Interaction of ITER-like ICRF antenna with Tore Supra plasmas: insight from modelling

The non-linear interaction of ion cyclotron resonance frequency (ICRF) waves with the plasma edge is one of the challenges faced by high power wave heating systems in next step devices. Such interaction is often associated with parallel RF electric fields excited by spurious parallel RF currents flowing on the antenna front face I -Experimental results 1 -ICRF antenna configurations. The prototype launcher ITER-lik

Model for screening of resonant magnetic perturbations by plasma in a realistic tokamak geometry and its impact on divertor strike points

This work addresses the question of the relation between strike-point splitting and magnetic stochasticity at the edge of a poloidally diverted tokamak in the presence of externally imposed magnetic perturbations. More specifically, ad-hoc helical current sheets are introduced in order to mimic a hypothetical screening of the external resonant magnetic perturbations by the plasma. These current sheets, which suppress magnetic islands, are found to reduce the amount of splitting expected at the target, which suggests that screening effects should be observable experimentally. Multiple screening current sheets reinforce each other, i.e. less current relative to the case of only one current sheet is required to screen the perturbation.Comment: Accepted in the Proceedings of the 19th International Conference on Plasma Surface Interactions, to be published in Journal of Nuclear Materials. Version 2: minor formatting and text improvements, more results mentioned in the conclusion and abstrac

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

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

Synthesis of dialkoxydiphenylsilanes via the rhodium-catalyzed hydrosilylation of aldehydes

International audienceThe commercially available rhodium(I) complex [RhCl(CO)2]2 (1) was shown to be an effective catalyst for the reduction of carbonyls with organosilanes under mild conditions. This study focusses on the hydrosilylation of aldehydes with diphenylsilane leading to the isolation of a series of dialkoxydiphenylsilanes with low catalytic loading of complex 1. © 2019 Elsevier Lt

The synthesis of an isopropyl substituted 1,4,7-triazacyclononane via an in situ sequential macrocyclisation method

Using L-valine methyl ester hydrochloride as starting material, the synthesis of ( 2S)- 2- isopropyl- 1,4,7- trimethyl-1,4,7- triazacyclononane is described. Various standard Richman - Atkins cyclisation methods gave only poor yields in the key macrocyclisation step. Efficient macrocyclisation yields were, however, realised when an in situ sequential cyclisation method was developed

The synthesis of chiral annulet 1,4,7-triazacyclononanes

Novel and flexible routes for the synthesis of chiral ring annulet 2,6-disubstituted 1,4,7-trimethyl-1,4,7-triazamacrocycles are described. Efficient macrocyclisations were realised provided that chiral analogues of N,N-bis-[2-(toluene-sulfonyl-amino)ethyl]-toluene-4-sulfonamide were used as the nueleophilic components. Complexes prepared, in situ, from these 2,6-disubstituted 1,4,7-timethyl-1,4,7-triazamacrocycles and manganese(II) catalysed the asymmetric epoxidation of styrene with hydrogen peroxide

Harvesting New Chiral Phosphotriesters by Phosphorylation of BINOL and Parent Bis-phenols

International audienceThe systematic study on the phosphorylation of BINOL and other bisphenols operated by chlorophosphates is described. An intriguing reactivity has been observed, which is attributable to the hydroxyl group acidity and the leaving group nucleofuge character within the phosphorylating agent used. By playing on these two parameters new chiral monophosphotriesters, symmetrical homo-BINOL bisphosphates and unsymmetrical non-homo-BINOL ones, incorporating a non-chiral side unit, were synthesized selectively and in good yields

Bifurcated, modular syntheses of chiral annulet triazacyclononanes

Three chiral 2,6-disubstituted tri-N-methyl azamacrocycles have been prepared by modular methods. These macrocycles were accessed from three chiral 1,4,7-triazaheptanes intermediates that were prepared by two independent routes. The first of these routes involved the benzylamine opening of chiral tosyl aziridines followed by debenzylation but was problematic on solubility grounds. A second, more effective, route was developed which avoided debenzylation by using ammonia in the nucleophilic opening of chiral tosyl aziridines