Advanced Scenarios Research Articles

Steady-state sustainment of divertor detachment with multi-species impurity seeding in LHD

Multi-species impurity seeding is an advanced operation scenario to mitigate the divertor heat load for the realization of future fusion reactors. In the large helical device, divertor detachment is successfully sustained using higher-Z (krypton, Kr) and lower-Z (neon, Ne) superimposed seeding. Emission from Kr impurities is drastically enhanced if it is followed by Ne seeding. Plasma radiation can be enhanced even at the upstream region in the edge plasma compared with Ne only seeded plasmas with suppression of impurity accumulation toward the central plasma. The characteristics of divertor heat load reduction and energy confinement are comparable between the Kr + Ne seeding and Ne only seeding under the same radiation fraction. However, while the detachment in Ne only seeding is transient, the detachment in Kr + Ne seeding is stable. It indicates that multi-species impurity seeding can be competitive for steady-state operation although further investigation is desired about the balance between divertor heat load reduction, impurity screening, and confinement degradation. The Kr emission enhancement is strongly affected by electron density and temperature at the last closed flux surface resulting in impurity penetration.

Robust real-time feedback algorithms for plasma kinetic control in advanced tokamak scenarios

Robust real-time control algorithms for tracking plasma kinetic parameters in advanced tokamak scenarios are developed based on linear state-space (LSS) dynamic models. The real-time control algorithms under study comprise the robust control, the linear quadratic integral control and the internal model control. The plasma models used in this work are restricted to LSS models identified from dedicated simulation/experimental data, though the proposed control algorithms can conveniently be extrapolated to broadly incorporate linear models obtained from first-principles plasma theory. The control objective is to track plasma kinetic parameters of interest to desired operating points in advanced tokamak scenarios by actuating additional heating & current drive systems in real-time. Plasma kinetic parameters involve the poloidal pressure parameter β p , the internal inductance , the average toroidal rotation angular speed and the electron temperature on axis while the actuators are the ion cyclotron resonance heating and lower hybrid current drive systems. In order to achieve enhanced control performance, two control layers are designed. The outer layer, i.e. an internal model-based proportional-integral actuator controller, operating on a fast timescale ( the energy confinement time τ E ) aiming at tracking the commands requested by the inner kinetic controllers, while the inner layer, i.e. a kinetic controller chosen from various alternatives, running on a slow timescale () is dedicated to tailoring plasma kinetic parameters. Simulation results for the experimental advanced superconducting tokamak (EAST) tokamak are provided and compared to show the capabilities of each control approach. Dedicated kinetic control experiments conducted in an H-mode scenario on EAST are reported as well. The advantages and limits of these control algorithms are discussed and summarised.

Interpretation of electromagnetic modes in the sub-TAE frequency range in JET plasmas with elevated monotonic q-profiles

Recent JET deuterium experiments with an advanced tokamak scenario using an internal transport barrier (ITB) have been performed to clearly observe destabilized toroidicity-induced Alfvén eigenmodes (TAEs) by fast ions; interestingly, these also exhibit unstable electromagnetic (EM) perturbations in the sub-TAE frequency range. We identify such EM perturbations to be beta-induced ion temperature gradient (BTG) eigenmodes and not beta-induced Alfvén eigenmodes nor beta-induced Alfvén acoustic eigenmodes, which are often unstable in such high-beta plasmas with high-power neutral beam injection (NBI). The BTG modes are the most unstable modes due to the high thermal ion temperature gradient related to the ITB, high thermal ion temperature compared to thermal electron temperature (high Ti/Te), and a high ion beta regime. BTG mode experimental characteristics match the analytical theory, i.e., location in the vicinity of a rational magnetic surface with a low magnetic shear, mode frequency scaling with the ion diamagnetic frequency ( ωi*), and a coupling among Alfvén and drift waves. We also perform linear gyrokinetic simulations with validated plasma profiles and equilibrium, and find a mode kinetically driven by thermal ions with similar characteristics as the experimental BTG modes.

Preliminary design of real-time plasma control system for CFETR

The China Fusion Engineering Test Reactor (CFETR), aiming at demonstrating fusion energy production in self-sufficient burning in different advanced operation scenarios, has entered the stage of engineering design and R&D (research and development). The real-time plasma control system (PCS), as a critical system controlling the evolution of plasma parameters that are necessary to operate CFETR, is designed synchronously. The CFETR PCS is composed of system architecture, integrated control algorithms, and two assistant tools PCS-SDP (Software Development Platform) and PCS-VP (Verification Platform) for algorithm development and verification. Taking the steady-state operation and machine safety into account, the requirement and conceptual design of the system architecture of CFETR PCS is introduced in this paper. PCS-SDP, a visual algorithm development platform, has completed the preliminary design and a prototype has been built to validate the design and technical feasibility with the control algorithm development for EAST. PCS-VP is under preliminary design taking ITER PCSSP (Plasma Simulation Platform) design as reference. These two tool platforms will strongly support and accelerate the development of CFETR PCS.

Highly coherent illumination for imaging through opacity

Imaging through opacity has captured extensive attention in recent years for its promising applications in bioimaging systems and information extraction from scrambled light. Many optimized image reconstruction algorithms and advanced imaging scenarios are introduced and intensively studied in previous researches. However, intensity-based image reconstruction under the highly coherent light illumination is still a major challenge due to the strong interference effect. Here, we demonstrate that imaging through opacity can be implemented efficiently even under the highly coherent illumination with the aid of an intensity-based/incoherent deconvolution algorithm. Based on the experimental and theoretical analysis, we find the small phase correlation length of the diffuser plays a pivotal role in enabling the incoherent deconvolution operation for highly coherent illumination. Furthermore, the deconvolution algorithm shows insensitivity to the light coherence since the spatial frequencies of the object are well preserved in the spatial frequency spectrum of the speckle pattern. Our results provide a phase-information-free scheme for imaging through opacity under the highly coherent illumination. We anticipate our work would motivate the deep understanding of imaging using highly coherent illumination, increase the structural robustness of imaging systems and facilitate wavelength-sensitive imaging applications.

Comparison of Estrogenic, Spectroscopic, and Toxicological Analyses of Pilot-Scale Water, Wastewaters, and Processed Wastewaters at Select Military Installations.

Reuse of water requires the removal of contaminants to ensure human health. We report the relative estrogenic activity (REA) of reuse treatment design scenarios for water, wastewaters, and processed wastewaters before and after pilot-scale treatment systems tested at select military facilities. The comparative relationships between REA, several composite toxicological endpoints, and spectroscopic indicators were evaluated for different reuse treatment trains. Four treatment processes including conventional and advanced treatments reduced the estrogenicity by at least 33%. Biologically based methods reduced estrogenicity to below detection levels. Conventional treatment scenarios led to significantly less reduction of adverse biological endpoints compared to the advanced treatment scenarios. Incorporating the anaerobic membrane bioreactor reduced more endpoints with higher reduction percentages compared to the sequencing batch reactor design. Membrane technology and advanced oxidation generated reductions across all biological endpoints, from 65% (genotoxicity) to 100% (estrogenicity). The design scenarios featuring a low-cutoff mechanical screen filter, intermittent activated carbon biofilter, and membrane filtration achieved the highest percent reduction and produced water with the lowest negative biological endpoints. Spectroscopic indicators demonstrated case-specific relationships with estrogenicity and toxicity. Estrogenicity consistently correlated with cytotoxicity and thiol reactivity, indicating the potential for preliminary estrogenicity screening using thiol reactivity.

Conceptual design of Thomson scattering diagnostics for the COMPASS-U tokamak.

The Thomson scattering (TS) diagnostic, one of the key diagnostics used on the tokamaks around the world, is planned for the COMPASS-U tokamak, which is recently under design and construction in the Institute of Plasma Physics in Prague, Czech Republic. This tokamak is supposed to be a world-unique, high magnetic field device with hot walls, allowing for the study of the plasma exhaust in advanced operational scenarios and testing cutting-edge technologies relevant to future fusion reactors, e.g., use of liquid metals. The core and edge TS systems are planned to be designed and operational, with a limited performance, already in the early stage of the tokamak operation. In this contribution, requirements and the most important constraints defining the TS system design are presented. The impact of both the possible collection lens location and spatial resolution on the plasma pedestal observation is simulated. Design considerations also take into account the high-resolution TS core and edge systems available from the COMPASS tokamak, which will be reused. The collection lenses will be newly built. Extension of the detection system will complete the plasma radius coverage in the future. The divertor TS is considered for later periods.

Recent results of fusion triple product on EAST tokamak

High fusion triple product has been obtained in the advanced scenarios with high normalized beta (β N) on the Experimental Advanced Superconducting Tokamak (EAST). A record value of n i0 T i0 τ E ∼ 1.0 × 1019 m−3 keV s for EAST deuterium plasma has been achieved, which is due to the formation of strong and broad internal transport barriers (ITBs) in n e, T e and T i profiles. Analysis shows that the strong ITB formation could be attributed to the reduction of transport from ITG modes. Based on the analysis, the physical mechanisms and methods to further improve the plasma performance are discussed.

Methods for Analyzing the Impact of Transformational Processes on the Right to Develop the Socioeconomic System in the Context of Digitalization: Scenario Approach (Problem Statement)

The article discusses methodological problems behind increasing the efficient transformation of law in a developed information society and assessing their impact on the processes of socioeconomic development of the state and society. Methods and technologies of analysis and management of the development of complex socioeconomic systems are considered. To solve methodological and practical problems of increasing the efficiency of legislative regulation in the context of digitalization, it is proposed to use the scenario analysis methodology, which provides an opportunity for intellectual support and assessment of the quality of preparation and implementation of decisions in the field of legislative activity. The approach proposed for solving the problems under consideration is based on advanced scenario analysis and modeling of the development processes of situations in the political-legal, sociopolitical, socioeconomind innovation-technological spheres. This will allow us to work out alternative options for the development of the law enforcement situation, for which, in general, information is incomplete and there is a high level of uncertainty in its development. The authors have formulated promising directions for future theoretical and applied research within the framework of the development of the methodology of scenario analysis of social and economic reality, as regulated by the rules of law.

Benchmark of quasi-linear models against gyrokinetic single scale simulations in deuterium and tritium plasmas for a JET high beta hybrid discharge

A benchmark of the reduced quasi-linear models QuaLiKiz and TGLF with GENE gyrokinetic simulations has been performed for parameters corresponding to a JET high performance hybrid pulse in deuterium. Given the importance of the study of such advanced scenarios in view of ITER and DEMO operations, the dependence of the transport on the ion isotope mass has also been assessed, by repeating the benchmark changing the ion isotope to tritium. TGLF agrees better with GENE on the linear spectra and the flux levels. However, concerning the isotope dependence, only QuaLiKiz reproduces the GENE radial trend of a basically gyro-Bohm (gB) scaling at inner radii and instead anti-gB at outer radii. The physics effects which are responsible of the antigB effect in GENE simulations have been singled out.

Impact of dendritic cell vaccines added to neoadjuvant CT on pathological complete responses in early breast cancer patients according to PD-L1 expression.

585 Background: Breast cancer (BC) in early stages exhibit a naïve and competent immune system that translates into a more prominent TIL infiltration and higher PD-L1 expression as compared to the advanced BC scenario were immunoescape and exhaustion are more prevalent. Expression of PD-L1 has been related to a better pCR when immune checkpoint inhibitors (IPI) have been added to neaodjuvant chemotherapy (NACT) in triple negative BC (TNBC). Our prior results shown dendritic cells vaccines (DCV) increased pCR in both TNBC and luminal B subtypes, with an absolute gain of 20% (p = 0.03) and a safe tolerance. Methods: Eighty-three HER2 negative BC patients with untreated stage II-III were included: 39 patients from the NCT01431196 trial that combine NACT with autologous DCV and 44 patients from a historic control group treated with the same NACT alone. NACT consists of dose dense Epirubicin plus Cyclophosphamide for 4 cycles sequenced to Docetaxel for 4 cycles. PD-L1 expression was measured in the membrane of tumoral cells with monoclonal rabbit anti PD-L1 28.8 pharmaDX (DAKO, Agilent Technologies) in FFPE samples at diagnosis. Primary endpoint was pathologic complete response (pCR) stratified by PD-L1 expression (positive or negative), while secondary endpoints were event-free survival (EFS) and overall survival (OS), also stratified by PD-L1 expression. Results: Both cohorts were well balanced in most of the features. Thirty-three percent of the tumors in the experimental group were PD-L1 positive, whereas 50% of them in the CG expressed PD-L1 (p = 0.06). Pathological CR was observed in 50% of the PD-L1 positive population, in contrast to a 2.8% in the PD-L1 negative in the NACT cohort (p < 0.01) as compared to the patients assigned to the DCV group (33.4% in PD-L1 positive vs 23.1% in PD-L1 negative population; p = 0.16). Among PD-L1 positive population, more pCR were seen in the CG than in the DCV group (50% vs 33.4%; p = 0.06). Within the PD-L1 negative population, more pCR were observed in the DCV group than in the CG (23.1% vs 2.8%; p < 0.05). With a median follow-up of 7 years, no significant differences were observed between the different subgroups neither in EFS (HR = 1.7; 0.42-6.8; p = 0.19) nor in OS (HR = 2.5; 0.56-11, p = 0.43). At 7 years, 20% and 14.4% of the patients relapsed according to the PD-L1 positive versus negative status respectively, and 10.78% versus 13.33% were dead. Conclusions: The benefit of DCV seems to be outstanding in the PD-L1 negative tumors that have a basal immune appropriate milieu. PD-L1 expression implies a more suppressed niche in which DCV are not able to stimulate antigen presentation and cell cytotoxic activity. PD-L1 positive population reach higher responses with both NACT±DCV than PD-L1 negative group, although the benefit seem to be higher in the NACT alone cohort. Further studies combining DVC+IPI together with NACT are needed. Clinical trial information: NCT01431196.

Frequency-Domain Signal Processing for Spectrally-Enhanced CP-OFDM Waveforms in 5G New Radio

Orthogonal frequency-division multiplexing (OFDM) has been selected as the basis for the fifth-generation new radio (5G NR) waveform developments. However, effective signal processing tools are needed for enhancing the OFDM spectrum in various advanced transmission scenarios. In earlier work, we have shown that fast-convolution (FC) processing is a very flexible and efficient tool for filtered-OFDM signal generation and receiver-side subband filtering, e.g., for the mixed-numerology scenarios of the 5G NR. FC filtering approximates linear convolution through effective fast Fourier transform (FFT)-based circular convolutions using partly overlapping processing blocks. However, with the continuous overlap-and-save and overlap-and-add processing models with fixed block-size and fixed overlap, the FC-processing blocks cannot be aligned with all OFDM symbols of a transmission frame. Furthermore, 5G NR numerology does not allow to use transform lengths shorter than 128 because this would lead to non-integer cyclic prefix (CP) lengths. In this article, we present new FC-processing schemes which solve or avoid the mentioned limitations. These schemes are based on dynamically adjusting the overlap periods and extrapolating the CP samples, which make it possible to align the FC blocks with each OFDM symbol, even in case of variable CP lengths. This reduces complexity and latency, e.g., in mini-slot transmissions and, as an example, allows to use 16-point transforms in case of a 12-subcarrier-wide subband allocation, greatly reducing the implementation complexity. On the receiver side, the proposed scheme makes it possible to effectively combine cascaded inverse and forward FFT units in FC-filtered OFDM processing. Transform decomposition is used to simplify these computations, leading to significantly reduced implementation complexity in various transmission scenarios. A very extensive set of numerical results is also provided, in terms of the radio-link performance and associated processing complexity.

Prediction of high-performance scenario with localized magnetic shear reversal on EAST tokamak

An advanced scenario with high poloidal beta, large-radius internal transport barriers (ITBs) and localized reversed-shear q-profile, has been demonstrated in DIII-D/EAST joint experiments recently on the DIII-D tokamak. This scenario is also one of the future explorations on EAST. In this article, integrated modeling has been utilized to explore the regime with localized reversed-shear q-profile and high performance based on the developed long-pulse scenario on EAST. A scenario with a strong reversed-shear q-profile has been achieved with the combination of 2 MW off-axis ECH, 2.6 MW LHW and 2 MW NBI (H98y2 ∼ 1.35, ∼ 2.56, ∼ 2.23, ). In addition, a small amount (∼0.1 MW) of centrally deposited ECH facilitates the generation of the bootstrap current on or near the axis, and hence reduces the level of the q-profile in this region; thus, a scenario with localized magnetic shear reversal and strong large-radius ITBs is obtained (H98y2 ∼ 1.4, ∼ 2.66, ∼ 2.31, ). Modeling predictions indicate that off-axis ECH/LHW and high plasma density promote the formation of large-radius ITBs. A further increase in the injected power of centrally deposited ECH (0.15 MW) or NBI (4 MW) leads to an increase in the temperature gradient, especially the electron temperature near the axis, and large-radius ITBs disappear in all channels (T e, T i, n e); also, the confinement quality decreases. The bootstrap current density profiles and LHW-driven current profiles tend to peak near the axis due to the increase in electron temperature profiles, which eventually leads to peaked total current profiles, similar to the EAST long-pulse scenario. Changes in magnetic shear result in the disappearance of large-radius ITBs. Modeling validation will be carried out in the near future on the EAST tokamak.

Applications of information channels to physics-informed neural networks for WiFi signal propagation simulation at the edge of the industrial internet of things

The ubiquitous presence of data driven technologies that move information from the edge of the Industrial Internet of Things (IIoT) to the cloud for advanced computation and back to the edge for action are pushing wireless connections to the limit. Under these conditions optimizing WIFI Received Signal Strength Intensity (RSSI) can improve data management, computational workflows, and geolocation accuracy while reducing energy consumption in order to minimize charging and computational resource requirements at the edge. Ensuring connectivity for these mission critical processes will require detailed knowledge (either measured or simulated) of the state of the electromagnetic fields in advanced manufacturing scenarios. Simulation has the advantage of developing more scalable solutions to this characterization problem but comes at a very high computational cost that may not be possible on edge devices with limited computational resources. In order to reduce the time and resource cost of achieving real time simulations with low computing specification edge devices, we propose creating a novel method that exploits the notion of information channels to create efficient Convolutional Neural Networks (CNNs) capable of determining the RSSI given a completely new geometry (never used in training) where objects or obstacles (walls, machines, tables, etc.) and their respective location, size and reflectivity indices, along with the antenna location are completely random.

Beyond copy number: A new, rapid, and versatile method for sequencing the entire SMN2 gene in SMA patients.

Spinal muscular atrophy (SMA) is caused by bi‐allelic loss or pathogenic variants in the SMN1 gene. SMN2, the highly homologous copy of SMN1, is considered the major phenotypic modifier of the disease. Determination of SMN2 copy number is essential to establish robust genotype–phenotype correlations and predict disease evolution, to stratify patients for clinical trials, as well as to define those eligible for treatment. Discordant genotype–phenotype correlations are not uncommon in SMA, some of which are due to intragenic SMN2 variants that may influence the amount of complete SMN transcripts and, therefore, of full‐length SMN protein. Detection of these variants is crucial to predict SMA phenotypes in the present scenario of therapeutic advances and with the perspective of SMA neonatal screening and early diagnosis to start treatments. Here, we present a novel, affordable, and versatile method for complete sequencing of the SMN2 gene based on long‐range polymerase chain reaction and next‐generation sequencing. The method was validated by analyzing samples from 53 SMA patients who lack SMN1, allowing to characterize paralogous, rare variants, and single‐nucleotide polymorphisms of SMN2 as well as SMN2–SMN1 hybrid genes. The method identifies partial deletions and can be adapted to determine rare pathogenic variants in patients with at least one SMN1 copy.

Estimating Operational Benefits of Air Traffic Management Harmonization in the Caribbean Oceanic Airspace

The Caribbean airspace is an operationally complex area because it consists of multiple regions operating under different air navigation service providers with distinct air traffic performance capabilities. This study evaluates the benefits of implementing the Space-Based Automatic Dependent Surveillance-Broadcast technology coupled with reduced and harmonized separation standards in the Caribbean airspace. The operational benefits of using advanced air traffic management procedures are investigated in terms of efficiency, capacity, and air traffic controllers’ taskload with computer simulations. Four scenarios are proposed in this paper, and flight operations with real-scale traffic volumes (low, medium, and high) were simulated. The results show that reducing separation minima in the Caribbean region without considering hemispherical rules provides average savings of 162 kg of fuel and 512 kg of carbon dioxide per flight. The estimated fuel saving could reach 180 million kg or 72 million dollars annually with the current aircraft fleet mix. This study demonstrates that employing advanced surveillance technologies increases the Caribbean airspace capacity and enables commercial flights to cruise at higher flight levels. Furthermore, the total number of tactical resolution maneuvers and the potential air traffic controllers’ taskload reduce in the proposed advanced air traffic scenarios.

Finite-word-length FPGA implementation of model predictive control for ITER resistive wall mode control

In advanced tokamak scenarios, active feedback control of unstable resistive wall modes (RWM) may be required. A RWM is an instability due to plasma kink at higher plasma pressure, moderated by the presence of a resistive wall surrounding the plasma. We address the dominant kink instability associated with the main non-axisymmetric (n = 1) RWM, described by the CarMa model. Model predictive control (MPC) is used, with the aim of enlarging the domain of attraction of the unstable RWM modes subject to power-supply voltage constraints. The implementation of MPC is challenging, because the related quadratic programming (QP) on-line optimization problems must be solved at a sub-ms sampling rate. Using complexity-reduction pre-processing techniques and a primal fast gradient method (FGM) QP solver, sufficiently short computation times for ITER are reachable using a standard personal computer (PC). In this work we explore even faster finite-word-length (FWL) implementation using field-programmable gate arrays (FPGA), which would facilitate experimental testing of such control algorithms on dynamically faster medium-sized tokamaks, and compare the computational accuracy and time with the PC implementation.

Active control of electron cyclotron emission radiometer channel frequencies for improved electron temperature measurements.

As advanced scenarios are developed for tokamak operations, the demand for flexibility of the electron cyclotron emission (ECE) channels' locations has increased. The tunable feature of yttrium iron garnet (YIG) filters provides this spatial flexibility. Here, we present a method of performing ECE measurements on fixed flux surfaces instead of fixed frequencies. This is achieved by adjusting YIG filters utilized in the intermediate frequency section to frequencies associated with flux surfaces in regions of interest during the discharge. The key components are the application of tunable YIG filters and a control program that calculates the filter settings using flux information from real-time reconstruction equilibria (EFIT). This fast procedure facilitates Te measurements in regions of interest to investigate plasma dynamic behaviors.

Resource-Aware Detection and Defense System against Multi-Type Attacks in the Cloud: Repeated Bayesian Stackelberg Game

Cloud-based systems are subject to various attack types launched by Virtual Machines (VMs) manipulated by attackers having different goals and skills. The existing detection and defense mechanisms might be suitable for simple attack environments but become ineffective when the system faces advanced attack scenarios wherein simultaneous attacks of different types are involved. This is because these mechanisms overlook the attackers’ strategies in the detection system’s design, ignore the system’s resource constraints, and lack sufficient knowledge about the attackers’ types and abilities. To address these shortcomings, we propose a repeated Bayesian Stackelberg game consisting of the following phases: risk assessment framework that identifies the VMs’ risk levels, live-migration-based defense mechanism that protects services from being successful targets for attackers, machine-learning-based technique that collects malicious data from VMs using honeypots and employs one-class Support Vector Machine to learn the attackers’ types distributions, and resource-aware Bayesian Stackelberg game that provides the hypervisor with the detection load’s optimal distribution over VMs that maximizes the detection of multi-type attacks. Experiments conducted using Amazon’s datacenter and Amazon Web Services honeypot data reveal that our solution maximizes the detection, minimizes the number of attacked services, and runs efficiently compared to the state-of-the-art detection and defense strategies, namely Collabra , probabilistic migration, Stackelberg, maxmin, and fair allocation.

Safety and efficacy of immune checkpoint inhibitors in non-small-cell lung cancer: focus on challenging populations.

In recent years, immune-checkpoint inhibitors (ICIs) have represented one of the major breakthroughs in advanced non-small cell lung cancer treatment scenario. However, enrollment in registering clinical trials is usually restricted, since frail patients (i.e., elderly, individuals with poor performance status and/or active brain metastases), as well as patients with chronic infections or who take concurrent medications, such as steroids, are routinely excluded. Thus, safety and efficacy of ICIs for these subgroups have not been adequately assessed in clinical trials, although these populations often occur in clinical practice. We reviewed the available data regarding the use of ICIs in these 'special' populations, including a focus on the issues raised by the administration of immunotherapy in lung cancer patients infected with Sars-Cov-2.