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In magnetic confinement fusion devices, supersonic molecular beam injection (SMBI) is commonly used as a fueling method, which has also performed well in physical studies since it was first proposed on the HL-1 tokamak by Southwestern Institute of Physics. This study presents the development of the SMBI technique since its first use in fusion experimental devices and reviews the progress on the investigation of plasma physics using the SMBI. In addition, this study further discusses the potential applications of the SMBI technique on future fusion devices.

A hard X-ray pinhole camera system has been recently built at the HL-2A tokamak to measure the evolution of space-time distribution of fast electrons in the energy range of 20 to 200 keV. The camer...

International audience; A multi-machine study has been carried out to investigate the impact of a strongly bounded wave propagation domain on the Lower Hybrid current drive, a condition which occurs principally in high aspect ratio tokamaks. In this regime, the condition of kinetic resonance can be far above the upper boundary of the propagation domain, and may not be achieved by the usual toroidal upshift. Therefore no tail of fast electrons can be pulled out from the thermal bulk. Nevertheless, while tokamak plasmas are in principle almost transparent to the wave in this regime so-called "unbridgeable spectral gap", full current drive is well achieved for the two tokamaks considered in this study, TRIAM-1M [H. Zushi, et al., Nucl. Fusion 43 (2003) 1600] and WEST [C. Bourdelle, et al., Nucl. Fusion 55 (2015) 063017], both characterized by a very large aspect ratio R/a > 5.5. The case of the high aspect ratio tokamak HL-2A [Y. Liu et al. Nucl. Fusion 45 (2005) S239] for which the wave propagation domain has also an upper boundary, but close to the resonance condition, is considered by comparison. First principles modeling of the rf-driven current and the fast electron bremsstrahlung using the ALOHA/C3PO/LUKE/R5-X2 chain of codes shows unambiguously that the spectral gap must be already filled at the separatrix in order to reproduce quantitatively observations and some important parametric dependencies. This result is an important milestone in the physics understanding of the Lower Hybrid current drive, highlighting the existence of a powerful and likely universal alternative mechanism to bridge the spectral gap, that is not related to toroidal magnetic refraction. With an initially broad power spectrum, lobes with low parallel refractive indexes that carry most of the plasma current can be absorbed in almost single pass, restoring the full validity of the ray-tracing approximation for describing the propagation of the Lower Hybrid wave in cold plasmas.

International audience; High-βθe (a ratio of the electron thermal pressure to the poloidal magnetic pressure) steady-state long-pulse plasmas with steep central electron temperature gradient are achieved in the Experimental Advanced Superconducting Tokamak. An intrinsic current is observed to be modulated by turbulence driven by the electron temperature gradient. This turbulent current is generated in the countercurrent direction and can reach a maximum ratio of 25% of the bootstrap current. Gyrokinetic simulations and experimental observations indicate that the turbulence is the electron temperature gradient mode (ETG). The dominant mechanism for the turbulent current generation is due to the divergence of ETG-driven residual flux of current. Good agreement has been found between experiments and theory for the critical value of the electron temperature gradient triggering ETG and for the level of the turbulent current. The maximum values of turbulent current and electron temperature gradient lead to the destabilization of an m/n =1/1 kink mode, which by counteraction reduces the turbulence level (m and n are the poloidal and toroidal mode number, respectively). These observations suggest that the self-regulation system including turbulence, turbulent current, and kink mode is a contributing mechanism for sustaining the steady-state long-pulse high-βθe regime

Active control of the excessively high heat and particle fluxes on the divertor target plates is of fundamental importance to the steady state operation of tokamaks, especially for fusion reactors. A series of experiments have been carried out on this critical issue to relieve the plasma-wall interactions in the experimental advanced superconducting tokamak (EAST) in the last ten years, not only contributing to the long pulse operation of EAST itself, but also providing physical understandings and potential techniques to the next-generation devices like ITER. We have characterized the power deposition pattern and broadened the divertor footprint width effectively. The plasma-wetted area is actively handled using either 3-dimentional edge magnetic topology or advanced plasma equilibrium, thereby peak heat flux around the strike point is reduced. Active control of detachment or radiation compatible with core plasma performance has progressed significantly in very recent years, with a series of active feedback control modules developed and utilized successfully, based on the divertor physics advances with both experiments and simulation. The upper divertor of EAST was upgraded from graphite to active water-cooling ITER-like tungsten in 2014, exhibiting much enhanced heat removal capability. As for the particle exhaust including both fueling and impurity particles, in addition to wall conditioning and impurity source control, the efficiency of particle flux exhaust is optimized by making full use of the divertor closure and the plasma drifts in both scrape-off layer and divertor volume. These heat and particle exhaust advances contribute greatly to a series of EAST achievements like H-mode operation over 100 s. A brief near-term plan on the integrated control of divertor plasma-wall interactions in long-time scale will also be introduced, aiming to provide favorable divertor operation solution for ITER and CFETR.

Studies on nonlinear interactions and multi-scale physics are crucial in the physical understanding of the turbulence and transport in the complex nonlinear system of fusion plasmas. This paper reviews recent studies on the turbulence and the related transport. The prominent results are mainly from tokamaks, such as HL-2A, Tore Supra and J-TEXT. First, turbulence behaviors and its role in transport will be introduced. Critical gradients in heat and particle transports have been observed and reproduced by simulations. Turbulence modes and its role in the transport are identified using advanced diagnostics. The measured turbulence transition is consistent with the observation of particle convection reversal and the simulation prediction. In addition, the excitation of an electromagnetic turbulence by either edge self-accumulated or externally seeded impurities has been observed. The impurity-driven turbulence plays an essential role in regulating the impurity transport. Then, the effect of plasma flows on turbulence and multi-scale interactions (micro-turbulence, meso-scale fluctuations, and large scale MHD activities) will be presented. Moreover, a new meso-scale electrostatic fluctuation has been observed. The results indicate that geodesic acoustic modes and magnetic fluctuations can transfer energy through nonlinear synchronization. At last, the enhancement of nonlinear interactions by external actuators will be reported. Theoretical studies in comparisons with experimental findings will be discussed.

Resonance effects play an important role in the transport properties of low-dimensional systems. Here, we investigate the thermally driven spin-transport properties of ruthenium-terpyridine molecular devices, where the molecule is linked to graphene electrodes by the carbon atomic chains from two sides. The results show that an odd-even oscillating behavior of the transmission spectra and a perfect spin-filtering effect at the Fermi level are observed in the ruthenium-terpyridine molecular devices. Furthermore, the negative differential thermoelectric resistance more easily appears in the long even-numbered carbon atomic chains, and the sign of the thermally driven single-spin current can be tuned via the temperature. Such a behavior is attributed to the competition between the Breit-Wigner and Fano resonances in the vicinity of the Fermi level for the contributions of the thermally driven current. In brief, here we present an alternative to control the thermally driven single-spin current in molecular devices via quantum effect.

In February 2018, one 54-year-old male patient with severe scald complicated with pneumonia and sepsis was transferred to Qingdao Municipal Hospital from other hospital. Drugs including cephalosporin, vancomycin, and imipenem/cilastatin combined with ciprofloxacin were used successively for anti-infective treatment, with no obvious effect. Multiple bacterial culture results of sputum, blood, and wound exudate showed infection of extensively drug resistant2018年2月，青岛市市立医院收治1例经外院转入的严重烫伤合并肺炎和脓毒症的54岁男性患者。先后使用头孢菌素、万古霉素、亚胺培南/西司他丁＋环丙沙星等抗感染治疗，但无明显效果。痰液、血液及创面分泌物多次细菌培养结果提示泛耐药铜绿假单胞菌感染。入院第4天调整抗感染治疗方案，补充血浆、红细胞及白蛋白，行营养支持及对症处理，同时进行用药监护，关注药物相关不良反应。经过10余天的治疗，患者感染得到有效控制，病情逐渐好转。本病例提示，严重烧伤患者易发生严重且致命的全身性感染，抗菌药物的不规范使用增加了泛耐药菌的感染风险，清晰的抗感染思路和抗菌药物的有效应用有助于提高感染治疗的成功率，对改善严重烧伤患者的预后具有重要价值。.

The redistribution of the divertor flux caused by the synergy of the supersonic-molecular-beam-injection (SMBI) and the magnetic perturbations induced by lower hybrid waves (LHWs), has been observed on the Experimental Advanced Superconducting Tokamak (EAST) [ Li J. {\it et al.} 2013 Nature Phys. 9 817]. To reveal the physical mechanism behind, first simulations with good qualitative agreements to the experimental findings are performed by utilizing a self-consistent fluid 3D edge plasma Monte-Carlo code coupled to a kinetic neutral particle transport code. The ions and electrons originating from the ionization of injected neutral particles in the plasma edge flow along the magnetic flux tube towards to the divertor, thus directly increasing the divertor flux on the split strike lines in the footprint. Combining this with the multi-lobe structure of the edge magnetic topology, actively controlling the divertor flux can be realized by adjusting the SMBI position or the phase of the magnetic perturbations.

This paper presents recent Lower Hybrid Current Drive (LHCD) progress in SWIP, including the experiments on HL-2A and system development on HL-2M. The 3.7GHz LHCD system was built on HL-2A, where the first Lower Hybrid Wave (LHW) coupling to H-mode plasma experiment via Passive-Active Multijunction (PAM) launcher was carried out. The coupled power has been increased much from 470kW to 1400kW since 2014. The LHW power became more and more important in the H-mode discharges on HL-2A in the past 4 years. In 2018, 1.1s ELMy H-mode was achieved with the help of Neutral Beam Injection (NBI) and LHW injection. However, The LHCD experiments showed distinct characteristic on HL-2A, i.e. no full non-inductive current drive (loop voltage never dropped below 0.3V) and counter-current drive effect found in the situation of co-current drive spectrum. Full non-inductive current drive was finally obtained after the spectrum turned opposite. Besides those achievements, the abnormal LHCD phenomenon discussion, full non-inductive current drive experiments, co-current and counter-current comparison, LHW deposition and mechanism of LHCD ELM mitigation are described. At the same time, a 4MW LHCD system is planned to be constructed on HL-2M. A 2MW LHCD system has been developed for HL-2M tokamak until now. Four TH2103C1 klystrons, transmission lines and a 4MW FAM antenna are included in this system. The other part will be built soon.

In saturated Ohmic confinement regime of the experimental advanced superconducting tokamak, significant changes in the relative electron temperature fluctuations T e / T ¯ e, measured by a correlation electron cyclotron emission system, have been observed. It was found that T e / T ¯ e is strongly dependent on the normalized electron temperature and density gradient, R / L T e = R ∇ T e / T e and R / L n e = R ∇ n e / n e. T e / T ¯ e stay at a high level when R / L T e is within the range of 17 − 25 and R / L n e is within the range of 4 − 6. It has been also observed that the energy confinement degradation is correlated with the increase in electron temperature fluctuations. The linear stability analysis results show that the electron temperature fluctuations are mainly attributed to the ion temperature gradient modes.

Shenshan sub-bituminous coal has been extracted with water at 200°C and 2 MPa. The resulting soluble mixture was separated into a deposit and a water-soluble fraction. The gas chromatography/mass spectrometry detectable species in both the deposit and the water-soluble fraction can be classified into linear molecules and cyclic molecules using the scaffold tree approach. The linear molecules consist of alkanes, acids, alkenes, alkanols, esters, ketones, aldehydes, ethers, nitrogen-containing organic compounds, and sulfur-containing organic compounds. The chemical structures of the cyclic molecules are more complicated and provide insight into the carbon skeleton structures and bridging linkages of the soluble molecules.

With a newly installed 5-channel W-band Doppler reflectometer (DR) in EAST tokamak, many interesting coherence modes and turbulences have been observed. In this paper, the tearing mode (TM), a novel inter-edge localized mode (ELM) electromagnetic mode, and the eigenmode geodesic acoustic mode (GAM) accompanied by a broadband quasi-coherent mode (QCM) during H-mode stage have been reported. The TM could be directly observed in both density fluctuation and perpendicular velocity fluctuation at the DR channel localized in the magnetic island region; moreover, many high-order TM frequency harmonics, dual turbulence peaks inside and outside the island separatrix, and strong flow shear across the island separatrix could also be observed. A high-frequency ( ∼ 230 kHz) electromagnetic mode (toroidal mode number n = 1) could be identified. The mode is generated dozens of milliseconds before the ELM crash and may affect the ELM dynamic process. The eigenmode GAM excited during the H-mode stage is generated near the top of the density pedestal and then propagates radially inward with a radial wavenumber of about 1 cm − 1. A broadband QCM with a frequency range of 20 – 100 kHz is always accompanied by eigenmode GAM and nonlinearly coupled with both GAM and the background turbulence from the bispectrum analysis. All these results convince the validity of the Doppler reflectometer in multi-scale measurement from the mesoscale to microscale.

The electrodeposition of nano-iron films from Fe2O3 precursor in an ionic liquid composed of 33·3 mol-% choline chloride (ChCl) and 66·7 mol-% ethylene glycol (EG) has been investigated. The electrodeposition process was carried out at 1·5–1·9 V and 60–120°C for 3 hours. The influences of experimental parameters on the electrodeposition process and the morphology of the deposited nano-iron films were studied. The results show that compact and uniform nano-iron (particle size is approximately 100–200 nm) films can be electrodeposited in the Fe2O3-saturated ChCl-EG ionic liquid at 1·8–1·9 V and 60–120°C. The electrodeposition temperature and applied potential have significant influences on the characteristics of the deposited nano-iron films and the electrodeposition process. It is suggested that the controllable electrodeposition process can be used to prepare nano-iron films with various particle sizes from Fe2O3 in CHCl-EG eutectic melt.

The impact of impurity ions on a pedestal has been investigated in the HL-2A Tokamak, at the Southwestern Institute of Physics, Chengdu, China. Experimental results have clearly shown that during the H-mode phase, an electromagnetic turbulence was excited in the edge plasma region, where the impurity ions exhibited a peaked profile. It has been found that double impurity critical gradients are responsible for triggering the turbulence. Strong stiffness of the impurity profile has been observed during cyclic transitions between the I-phase and H-mode regime. The results suggest that the underlying physics of the self-regulated edge impurity profile offers the possibility for an active control of the pedestal dynamics via pedestal turbulence.

The exact analytical solution of the one-dimensional diffusion equation in a cylinder has been found, for a medium characterized by a diffusion coefficient with step-like and/or monomial variations, in addition to a constant damping term. This type of equation has important applications in the field of magnetically confined plasmas, in the presence of a transport barrier. A sharp variation of the heat diffusivity can also result from the microturbulence that develops whenever the temperature gradient exceeds a critical value. This analytical solution can be used to model the evolution, in space and time, of the electron temperature of a plasma heated up by an external source, the step in the heat diffusion coefficient being related to the space location of the critical temperature gradient. The general properties of the solution and its application to the analysis of perturbative electron heating experiments are discussed.

Three methods to study the effect of density fluctuations on the reflected signal, based on a 2D full-wave analysis and Born approximation numerical and analytical calculations, are developed. The explicit analytical expression for the signal produced by an island-like perturbation running in poloidal direction is obtained and shown to be in nice agreement with results of numerical techniques for small level density perturbations. It is shown, both numerically and analytically, that due to small-angle scattering effects, fluctuations far from the cut-off layer may produce a significant and, in some realistic cases, dominant response. The conditions under which the fluctuation reflectometry signal is generated only in the cut-off vicinity are given.

A critical challenge facing the basic long-pulse high-confinement operation scenario ($H$ mode) for ITER is to control a magnetohydrodynamic (MHD) instability, known as the edge localized mode (ELM), which leads to cyclical high peak heat and particle fluxes at the plasma facing components. A breakthrough is made in the Experimental Advanced Superconducting Tokamak in achieving a new steady-state $H$ mode without the presence of ELMs for a duration exceeding hundreds of energy confinement times, by using a novel technique of continuous real-time injection of a lithium (Li) aerosol into the edge plasma. The steady-state ELM-free $H$ mode is accompanied by a strong edge coherent MHD mode (ECM) at a frequency of 35--40 kHz with a poloidal wavelength of 10.2 cm in the ion diamagnetic drift direction, providing continuous heat and particle exhaust, thus preventing the transient heat deposition on plasma facing components and impurity accumulation in the confined plasma. It is truly remarkable that Li injection appears to promote the growth of the ECM, owing to the increase in Li concentration and hence collisionality at the edge, as predicted by GYRO simulations. This new steady-state ELM-free $H$-mode regime, enabled by real-time Li injection, may open a new avenue for next-step fusion development.

Collective light scattering measurement is a powerful tool for investigating fluctuations and their relation with anomalous transport since it allows a direct, discriminating analysis of the turbulent scales. This high scale resolution has a counterpart in a poor spatial resolution, but some localization can be recovered allowing us to discriminate edge from core turbulence behavior and to determine turbulence profiles. More information about localization can be obtained using temporal dynamics of the scattered signal when the fluctuation velocity in the poloidal plane is sheared. Making use of the consequently separated Doppler shifts, different technics are used to extract localized information from frequency spectra and from the signal phase derivative. Capabilities of the diagnostic are illustrated by recent results obtained on Tore Supra in different regimes.

Edge cooling experiments have been performed in Tore Supra by impurity injection and oblique pellet injection. Non-local transport (NLT) features have been confirmed in both cases in the ohmic regime. The pellet injection experiments have shown the existence of a threshold on the plasma density ne and current Ip for the observation of this effect: ne/Ip1/2?1.0?1016?(m-3?A-1/2). A second threshold on the relative density variation caused by the pellet injection has also been observed: ?ne/ne?0.5. It has been observed that in the L regime during lower hybrid current drive (LHCD) experiments these limits are extended: [ne/Ip1/2]crit = 1.4?1016?(m-3?A-1/2) and [?ne/ne]crit?0.65. Observations in a LHCD scheme with fully non-inductive plasma current seem to indicate that the mechanism governing the NLT is unlikely to be linked to the plasma current profile effects including the spatial redistribution, the magnetic shear, and the low-m MHD modes.

The phase shift due to the resonant Bragg scattering of an ordinary wave in a fluctuating plasma is numerically computed for large amplitude density fluctuations, i.e. well beyond the Born approximation. The phase response (the phase shift against the perturbation position in the density gradient) is strongly distorted with respect to the small amplitude case, and phase jumps occur. For localized quasi-monochromatic fluctuations, the results are explained by an analytical model where the Helmholtz equation is approximated by a Mathieu equation. The maximum phase shift and the phase jumps are well predicted by the model. It turns out that the theoretical predictions also apply to moderate amplitudes. For an actual phase measurement where the number of different frequencies (i.e. the number of perturbation positions) is finite, most phase jumps are missed, due to the steepness of the phase jumps, and the measured phase shift increases continuously.

The frequency modulated continuous wave reflectometer was developed for the first time on the HL-2A tokamak. The system utilizes a voltage controlled oscillator and an active multiplier for broadband coverage and detects as heterodyne mode. Three reflectometers have been installed and operated in extraordinary mode polarization on HL-2A to measure density profiles at low field side, covering the Q-band (33–50 GHz), V-band (50–75 GHz), and W-band (75–110 GHz). For density profile reconstruction from the phase shift of the probing wave, a corrected phase unwrapping method is introduced in this article. The effectiveness of the method is demonstrated. The density profile behavior of a fast plasma event is presented and it demonstrates the capability of the reflectometer. These diagnostics will be contributed to the routine density profile measurements and the plasma physics study on HL-2A.

A parametric experimental study of fluctuations has been performed in L-mode plasmas during steady-state phases in Tore Supra. Simultaneous measurements of density and magnetic fluctuations in the gradient region of the discharge show that both components are strong functions of the local electron temperature decreasing lengths. The wavenumber spectrum of density fluctuations is obtained with the scattering diagnostic both in the bulk and at the edge of the discharge. In the bulk, in the L-mode compared to ohmic plasmas, the k spectrum increases below and is globally shifted towards low k values. At the edge (r/a > 0.9) an increase on all k values is observed. At r/a = 0.5, the level of both types of fluctuations is found to be linearly correlated with the local heat diffusivity . The heat flux ratio advected by electrostatic eddies in the bulk of the discharge is estimated by using fluctuation measurements and generic predictions for the parametric dependency of the thermal flux. The calculated level of density fluctuation necessary to account for the heat transport at midradius is found to be compatible with values measured in other tokamaks. It is also found that the heat flux ratio behaviour conducted by electrostatic fluctuations is compatible with most of the experimental heat flux ratio behaviour in the plasma core (0.4 < r/a < 0.6). This property does not hold at the edge of the plasma (r/a = 0.7). The similar parametric dependency of magnetic and density fluctuation level does not allow one to make a clear statement about their relative importance in the transport process and suggests that they could be coupled.

Particle transport has been studied in the Tore Supra tokamak by using modulated ion cyclotron resonance heating to generate perturbations of density and temperature. For the first time, a reversal of the particle convective velocity and a strong increase in the turbulent particle flux have been clearly observed. When the mixed critical gradient ${\ensuremath{\zeta}}_{c}=R/{L}_{T}+4(R/{L}_{n})=22$ is exceeded, the particle flux increases sharply and the convective velocity reverses from inward to outward. These observations are in agreement with quasilinear, gyrokinetic calculations. The critical gradient corresponds to a transition from an instability driven by the ion temperature gradient to the onset of another instability caused by trapped electrons.

The dynamic features of the low-intermediate--high-(L-I-H) confinement transitions on HL-2A tokamak are presented. Here we report the discovery of two types of limit cycles (dubbed type-$Y$ and type-$J$), which show opposite temporal ordering between the radial electric field and turbulence intensity. In type-$Y$, which appears first after an L-I transition, the turbulence grows first, followed by the localized electric field. In contrast, the electric field leads type-$J$. The turbulence-induced zonal flow and pressure-gradient-induced drift play essential roles in the two types of limit cycles, respectively. The condition of transition between types-$Y$ and -$J$ is studied in terms of the normalized radial electric field. An I-H transition is demonstrated to occur only from type-$J$.

Ordinary wave reflectometry in a plasma containing a localized density perturbation is studied with a one-dimensional (1D) model. The phase response is studied as a function of the wavenumber and position of the perturbation. It is shown that it strongly depends upon the perturbation shape and size. For a small perturbation wavenumber, the response is due to the oscillation of the cut-off layer. For larger wavenumbers, two regimes of resonant Bragg scattering are found: for a broad perturbation, the phase response is an image of the perturbation itself; for a narrow perturbation, it is an image of the Fourier transform. These features are enhanced for a broadband perturbation (modulated square wave) and scattering can occur over the whole region up to the cut-off. Furthermore, in that case there is a specific behaviour at the cut-off due to the sharp boundary effects of this perturbation. Because of this peculiarity, the phase response obtained for a damped square perturbation reproduces the results of an earlier experiment (Rhodes et al, Rev. Sci. Instrum. 1992).

A qualitative model which includes three loops of zonal flow vs. turbulence and turbulence vs. pressure gradient is proposed for the experimentally observed two types of limit cycle oscillations (LCOs) and low-intermediate-high (L-I-H) confinement transitions. The experimental evidences supporting the model and revealing the roles of turbulence– and pressure-gradient–induced flows in triggering the H-mode at marginal heating power in tokamak plasmas are presented. The dominant role played by pressure-gradient–induced flows in I-phase of type-J LCO as well as I-H transition is demonstrated, along with that done by the turbulent-Reynolds-stress–driven zonal flows in the L-I transition as well as I-phase of type-Y LCO. The trigger and conditions for the I-H transition are identified from the experimental observations.

Several discharges have been analysed in Tore Supra in order to improve the understanding of anomalous transport. In ohmic discharges, it has been shown that both particle and heat diffusion coefficients improve with increasing density, then saturate. The level of edge density fluctuations behave in the same way. In the presence of additional heating, the bulk and the edge turbulences behave differently. The level of edge density fluctuations remains constant in most discharges with additional heating (up to 8 MW). In practice, it only depends on edge conditions. On the contrary, the level of core magnetic fluctuations increases systematically with any additional power. Finally, a lowering of the level of the edge density fluctuations has been observed when using the Tore Supra ergodic divertor. This improvement is accompanied by the onset of a temperature pedestal between the plasma bulk and the ergodic layer. This explains why the global confinement remains unchanged in presence of the ergodic divertor in spite of the reduced radius of the last closed magnetic surface.

The Choi-Williams distribution (CWD) technique is introduced as a time-frequency tool for processing data measured from the new developed homodyne and the fixed frequency reflectometry in the HL-2A tokamak. The comparison between spectrogram and CWD for the simulated signal is presented. It indicates that the CWD can greatly improve the representation of the time-frequency content of the multi-components signal. Its effectiveness is demonstrated through two applications in HL-2A, which are the extraction of beat frequencies from the frequency modulated-continuous wave reflectometry (FM-CW) and the characterizing of the fluctuations. The density profile inversed from the group delay of the FM-CW and the density fluctuations deduced from the fixed-frequency reflectometry would be more reliable and accurate by using the CWD technique.

Linear ionic instability thresholds are numerically calculated for tokamaks. Proof is given that the stability domain is determined by trapped‐ion modes for positive values of ηi=d(log Ti) /d(log ni). The boundary is characterized by ηi≥1 and a threshold LTi/R of order 0.2/(1+Ti/Te). This value is significantly smaller than previously predicted. Experimental temperature profiles in additionally heated discharges are usually marginal with respect to this criterion. It is also shown that marginal eigenmodes are low‐frequency, low‐wave‐number modes, which may produce a very large transport once the ion temperature gradient threshold is reached.

The main results of the Tore Supra experimental programme in the years 2007–2008 are reported. They document significant progress achieved in the domain of steady-state tokamak research, as well as in more general issues relevant for ITER and for fusion physics research. Three areas are covered: ITER relevant technology developments and tests in a real machine environment, tokamak operational issues for high power and long pulses, and fusion plasma physics. Results presented in this paper include test and validation of a new, load-resilient concept of ion cycotron resonance heating antenna and of an inspection robot operated under ultra-high vacuum and high temperature conditions; an extensive experimental campaign (5 h of plasma) aiming at deuterium inventory and carbon migration studies; real-time control of sawteeth by electron cyclotron current drive in the presence of fast ion tails; ECRH-assisted plasma start-up studies; dimensionless scalings of transport and turbulence; transport experiments using active perturbation methods; resistive and fast-particle driven MHD studies. The potential role of Tore Supra in the worldwide fusion programme before the start of ITER operation is also discussed.

The problem of wave scattering by fluctuations close to a cut-off layer is investigated. A generalized wavenumber selection rule is introduced. It provides a simple tool for analyzing the localization of scattering and defining which turbulence wavenumbers are at the origin of the observed scattered signal. Moreover, absolutely-calibrated measurements of fluctuation rates can be envisaged. Applications to four diagnostics (one- and two-antennae reflectometry, correlation reflectometry and cross-polarization scattering) are discussed.

A long-pulse high confinement plasma regime known as H-mode is achieved in the Experimental Advanced Superconducting Tokamak (EAST) with a record duration over 30 s, sustained by Lower Hybrid wave Current Drive (LHCD) with advanced lithium wall conditioning and divertor pumping. This long-pulse H-mode plasma regime is characterized by the co-existence of a small Magneto-Hydrodynamic (MHD) instability, i.e., Edge Localized Modes (ELMs) and a continuous quasi-coherent MHD mode at the edge. We find that LHCD provides an intrinsic boundary control for ELMs, leading to a dramatic reduction in the transient power load on the vessel wall, compared to the standard Type I ELMs. LHCD also induces edge plasma ergodization, broadening heat deposition footprints, and the heat transport caused by ergodization can be actively controlled by regulating edge plasma conditions, thus providing a new means for stationary heat flux control. In addition, advanced tokamak scenarios have been newly developed for high-performance long-pulse plasma operations in the next EAST experimental campaign.

China’s grassland has been undergoing rapid changes in the recent past owing to increased climate variability and a shift in grassland management strategy driven by a series of ecological restoration projects. This study investigated the spatio-temporal dynamics of Inner Mongolia grassland, the main grassland region in China and part of the Eurasia Steppe, to detect the interactive nature of climate, ecosystems and society. Land-use and landscape patterns for the period from 1985 to 2009 were analysed based on TM- and MODIS-derived land-use data. Net Primary Productivity (NPP) estimated by using the Carnegie-Ames-Stanford Approach model was used to assess the growth status of grassland. Furthermore, the factors related to the dynamics of grassland were analysed from the perspectives of two driving factors, climate change and human activities. The results indicated that higher temperatures and lower precipitation may generally have contributed to grassland desertification, particularly in arid regions. During the period from 1985 to 2000, a higher human population and an increase in livestock numbers were the major driving forces responsible for the consistent decrease in NPP and a relatively fragmented landscape. From 2000 to 2009, the implementation of effective ecological restoration projects has arrested the grassland deterioration in some ecologically fragile regions. However, a rapid growth of livestock numbers has sparked new degradation onnon-degraded or lightly degraded grassland, which was initially neglected by these projects. In spite of some achievement in grassland restoration, China should take further steps to develop sustainable management practices for climate adaptation and economic development to bring lasting benefits.

We have synthesized a range of hybrid classical/non-classical cannabinoids (CC/NCCs) combining the hexahydrocannabinol dibenzopyran structure with the hydroxyalkyl chain found in CP-55940, in order to investigate the role of the hydroxyalkyl pharmacophore in cannabimimetic activity. This was achieved by synthesizing CC analogs in which the 6 alpha- and 6 beta-methyl groups were modified to the corresponding hydroxyethyl groups. Our binding data indicated that beta position was the preferred orientation for the hydroxyalkyl moiety, affinity for the CB1 receptor being 20-fold greater for the 6 beta-hydroxyethyl than the corresponding 6 alpha-analog. Further studies using 6 beta-hydroxyalkyldibenzopyran analogs varying the southern aliphatic chain length from 6 beta-hydroxymethyl to 6 beta-hydroxyethyl to 6 beta-hydroxypropyl demonstrated little potency change with chain length. Therefore, we concluded that whilst the hydroxyalkyl pharmacophore was strongly affected by its configuration relative to the dibenzopyran ring, the chain length of the hydroxyalkyl moiety (up to the n = 3 homolog) was not critical.

A method of the particle transport study using supersonic molecular beam injection (SMBI) and microwave reflectometry is reported in this paper. Experimental results confirm that pulsed SMBI is a good perturbation source with deeper penetration and better localization than the standard gas puffing. The local density modulation is induced using the pulsed SMBI and the perturbation density is measured by the microwave reflectometry. Using Fourier transform analysis for the local density perturbation, radial profiles of the amplitude and phase of the density modulation can be obtained. The experimental results in HL-2A show that the particle injected by SMBI is located at about r/a=0.65-0.75. The position of the main particle source can be determined through three aspects: the minimum of the phase of the first harmonic of the Fourier transform of the modulated density measured by microwave reflectometry; the H(a) intensity profile and the local density increase ratio. The maximum of the amplitude of the first harmonic shifts often inward relative to the particle source location, which indicates clearly there is an inward particle pinch in this area. Good agreement has been found between the experimental results and the simulation using analytical transport model. The particle diffusivity D and the particle convection velocity V have been obtained by doing this simulation. The sensitivity in the transport coefficients of the amplitude and the phase of the density modulation has been discussed.

The utilization and development of nitrogen-fixing trees as resources has played an important role in establishing forests in denuded land, in producing more wood in industrial plantations, in conserving soil and water, and in improving ecosystems. A survey on the nodulation status of some tropical and subtropical woody leguminous species in Fujian Province and an investigation of the ecophysiology of symbiotic nitrogen fixation in several leguminous trees have been carried out in recent years.

Either transscleral cyclophotocoagulation with the contact neodymium:YAG (Nd:YAG) laser or cyclocryotherapy (CCT) was performed in rabbits to compare the efficacy of these procedures in reducing intraocular pressure (IOP) as well as the histologic changes they induced. The difference in mean maximum reduction of IOP in the two groups was statistically insignificant, but the Nd:YAG laser irradiation, using 2.5 J, destroyed less tissue than the CCT.

The analytical solution of the one-dimensional diffusion-convection equation in a cylinder has been found, for various functional forms of the diffusion coefficient, convection velocity and with an additional damping term. This is a significant generalization of a previous work [A. Clemencon, C. Guivarch, S. P. Eury, X. L. Zou, and G. Giruzzi, Phys. Plasmas 11, 4998 (2004)] on the diffusion equation, including now a convection term that can be constant, monomially increasing in the space coordinate, or have step-like variations. This type of equation has important applications in the field of magnetically confined plasmas, in which convection effects are experimentally observed in both particle and energy transports. Sharp variations of heat diffusivity, convection velocity, and damping term can result from the microturbulence which develops whenever the temperature gradient exceeds a critical value. A general scheme is developed to connect solutions in domains with different functional forms of the coefficients. The properties of the solutions are illustrated and discussed.

We demonstrate the possibility of measuring magnetic fluctuations in inhomogeneous hot plasma by cross polarization scattering (or linear mode conversion) of a pump wave. Application to fusion plasma, by magnetic probing in the core of a Tokamak, is considered using a combination of polarization reflectometry and scattering techniques.