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According to recent DIII-D experiments (Logan et al 2024 Nucl. Fusion 64 014003), injecting edge localized electron cyclotron current drive (ECCD) in the counter-plasma-current (counter- I _p ) direction reduces the n = 3 resonant magnetic perturbation (RMP) current threshold for edge-localized mode (ELM) suppression, while co- I _p ECCD during the suppressed ELM phase causes a back transition to ELMing. This paper presents nonlinear two-fluid simulations on the ECCD manipulation of edge magnetic islands induced by RMP using the TM1 code. In the presence of a magnetic island chain at the pedestal-top, co- I _p ECCD is found to decrease the island width and restore the initially degraded pedestal pressure when its radial deposition location is close to the rational surface of the island. With a sufficiently strong co- I _p ECCD current, the RMP-driven magnetic island can be healed, and the pedestal pressure fully recovers to its initial ELMing state. On the contrary, counter- I _p ECCD is found to increase the island width and further reduce the pedestal pressure to levels significantly below the peeling-ballooning-mode limited height, leading to even stationary ELM suppression. These simulations align with the results from DIII-D experiments. However, when multiple magnetic island chains are present at the pedestal-top, the ECCD current experiences substantial broadening, and its effects on the island width and pedestal pressure become negligible. Further simulations reveal that counter- I _p ECCD enhances RMP penetration by lowering the penetration threshold, with the degree of reduction proportional to the amplitude of ECCD current. For the ∼1 MW ECCD in DIII-D, the predicted decrease in the RMP penetration threshold for ELM suppression is approximately 20%, consistent with experimental observations. These simulations indicate that edge-localized ECCD can be used to either facilitate RMP-driven ELM suppression or optimize the confinement degradation.

Sawtooth crashes are observed during ECCD experiments at the superconducting optimized stellarator Wendelstein 7-X. The study and the characterization are necessary in order to understand under which condition ECCD can be driven without posing a risk to experimental operations. The development of automatic tools is crucial to speed up the analysis of extensive datasets. In this work, we report on the first attempt of using a data-driven approach to automatically characterize the sawtooth crashes. Cluster algorithms are applied to the dataset, confirming the existence of two distinct types of crashes. This approach allows to study the two groups separately and underlines the different plasma parameters that influence the sawtooth crash parameters, for instance crash amplitude and period.

The Early Childhood Care and Development (ECCD) and Education in Sri Lanka have been considered vital for human development (UNICEF, 2007 cited in Gallardo, 2009). Yet, there is less attention paid to the scrutinised formulation of policies related to this aspect in Sri Lanka. Furthermore, child-related studies conducted in Sri Lanka are limited. This paper aims to contribute to this necessity by conducting a critical evaluation regarding the responsibility of the formulation of ECCD and education policies in Sri Lanka. A qualitative research design was used for this study. Thirteen policy documents related to ECCD and education were critically analysed and interviews were conducted with responsible informants of ECCD and education in order to gather data. The findings exhibited that there was no single designated authority that is responsible for the formulation of policies related to ECCD and education in Sri Lanka. Furthermore, it was noted that the responsibility of ECCD and education-related policy formulation constantly shifted from one authority to another. In addition, it was noted that the responsibility regarding the formulation of policies for different aspects of ECCD and education were delegated to different parties. Lack of coordination among these diverse parities had resulted in no clear-cut policies for any of the aspects of ECCD and education. Furthermore, lack of supervision and monitoring had resulted in the non-implementation of the prevalent ECCD and education policies in Sri Lanka. Hence, the requirement for stern and stable ECCD policy formulating and monitoring agents is highlighted in the present study.

The impact of electron cyclotron current drive (ECCD)-driven current on toroidicity-induced Alfvén eigenmodes (TAEs) in experiments on the AUG tokamak is investigated numerically. The dynamical evolution of the plasma profiles and equilibria are modelled with European transport solver, while ion cyclotron resonance heating-accelerated H-minority ions exciting TAEs are assessed with the PION code. TAEs, their drive and damping are computed with the codes CASTOR and CASTOR-K. In the set of discharges analysed, two groups of TAEs are observed, differing in frequency and radial location. Experimental observations show that when counter-ECCD is applied the higher frequency group of approximately 150 kHz is suppressed, while the lower frequency modes of 125 kHz are amplified. When co-ECCD is applied, depending on the location of the ECCD current deposition layer, both groups of TAE can be suppressed. Numerical calculations of energetic particle drive and thermal plasma damping show that neither one effect could explain the variety of the experimental observations. The fine balance between the drive, sensitive to the TAE position, and the radiative and continuum damping effects could only explain the experiment if the effects are considered all together.

• A rapid inter-shot analysis method of current profile is proposed. • The simulation results are reasonably consistent with the experimental data. • Broadening current profile and even local reversed shear for advanced scenario are predicted with dedicated current drive scheme. Simulation of the current density profile is desirable in developing advanced scenarios. An efficient and fast integrated simulation code, Minute Embedded Tokamak Integrated Simulator (METIS), which features its simplified physics models, is proposed for investigating the current density profile. Despite the simplification, the simulation is reasonably consistent with the EAST experimental results. Modeling predictions indicate that a broadening current density profile or even local reversed shear can be obtained with dedicated off-axis Electron Cyclotron Current Drive (ECCD) and on-axis counter-ECCD depositions when the EC power is large enough. Results reported in this paper provide insight about how to optimize the current profile in the advanced scenario exploration on EAST with the ECCD system upgrade. [ABSTRACT FROM AUTHOR]

Rapid derivatization of chiral 1,2‐diols with dinaphthyl borinic acid (DBA) leads to a cyclic boronate, enabling the absolute stereochemical prediction via exciton‐coupled circular dichroic (ECCD) of the naphthyl groups. Aryl‐ and alkyl‐substituted 1,2‐diols derivatized with DBA yield a predictable ECCD, which is also in agreement with theoretical predictions derived from computationally minimized structures. [ABSTRACT FROM AUTHOR]

The electron cyclotron resonance heating (ECRH) system of the ASDEX Upgrade tokomak has been upgraded over the last 15 years from a 2MW, 2 s, 140 GHz system to an 8MW, 10 s, dual frequency system (105/140 GHz). The power exceeds the L/H power threshold by at least a factor of two, even for high densities, and roughly equals the installed ion cyclotron range of frequencies power. The power of both wave heating systems together (>10MW in the plasma) is about half of the available neutral beam injection (NBI) power, allowing significant variations of torque input, of the shape of the heating profile and of Qe/Qi, even at high heating power. For applications at a low magnetic field an X3-heating scheme is routinely in use. Such a scenario is now also forseen for ITER to study the first H-modes at one third of the full field. This versatile system allows one to address important issues fundamental to a fusion reactor: H-mode operation with dominant electron heating, accessing low collisionalities in full metal devices (also related to suppression of edge localized modes with resonant magnetic perturbations), influence of Te/Ti and rotational shear on transport, and dependence of impurity accumulation on heating profiles. Experiments on all these subjects have been carried out over the last few years and will be presented in this contribution. The adjustable localized current drive capability of ECRH allows dedicated variations of the shape of the q-profile and the study of their influence on non-inductive tokamak operation (so far at q95 > 5.3). The ultimate goal of these experiments is to use the experimental findings to refine theoretical models such that they allow a reliable design of operational schemes for reactor size devices. In this respect, recent studies comparing a quasi-linear approach (TGLF) with fully non-linear modeling (GENE) of non-inductive high-beta plasmas will be reported. [ABSTRACT FROM AUTHOR]

Highlights • Measurements of magnetic island and ECCD locations are essential for NTM suppression. • Many control systems rely on diagnostics which may not be robust to neutron radiation. • Magnetic island and ECCD locations are both found with a single ECE diagnostic. • The modified Rutherford equation is used to demonstrate the effect of ECCD alignment. Abstract Accurate real-time measurements of magnetic island and electron cyclotron current drive (ECCD) locations are essential for efficient suppression of the neoclassical tearing mode (NTM). To determine these locations, many control systems rely on motional Stark effect constrained equilibria reconstruction and real-time Thomson scattering with TORBEAM current drive evaluation and therefore require time-intensive cross-calibration of at least two different diagnostics. Here we present a simpler, proof-of-concept analysis that uses only a single diagnostic (a radial array electron cyclotron emission radiometer) for the simultaneous determination of both the radial position of a magnetic island and the deposition location of ECCD. Measurements are compared with the modified Rutherford equation to demonstrate the effect of ECCD alignment on NTM suppression. [ABSTRACT FROM AUTHOR]

Abstract: The absolute stereochemistry of chiral carboxylic acids is determined as a di(1‐naphthyl)methanol ester derivative. Computational scoring of conformations favoring either P or M helicity of the naphthyl groups, capable of exciton‐coupled circular dichroic coupling, leads to a predicted stereochemistry for the derivatized carboxylic acids. [ABSTRACT FROM AUTHOR]

A diplexer to be used as a fast switching device of high power millimeter wave for an electron cyclotron current drive system has been developed. The operation frequency of the device is tunable by controlling the thermal expansion of the cavity using a precision chiller. The tunable range of the diplexer is about 225 MHz at the frequency band of 170 GHz. The temperature dependence of the resonant frequency shift in the ring resonator diplexer is −3.4 to −3.9 MHz/K, which agrees with the theoretical prediction. The switching operation is confirmed up to rf power of 260 kW, a pulse duration of 100 ms, and a frequency of 170 GHz. [ABSTRACT FROM AUTHOR]

A wideband polarizer consisting of a polarization twister and a circular polarizers have been developed for the Electron Cyclotron Current Drive system in JT-60SA at the frequencies of 110 GHz and 138 GHz. Ohmic loss of the polarization twister has been evaluated with high power test of 0.3 MW, 10 s at 110 GHz and 138 GHz. The Ohmic loss of the polarization twister made by machining process is 0.20% ∼ 0.57%. Moreover, the wideband polarization twister was tested up to 0.9 MW for 20 s at 110 GHz and 138 GHz. [ABSTRACT FROM AUTHOR]

In the present RF-driven (ECCD) steady-state plasma on QUEST ( B t = 0.25 T, R = 0.68 m, a = 0.40 m), plasma current seems to flow in the open magnetic surface outside of the closed magnetic surface in the low-field region according to plasma current fitting (PCF) method. We consider that the current in the open magnetic surface is due to orbit-driven current by high-energy particles in RF-driven plasma. So based on the analysis of current density profile based on the orbit-driven current, plasma equilibrium is to be calculated. We calculated high energy particles guiding center orbits as a contour plot of conserved variable in Hamiltonian formulation and considered particles initial position with different levels of energy and pitch angles that satisfy resonance condition. Then the profile of orbit-driven current is estimated by multiplying the particle density on the resonance surface and the velocity on the orbits. This analysis shows negative current near the magnetic axis and hollow current profile is expected even if pressure driven current is considered. Considering the hollow current profile shifted toward the low-field region, the equilibrium is fitted by J-EFIT coded by MATLAB. [ABSTRACT FROM AUTHOR]

This study aims to identify the effect of attending an enhanced-quality preschool program on students’ emergent math, emergent language and literacy, socio-personal skills and knowledge of health, hygiene, nutrition and safety. We used a quasi-experimental design with pre-post measures and two control groups, with data from a random sample of approximately 709 4–6-year-old children in 40 villages and 5 districts of Bangladesh. Controlling for demographic and baseline characteristics, we compared the outcomes of children who attended an enhanced-quality preschool with the outcomes of children who lived nearby, but were (1) not attending preschool or (2) attending a standard-quality government preschool. We found that, after controlling for baseline characteristics, initial pre-test differences that significantly favored children in enhanced-quality preschools over non-preschoolers significantly increased over time in all outcomes of interest. We did not find differences at baseline between children in the enhanced and the standard-quality preschools, but after the intervention, preschoolers in the enhanced program gained small and positive advantages over their counterparts, which were not statistically significant, possibly due to the sample size of the Government Public School group, which made us unable to detect effects sizes smaller than 0.25 standard deviations. We discuss implications, threats to validity and future research. [ABSTRACT FROM AUTHOR]

The absolute stereochemistry of cyanohydrins, derived from ketones and aldehydes, is obtained routinely, in a microscale and derivatization-free manner, upon their complexation with Zn-MAPOL, a zincated porphyrin host with a binding pocket comprised of a biphenol core. The host-guest complex leads to observable exciton-coupled circular dichroism (ECCD), the sign of which is easily correlated to the absolute stereochemistry of the bound cyanohydrin. A working model, based on the ECCD signal of cyanohydrins with known configuration, is proposed. [ABSTRACT FROM AUTHOR]

Background: The ESX-1 type VII secretion system is an important determinant of virulence in pathogenic mycobacteria, including Mycobacterium tuberculosis. This complicated molecular machine secretes folded proteins through the mycobacterial cell envelope to subvert the host immune response. Despite its important role in disease very little is known about the molecular architecture of the ESX-1 secretion system. Results: This study characterizes the structures of the soluble domains of two conserved core ESX-1 components - EccB1 and EccD1. The periplasmic domain of EccB1 consists of 4 repeat domains and a central domain, which together form a quasi 2-fold symmetrical structure. The repeat domains of EccB1 are structurally similar to a known peptidoglycan binding protein suggesting a role in anchoring the ESX-1 system within the periplasmic space. The cytoplasmic domain of EccD1 has a ubiquitin-like fold and forms a dimer with a negatively charged groove. Conclusions: These structures represent a major step towards resolving the molecular architecture of the entire ESX-1 assembly and may contribute to ESX-1 targeted tuberculosis intervention strategies. [ABSTRACT FROM AUTHOR]

• Under the parameters of the latest/final version of the CFETR concept design (R = 7.2 m, a = 2.2 m, B T = 6.5 T), the 240 GHz electron cyclotron (EC) wave of fundamental ordinary mode is the optimum candidate for the purpose of current drive. It can be launched either from equatorial launcher (EL) port, upper launcher (UL) port or top launcher (TL) port. Upper launcher of 240 GHz EC wave is the best choice. • Electron cyclotron current drive (ECCD) efficiency increases with the increasing of EC frequency in the range of 190 ∼ 250 GHz. Large toroidal incident angle α is needed for higher EC frequency to obtain an efficient CD efficiency. • Most cases of TL-ECCD significantly improve the efficiency of ECCD in the mid-radius region (ρ = 0.4 ∼ 0.6) compared with EL-ECCD, but some cases does not. It is different from the results of previous theoretical simulations on top launch ECCD, in which TL-ECCD shows significantly improve ECCD efficiency than EL launcher. More research efforts are required for effective TL-ECCD in the CFETR-like reactor-level tokamak device. RF power in the electron cyclotron (EC) frequency range is planned to be injected to the plasmas of China Fusion Engineering Test Reactor (CFETR). Numerical investigation for electron cyclotron current drive (ECCD) is performed under the parameters of the latest/final version of the CFETR concept design (R = 7.2 m, a = 2.2 m, B T = 6.5 T). The TORAY-GA ray-tracing code is used to optimize frequency and launcher ports of EC waves. It is found that both 240 GHz and 250 GHz EC waves can meet the desired current drive demand in the target radial region (ρ ≤ 0.40). The 240 GHz EC wave is the optimum candidate. It can be launched either from equatorial launcher (EL) port, upper launcher (UL) port or top launcher (TL) port. EC waves with frequency equal to or larger than 250 GHz will be suffered strong parasitic second harmonic absorption if it is launched from EL port. Except for 250 GHz wave launched from EL port, ECCD efficiency increases with the increasing of EC frequency in the range of 190 ∼ 250 GHz. The maximum CD efficiency γ CD n 20 RI ec / P in can reach 0.3 taking account for improvement of the CD efficiency about 20% enhanced by momentum conserving correction in the central radial region (ρ ≤ ∼ 0.20), either by 240 GHz EL-ECCD or 240/250 GHz UL-ECCD launching from (R i , Z i) = (8.2, 4.5) m. Large toroidal incident angle α is needed for higher EC frequency to obtain an efficient CD efficiency. Necessary and sufficient conditions for successful and effective TL-ECCD are given. Compared to UL-ECCD, TL-ECCD does not significantly improve the efficiency of ECCD in the mid-radius region (ρ = 0.4 ∼ 0.6). Most cases of TL-ECCD significantly improve the efficiency of ECCD in the mid-radius region compared with EL-ECCD, but some cases does not. It is different from the results of previous theoretical simulations, in which TL-ECCD shows significantly improve ECCD efficiency than EL launcher. These findings are of significance for design of an efficient ECCD system under the CFETR design parameters. [ABSTRACT FROM AUTHOR]

Plasma control techniques that use electron cyclotron (EC) resonance heating and current drive such as control of neoclassical tearing modes require accurate control of the deposition location of EC beams. ASDEX Upgrade has successfully implemented a real-time version of the beam-tracing code TORBEAM into its real-time diagnostic system to act as a globally available module that calculates current deposition location and its sensitivity from other real-time diagnostic measurements for all its moveable EC wave launchers. Based on a highly (100×) accelerated version of TORBEAM, the software implementation as a diagnostic process uses parallelization and achieves cycle times of 15–20 ms for determining the radial deposition location of 12 beams in the plasma. This cycle time includes data input–output overhead arising from the use of available real-time signals. The system is by design portable to other machines such as ITER. [ABSTRACT FROM AUTHOR]

Mechanical and quasi-optical design of an electron cyclotron heating/current drive launcher for JT-60SA is in progress. A full-scale mock-up of the steering structure, which enables linear and rotation motions of the first mirror of the launcher, has been fabricated for cyclic test of the bellows part. Moreover, an improved design enables easy replacement of the bellows for rotation for maintenance. Quasi-optical characteristics of the antenna mirrors have been studied to evaluate its transmission efficiency and beam focusing property. In calculation, it was found that the antenna is applicable to two frequency operation at 110 GHz and 138 GHz. It was quantitatively shown that the transmission efficiency of ∼99% (not including Ohmic loss) is obtained even with the higher order mode (LP 11 even ) fraction of 10% by optimizations of the shape of the first mirror. These results contribute to optimization/finalization of the launcher design toward fabrication of the launcher for JT-60SA. [ABSTRACT FROM AUTHOR]

At the Karlsruhe Institute of Technology (KIT), theoretical and experimental foundations for the development of future gyrotrons for fusion applications are being laid down. This includes the construction of the new Fusion Long Pulse Gyrotron Laboratory (FULGOR) test facility as well as physical design studies towards DEMO-compatible gyrotrons. Initially FULGOR will comprise of a 10 MW CW power supply, a 5 MW water cooling system (upgradeable to 10 MW), a superconducting 10 T magnet, one or two 2 MW ECRH test loads and a new control and data acquisition system for all these elements. The test facility will then be equipped to test the conventional 1 MW or coaxial 2 MW gyrotrons for DEMO, currently under design, as well as possible upgraded gyrotrons for W7-X and ITER. The design of the new high voltage DC power supply (HVDCPS) is flexible enough to handle gyrotrons with 4 MW CW output power (conceivably up to 170 GHz), but also test gyrotrons with higher frequencies (>250 GHz) which, due to physical limitations in the gyrotron design, will require less power but have more stringent demands on voltage stability. [ABSTRACT FROM AUTHOR]

A simulation is performed for feedback stabilization of neoclassical tearing mode (NTM) by electron cyclotron current drive (ECCD) for KSTAR in preparation for experiments. An integrated numerical system is constructed by coupling plasma transport, NTM stability, and heating and current drive modules and applied to a KSTAR plasma by assuming similar experimental conditions as ASDEX Upgrade to predict NTM behaviors in KSTAR. System identification is made with database produced by predictive simulations with this integrated numerical system so that three plasma response models are extracted which describe the relation between the EC poloidal launcher angle and the island width in KSTAR. Among them, the P1DI model exhibiting the highest fit accuracy is selected for designing a feedback controller based on the classical Proportional–Integral–Derivative (PID) concept. The controller is coupled with the integrated numerical system and applied to a simulation of NTM stabilization. It is observed that the controller can search and fully stabilize the mode even though the poloidal launch angle is misaligned with the island initially. [ABSTRACT FROM AUTHOR]

Highlights: [•] We developed neoclassical tearing mode (NTM) control system for DIII-D, which uses six sets of real-time steerable mirrors in order to move the electron cyclotron current drive (ECCD) deposition location in plasma. [•] This algorithm accurately finds the NTM island location employing motional Stark effect EFIT MHD equilibrium reconstruction. [•] Successful NTM suppression and preemption has been achieved in DIII-D using this control system to automatically switches on and off gyrotrons when NTM is detected and rapidly align the NTM island and the ECCD deposition location. [Copyright &y& Elsevier]

Highlights: [•] A 3.6MW (−66kV/55A) gyrotron power supply system was developed for the 170GHz ECH system in KSTAR. [•] The main power supply includes a total of 32 PSM based HV power supply modules. [•] The voltage regulation of individual HV power module and LV power module is 3kV and 0.5kV, respectively. [•] The gyrotron is protected by means of a fast solid-state switch (MOS-FET). [•] The HV switching system can turn off the 60kV to the cathode within 3μs in the event of gyrotron faults. [Copyright &y& Elsevier]