-mode plasma with a metal wall

This paper reports the impact on confinement and power load of the high-shape 2.5MA ELMy H-mode scenario at JET of a change from an all carbon plasma facing components to an all metal wall. In preparation to this change, systematic studies of power load reduction and impact on confinement as a result of fuelling in combination with nitrogen seeding were carried out in JET-C and are compared to their counterpart in JET with a metallic wall. An unexpected and significant change is reported on the decrease of the pedestal confinement but is partially recovered with the injection of nitrogen.Comment: 30 pages, 16 figure