Remotely controlling the movement of small objects is desirable, especially for the transportation and selection of materials. Transfer of objects between liquid and solid surfaces and triggering their release would allow for development of novel material transportation technology. Here, we describe the remote transport of a material from a water film surface to a solid surface using quasispherical liquid marbles (LMs). A light-induced Marangoni flow or an air stream is used to propel the LMs on water. As the LMs approach the rim of the water film, gravity forces them to slide down the water rim and roll onto the solid surface. Through this method, LMs can be efficiently moved on water and placed on a solid surface. The materials encapsulated within LMs can be released at a specific time by an external stimulus. We analyzed the velocity, acceleration, and force of the LMs on the liquid and solid surfaces. On water, the sliding friction due to the drag force resists the movement of the LMs. On a solid surface, the rolling distance is affected by the surface roughness of the LMs.

Two types of electrostatic modes with small-poloidal wave numbers (approximately 1 and 10-15 kHz) are observed in the edge region of Ohmically heated plasmas in the JFT-2M tokamak. The envelope of the higher frequency coherent mode is modulated at the frequency of the lower frequency mode. A bispectral analysis revealed that a significant nonlinear coupling among the two types of fluctuations and the broadband background turbulent potential fluctuations occurs inside the last closed magnetic flux surface, suggesting that a nonlinear process such as the parametric-modulational instability is involved.

The design progress in a compact low aspect ratio (low A) DEMO reactor, ‘SlimCS’, and its design issues are reported. The design study focused mainly on the torus configuration including the blanket, divertor, materials and maintenance scheme. For continuity with the Japanese ITER-TBM, the blanket is based on a water-cooled solid breeder blanket. For vertical stability of the elongated plasma and high beta access, the blanket is segmented into replaceable and permanent blankets and a sector-wide conducting shell is arranged inbetween these blankets. A numerical calculation indicates that fuel self-sufficiency can be satisfied when the blanket interior is ideally fabricated. An allowable heat load to the divertor plate should be 8 MW m−2 or lower, which can be a critical constraint for determining a handling power of DEMO.

The JT-60SA device has been designed as a highly shaped large superconducting tokamak with a variety of plasma actuators (heating, current drive, momentum input, stability control coils, resonant magnetic perturbation coils, W-shaped divertor, fuelling, pumping, etc) in order to satisfy the central research needs for ITER and DEMO. In the ITER- and DEMO-relevant plasma parameter regimes and with DEMO-equivalent plasma shapes, JT-60SA quantifies the operation limits, plasma responses and operational margins in terms of MHD stability, plasma transport and confinement, high-energy particle behaviour, pedestal structures, scrape-off layer and divertor characteristics. By integrating advanced studies in these research fields, the project proceeds ‘simultaneous and steady-state sustainment of the key performances required for DEMO’ with integrated control scenario development applicable to the highly self-regulating burning high-β high bootstrap current fraction plasmas.

An integrated SOL/divertor code is being developed by the JAEA (Japan Atomic Energy Agency) for interpretation and prediction studies of the behavior of plasmas, neutrals, and impurities in the SOL/divertor region. A code system consists of the 2D fluid code for plasma (SOLDOR), the neutral Monte-Carlo code (NEUT2D), the impurity Monte-Carlo code (IMPMC), and the particle simulation code (PARASOL). The physical processes of neutrals and impurities are studied using the Monte Carlo (MC) code to accomplish highly accurate simulations. The so-called divertor code, SOLDOR/NEUT2D, has the following features: 1) a high-resolution oscillation-free scheme for solving fluid equations, 2) neutral transport calculation under the condition of fine meshes, 3) successful reduction of MC noise, and 4) optimization of the massive parallel computer. As a result, our code can obtain a steady state solution within 3 ∼ 4 hours even in the first run of a series of simulations, allowing the performance of an effective parameter survey. The simulation reproduces the X-point MARFE (multifaceted asymmetric radiation from edge) in the JT-60U. It is found that the chemically sputtered carbon at the dome causes radiation peaking near the X-point. The performance of divertor pumping in the JT-60U is evaluated based on particle balances. In regard to the divertor design of the next tokamak of JT-60U, the simulation indicates the dependencies of pumping efficiency on the divertor geometry and operational conditions. The efficiency is determined by the balance between the incident and back-flow fluxes into and from the exhaust chamber.

Hydrophobic polypyrroles doped with perfluoroalkyl dopants can function as a liquid marble stabilizer with photothermal properties.

No abstract

An integrated divertor simulation code SONIC has been developed. The self-consistent coupling of an MC impurity code IMPMC to a divertor code SOLDOR/NEUT2D is succeeded by overcoming the intrinsic problems of Monte Carlo (MC) modelling for impurity transport. MC modelling for impurity transport is required in order to take into account the kinetic effect and the complex dissociation processes of hydrocarbons. The integrated divertor code SONIC enables us to investigate the details of impurity transport including erosion/redeposition processes on the divertor plates by further coupling of an MC code EDDY. The dynamic evolution of X-point MARFE observed in JT-60U is investigated. The simulation results indicate that the hydrocarbons sputtered from the dome contribute directly to the enhanced radiation near the X-point. Without the recycling, the kinetic effect of the thermal force improves the helium compression, compared with the conventional (fluid) evaluation. This effect is, however, masked by the recycling at the divertor targets.