Simulations of neutral beam injection and ion cyclotron resonance heating synergy in high power EAST scenarios.

The EAST plasmas heated with deuterium neutral beam injection and ion cyclotron resonance heating (ICRH) have been simulated by the TRANSP code. The analysis has been conducted using the full wave solver TORIC5, the radio frequency (RF)-kick operator, and NUBEAM to model the RF heating effects on fast ion velocity distribution. In this work, we present several simulated results compared with experiments for high power EAST scenarios, indicating that the interactions between ICRH and fast ions can significantly accelerate fast ions, which are confirmed by the increased neutron yield and broadened neutron emission spectrum measurements.

Analgesic benefits of the quadratus lumborum block in total hip arthroplasty: a systematic review and meta-analysis.

The quadratus lumborum block (QLB) is reported to reduce pain and improve function following total hip arthroplasty; however, randomised controlled trials evaluating the benefits of adding this block to general or spinal anaesthesia in this population are conflicting. We performed a systematic review seeking randomised controlled trials investigating QLB benefits for total hip arthroplasty, stratifying comparisons regarding the addition of QLB to either general or spinal anaesthesia. The primary outcome was 24-h area under the curve (AUC) pain score. Pain scores were interpreted in the context of a population-specific minimal clinically important difference of 1.86 cm on a 10-cm visual analogue scale, or an AUC pain score of 5.58 cm.h. Secondary outcomes included analgesic consumption, functional recovery and opioid-related side-effects. In all, 18 trials (1318 patients) were included. Adding QLB to general or spinal anaesthesia improved 24-h AUC rest pain scores by a mean difference (95%CI) of -3.56 cm.h (-6.70 to -0.42; p = 0.034) and - 4.19 cm.h (-7.20 to -1.18; p = 0.014), respectively. These improvements failed to reach the pre-determined minimal clinically important difference, as did the reduction in analgesic consumption. Quadratus lumborum block improved functional recovery for general, but not spinal, anaesthesia. Opioid-related side-effects were reduced with QLB regardless of anaesthetic modality. Low-to-moderate quality evidence suggests that the extent to which adding QLB to either general or spinal anaesthesia reduces postoperative pain and opioid consumption after total hip arthroplasty is statistically significant but may be clinically unimportant for most patients. However, adding QLB to general anaesthesia might enhance functional recovery. Taken together, our findings do not support the routine use of QLB as part of multimodal analgesic regimens for total hip arthroplasty.

Experimental Evidence of Intrinsic Current Generation by Turbulence in Stationary Tokamak Plasmas.

High-ß_{θe} (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-ß_{θe} regime.

Neutron emission and fast ion simulation for high performance long pulses at EAST.

Neutron emission spectroscopy and neutron yield measurements are important for high neutral beam injection (NBI) power heating at the Experimental Advanced Superconducting Tokamak (EAST). The neutron yields mainly depend on the deposition from NBI to the deuterium plasmas in the EAST. We have recently used TRANSP with time dependent diagnostic results to simulate the transport process of 30 s long pulse deuterium plasma discharges in the EAST, obtaining the time dependent fast ion distribution, neutron emission spectrum, and total neutron emission rate. Combined with the time trace of the result measured by a standard 235U fission chamber, the effects of different configurations of NBI heating in EAST fusion plasmas have been evaluated.

A compact stilbene crystal neutron spectrometer for NBI-heated plasma neutron diagnostics at EAST.

Stilbene crystal detectors are widely used as fast neutron measurement tools based on recoil proton detection, such as liquid scintillators. A compact stilbene crystal neutron spectrometer (CSCNS) has been installed at the Experimental Advanced Superconducting Tokamak (EAST) to obtain information on fuel ions produced in the plasma core because of its merits of good n/γ discrimination capability, high detection efficiency, and fast response. For the first time, CSCNS has been used for neutron emission spectroscopy measurements in EAST plasmas with neutral beam injection (NBI) heating. The CSCNS has the same horizontal line of sight as the time-of-flight enhanced diagnostics neutron spectrometer. Under NBI heating scenarios, the time trace of the neutron yield monitored by the CSCNS is similar to the one monitored by a standard 235U fission chamber. The experimental pulse height spectra are also similar to the simulated ones generated by folding the simulated neutron energy spectrum with the detector response functions. These results demonstrate the capability of the CSCNS for neutron diagnostics and the study of fast-ion physics in EAST.

The cross-polarization scattering system for the magnetic fluctuation measurement in the Experimental Advanced Superconducting Tokamak.

The cross-polarization scattering (CPS) system for magnetic fluctuation measurements in the Experimental Advanced Superconducting Tokamak (EAST) has been designed and installed. Different from the Doppler reflectometer (DR) system, the CPS system detects the perpendicular polarization of the electromagnetic wave induced by magnetic fluctuations B̃. The CPS system in the EAST has been developed from the existing Doppler reflectometer system, and they are integrated together for simultaneous measurement of magnetic and density fluctuations. Ray-tracing simulations are used to calculate the scattering locations and the wavenumber coverage of the magnetic fluctuation for CPS. In the experiments, the CPS and DR system data were different in Doppler shift, amplitude, and spectrum broadening. In this article, the hardware design, the ray tracing, and the preliminary results of the system in the EAST are presented.

Global public interest in systemic lupus erythematosus: an investigation based on internet search data.

OBJECTIVE: This study aims at investigating the global public interest in seeking information about systemic lupus erythematosus (SLE) using Google Trends (GT). METHODS: An electronic search was performed using GT with the search term lupus as well as the option of disease from January 2004 to December 2018. Cosinor analysis was applied to detect the seasonality of SLE-related relative search volume (RSV). In addition, analysis on SLE-related topics including "hot topics" and "top rising topics" was also conducted. RESULTS: Overall, SLE-related RSV showed a decreasing trend from January 2004 to December 2013 and then demonstrated a slowly increasing trend from January 2014 to December 2018. Cosinor test showed no significant seasonal variation in SLE-related RSV (p > .025). RSV peaked in May and reached the trough in November. The top seven rising topics were Selena Gomez, Sjögren syndrome, autoimmunity, rheumatoid arthritis, rheumatology, antinuclear antibody and autoimmune disease. CONCLUSION: The results from GT analysis showed slowly increasing internet searches for SLE in recent years. This trend was followed by a peak of RSV in May and reached its lowest level in November. However, globally, the results did not reveal a significant seasonal variation in GT for SLE. Additionally, the top fast-growing topics regarding SLE may be valuable for doctors and nurses to provide timely education of the disease to patients, as well as promote the development of public health.

[The clinical significance of serum C1q tumor necrosis factor-related protein-9 (CTRP9) in patients with cerebral infarction].

To explore the clinical significance of C1q tumor necrosis factor-related protein-9 (CTRP9) in patients with cerebral infarction. Our data showed that the serum CTRP9 was significantly lower than that of control group, especially in patients with large artery atherosclerotic cerebral infarction. CTRP9 was first decreased and even lower from day 4 to day 10, then gradually elevated. Logistic regression analysis suggested that high CTRP9 level was a protective factor for cerebral infarction. Thus, CTRP9 could be a factor for further classification of cerebral infarction and provides a potential option for disease prevention and treatment.

Five-channel tunable W-band Doppler backscattering system in the experimental advanced superconducting tokamak.

A 5-channel Doppler backscattering system has been designed and installed in the Experimental Advanced Superconducting Tokamak (EAST). Through an I/Q-type double sideband modulator and a frequency multiplier, an array of finely spaced (Δf = 400 MHz) frequencies that span 1.6 GHz has been created. The center of the array bandwidth is tunable within the range of 75-97.8 GHz, which covers most of the W band (75-110 GHz). The incident angle can be adjusted from -4° to 12°, and the wavenumber range is 4-15 cm-1 with a wavenumber resolution of Δk/k ≤ 0.35. Ray tracing is used to calculate the scattering location and the scattering wavenumber. This article details the hardware design, the ray tracing, and the preliminary experimental results from EAST plasmas.

Experimental examination of a method to estimate temporal effect by neutrons and γ-rays on scintillation light in scintillator-based soft x-ray diagnostic of experimental advanced superconducting tokamak and large helical device.

Scintillators, which are more tolerant of neutrons or γ-rays than semiconductors, are a promising candidate for soft X-ray (SX) diagnostics in high neutron flux environments such as JT-60SA or ITER. Although scintillators are tolerant of radiations, neutrons and γ-rays can cause scintillation light and become noise on SX signals. Therefore, a method to estimate the temporal effect by the radiations on SX signals and an appropriate design of the radiation shield based on the estimation are required. In previous studies, it has been proposed for estimating the effect by the radiations to calculate the absorption powers due to SXs, neutrons, and γ-rays in scintillators assuming that amplitudes of scintillation light are proportional to the absorption powers. In this study, an experimental examination of this proposal is conducted in the Experimental Advanced Superconducting Tokamak (EAST). It is shown that the proposal may be valid in the examination of EAST. In addition to results in EAST, initial results of a multi-channel scintillator-based SX diagnostic in the Large Helical Device (LHD) are introduced. Although a scintillator-based SX diagnostic in LHD observes oscillations of SXs by magnetohydrodynamic (MHD) phenomena successfully, the observed temporal effect on SX signals by neutrons or γ-rays is more significant than the expected effect, which is estimated by calculating the absorption powers. One of the possible reasons for the contradiction between the results in EAST and LHD is unexpected γ-rays around the scintillators in LHD. Although the temporal effect by the radiations is significant in the current system of LHD, the degradation of amplitudes of SX signals after the deuterium plasma experiments is not observed with the current level of the fluence. The scintillator-based SX diagnostic in LHD may work as a diagnostic to research MHD instabilities in deuterium plasma experiments without additional maintenance during an experimental campaign by making the pinhole larger or setting an additional radiation shield.

Development of gamma ray spectrometer with high energy and time resolutions on EAST tokamak.

A new gamma ray spectrometer with high energy and time resolutions has been developed and installed on the EAST tokamak to study fast ion and runaway electron behaviors. The spectrometer is based on a LaBr3(Ce) scintillator detector and a fully digital data acquisition system that is based on a digitizer with digital pulse processing algorithms. The energy resolution of the spectrometer is about 3.9% at 662 keV, and the spectrometer can operate stably at a counting rate as high as 1 MHz, monitored by using a light emitting diode monitoring system. The measured gamma ray spectrum is simulated based on Geant4 and unfolded with the high-resolution boosted Gold deconvolution algorithm, aiming at reconstructing the energy distribution functions of fast ions and runaway electrons.

Velocity-space sensitivity of time-of-flight neutron spectrometer at EAST in deuterium plasma.

The Time-Of-Flight Enhanced Diagnostics (TOFED) neutron spectrometer with a double-ring structure has been installed at the Experimental Advanced Superconducting Tokamak (EAST) to perform advanced neutron emission spectroscopy diagnosis for deuterium plasma. In order to reduce the random coincidence from the background neutrons and gamma-rays, TOFED was moved outside the experimental hall and placed in the newly-built nuclear diagnostics laboratory in 2017. In this paper, the instrument-specific weight functions of TOFED are derived by taking the instrument response matrix and the radial line of sight in this new layout into consideration. The results show that the instrument is predominantly sensitive to counter-passing particles in the region where time-of-flights < 69.4 ns, while events at higher time-of-flights (corresponding lower neutron energies) are mostly representative of co-passing ions. The instrument-specific weight functions express the relationship between data in a given channel of the spectrum and the velocity space region that contributes to that. The results can be applied for energetic particle physics studies at EAST, in particular to compare data from different diagnostic techniques.

Performance of fast-ion loss diagnostic on EAST.

The scintillator-based detector for fast-ion loss measurements has been installed on EAST. To obtain high temporal resolution for fast-ion loss diagnostics, fast photomultiplier tube systems have been developed which can supply the complementary measurements to the previous image system with good energy and pitch resolution by using a CCD camera. By applying the rotatable platform, the prompt losses of beam-ions can be measured in normal and reverse magnetic field. The thick-target bremsstrahlung occurring in the stainless steel shield with energetic electrons can produce X-rays, which will strike on the scintillator based detector. To understand this interference on fast-ion loss signals, the effects of energetic electrons on the scintillator-based detector are studied, including runaway electrons in the plasma ramping-up phase and fast electrons accelerated by the lower hybrid wave.

Velocity-space sensitivity of the compact neutron emission spectrometers at EAST.

Several compact neutron spectrometers are now installed at EAST (Experimental Advanced Superconducting Tokamak) to obtain information on fuel ions produced in the core of the plasma. In this paper, a stilbene crystal neutron spectrometer and an EJ301 liquid scintillator neutron spectrometer with n-γ discrimination capability will be discussed. Both spectrometers have a horizontal line of sight, while at different positions. In the last few experiment campaigns at EAST, they all proved to be reliable diagnostics for auxiliary heated D-D plasmas. Taking the response function simulated by dedicated Geant4 models into consideration, the velocity-space sensitivities given by the instrument-specific weight function of the beam-thermal part of neutron energy spectra in D-D plasmas are derived for both spectrometers with the Genesis code. This method makes it possible to directly relate the contribution of different deuteron velocity space regions to events in each channel of the neutron spectrum measured by the two instruments: http://rsi-htpd.peerx-press.org/.

Non-inductive vertical position measurements by Faraday-effect polarimetry on EAST tokamak.

Vertical instability control in an elongated plasma is highly desirable for a tokamak reactor. A multi-channel 694 GHz far-infrared laser-based polarimeter-interferometer system has been used to provide a non-inductive vertical position measurement in the long-pulse EAST tokamak. A detailed comparison of vertical position measurements by polarimetry and external inductive flux loops has been used to validate Faraday-effect polarimetry as an accurate high-time response vertical position sensor.

Scintillator-based fast ion loss measurements in the EAST.

A new scintillator-based fast ion loss detector (FILD) has been installed on Experimental Advanced Superconducting Tokamak (EAST) to investigate the fast ion loss behavior in high performance plasma with neutral beam injection (NBI) and ion cyclotron resonance heating (ICRH). A two dimensional 40 mm × 40 mm scintillator-coated (ZnS:Ag) stainless plate is mounted in the front of the detector, capturing the escaping fast ions. Photons from the scintillator plate are imaged with a Phantom V2010 CCD camera. The lost fast ions can be measured with the pitch angle from 60° to 120° and the gyroradius from 10 mm to 180 mm. This paper will describe the details of FILD diagnostic on EAST and describe preliminary measurements during NBI and ICRH heating.

Initial measurements of plasma current and electron density profiles using a polarimeter/interferometer (POINT) for long pulse operation in EAST (invited).

A double-pass, radially viewing, far-infrared laser-based POlarimeter-INTerferometer (POINT) system utilizing the three-wave technique has been implemented for diagnosing the plasma current and electron density profiles in the Experimental Advanced Superconducting Tokamak (EAST). POINT has been operated routinely during the most recent experimental campaign and provides continuous 11 chord line-integrated Faraday effect and density measurement throughout the entire plasma discharge for all heating schemes and all plasma conditions (including ITER relevant scenario development). Reliability of both the polarimetric and interferometric measurements is demonstrated in 25 s plasmas with H-mode and 102 s long-pulse discharges. Current density, safety factor (q), and electron density profiles are reconstructed using equilibrium fitting code (EFIT) with POINT constraints for the plasma core.

Measurement and simulation of the response function of time of flight enhanced diagnostics neutron spectrometer for beam ion studies at EAST tokamak.

The 2.5 MeV TOFED (Time-Of-Flight Enhanced Diagnostics) neutron spectrometer with a double-ring structure has been installed at Experimental Advanced Superconducting Tokamak (EAST) to perform advanced neutron emission spectroscopy diagnosis of deuterium plasmas. This work describes the response function of the TOFED spectrometer, which is evaluated for the fully assembled instrument in its final layout. Results from Monte Carlo simulations and dedicated experiments with pulsed light sources are presented and used to determine properties of light transport from the scintillator. A GEANT4 model of the TOFED spectrometer was developed to calculate the instrument response matrix. The simulated TOFED response function was successfully benchmarked against measurements of the time-of-flight spectra for quasi-monoenergetic neutrons in the energy range of 1-4 MeV. The results are discussed in relation to the capability of TOFED to perform beam ion studies on EAST.

First results from gamma ray diagnostics in EAST Tokamak.

Gamma ray diagnostics has been developed in the EAST tokamak recently. Six BGO scintillator detectors are arranged on the down-half cross-section and pointed at the up-half cross-section of plasma, with space resolution about 15 cm and energy range from 0.3 MeV to 6 MeV. Three main gamma ray peaks in the energy spectra have been observed and are identified as the results of nuclear reactions 207Pb(n, n')207mPb, H(n, γ) D, and D(p, γ)3He, respectively. Upgrading of the system is in progress by using LaBr3(Ce) scintillator, fast photo-multiplier tubes, and a fully digital data acquisition system based on high sample frequency digitizers with digital pulse processing algorithms.

Status of neutron diagnostics on the experimental advanced superconducting tokamak.

Neutron diagnostics have become a significant means to study energetic particles in high power auxiliary heating plasmas on the Experimental Advanced Superconducting Tokamak (EAST). Several kinds of neutron diagnostic systems have been implemented for time-resolved measurements of D-D neutron flux, fluctuation, emission profile, and spectrum. All detectors have been calibrated in laboratory, and in situ calibration using 252Cf neutron source in EAST is in preparation. A new technology of digitized pulse signal processing is adopted in a wide dynamic range neutron flux monitor, compact recoil proton spectrometer, and time of flight spectrometer. Improvements will be made continuously to the system to achieve better adaptation to the EAST's harsh γ-ray and electro-magnetic radiation environment.