Comment on "Is Dark Matter with Long-Range Interactions a Solution to All Small-Scale Problems of \Lambda CDM Cosmology?"

In Phys. Rev. Lett. 109 (2012) 231301, van den Aarssen et al. attempt to solve all the small-scale structure problems in the cold-dark-matter scenario by introducing interaction between the dark-matter particle and an MeV-mass vector boson. In addition, the latter is coupled to ordinary neutrinos, and the neutrino-vector boson coupling constant 10^{-5} < g_nu < 0.1 is required for that purpose. We show that this dark-matter scenario is subject to restrictive constraints from Big Bang Nucleosynthesis.Comment: 2 pages, 1 figur

Improvements to the Sink Strength Theory Used in Multi-Scale Rate Equation Simulations of Defects in Solids

The application of mean-field rate theory equations have proven to be a versatile method in simulating defect dynamics and temporal changes in the microstructure of materials. The reliability and usefulness of the method, however, depends critically on the defect interaction parameters used. In this study, we show that the main interaction parameter, the sink strength, intrinsically depends on the detrapping, or the dissociation process itself. We present a theory on how to determine the appropriate sink strengths. The correct sink strength required for a detrapping defect, is considerably larger than the values commonly used, and thus should not be neglected.Peer reviewe

On the role of finite grid extent in SOLPS-ITER edge plasma simulations for JET H-mode discharges with metallic wall

Peer reviewe

First observation of the depolarization of Thomson scattering radiation by a fusion plasma

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Neutron emission spectroscopy of D plasmas at JET with a compact liquid scintillating neutron spectrometer

Peer reviewe

Overview of the JET preparation for deuterium-tritium operation with the ITER like-wall

For the past several years, the JET scientific programme (Pamela et al 2007 Fusion Eng. Des. 82 590) has been engaged in a multi-campaign effort, including experiments in D, H and T, leading up to 2020 and the first experiments with 50%/50% D-T mixtures since 1997 and the first ever D-T plasmas with the ITER mix of plasma-facing component materials. For this purpose, a concerted physics and technology programme was launched with a view to prepare the D-T campaign (DTE2). This paper addresses the key elements developed by the JET programme directly contributing to the D-T preparation. This intense preparation includes the review of the physics basis for the D-T operational scenarios, including the fusion power predictions through first principle and integrated modelling, and the impact of isotopes in the operation and physics of D-T plasmas (thermal and particle transport, high confinement mode (H-mode) access, Be and W erosion, fuel recovery, etc). This effort also requires improving several aspects of plasma operation for DTE2, such as real time control schemes, heat load control, disruption avoidance and a mitigation system (including the installation of a new shattered pellet injector), novel ion cyclotron resonance heating schemes (such as the three-ions scheme), new diagnostics (neutron camera and spectrometer, active Alfven eigenmode antennas, neutral gauges, radiation hard imaging systems...) and the calibration of the JET neutron diagnostics at 14 MeV for accurate fusion power measurement. The active preparation of JET for the 2020 D-T campaign provides an incomparable source of information and a basis for the future D-T operation of ITER, and it is also foreseen that a large number of key physics issues will be addressed in support of burning plasmas.Peer reviewe

Real-time implementation with FPGA-based DAQ system of a probabilistic disruption predictor from scratch

Peer reviewe

Adaptive predictors based on probabilistic SVM for real time disruption mitigation on JET

Peer reviewe

Assessment of the baseline scenario at q(95) similar to 3 for ITER

Peer reviewe

Effect of the relative shift between the electron density and temperature pedestal position on the pedestal stability in JET-ILW and comparison with JET-C

Peer reviewe