bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhancing quantum metrology for multiple frequencies of oscillating magnetic fields by quantum control
Authors: Lei 雷 Xin 昕 , Fan 范 Jingyi 静怡 , Pang 庞 Shengshi 盛世 
Published: March 2024

Abstract
Quantum multi-parameter estimation has recently attracted increased attention due to its wide applications, with a primary goal of designing high-precision measurement schemes for unknown parameters. While existing research has predominantly concentrated on time-independent Hamiltonians, little has been known about quantum multi-parameter estimation for time-dependent Hamiltonians due to the complexity of quantum dynamics. This work bridges the gap by investigating the precision limit of multi-parameter quantum estimation for a qubit in an oscillating magnetic field model with multiple unknown frequencies. As the well-known quantum Cramér–Rao bound is generally unattainable due to the potential incompatibility between the optimal measurements for different parameters, we use the most informative bound instead which is always attainable and equivalent to the Holevo bound in the asymptotic limit. Moreover, we apply additional Hamiltonian to the system to engineer the dynamics of the qubit. By utilizing the quasi-Newton method, we explore the optimal schemes to attain the highest precision for the unknown frequencies of the magnetic field, including the simultaneous optimization of initial state preparation, the control Hamiltonian and the final measurement. The results indicate that the optimization can yield much higher precisions for the field frequencies than those without the optimizations. Finally, we study the robustness of the optimal control scheme with respect to the fluctuation of the interested frequencies, and the optimized scheme exhibits superior robustness to the scenario without any optimization.
Kinetic plasma-wall interaction using immersed boundary conditions
Authors: Munschy Yann , Bourne Emily , Dif-Pradalier Guilhem , Donnel Peter , Ghendrih Philippe , Grandgirard Virginie , Sarazin Yanick 
Published: March 2024

Abstract
The interaction between a plasma and a solid surface is studied in a (1D-1V) kinetic approach using immersed boundary conditions and penalization to model the wall. Two solutions for the penalized wall region are investigated that either allow currents to flow within the material boundary or not. Essential kinetic aspects of sheath physics are recovered in both cases and their parametric dependencies investigated. Importantly, we show how the two approaches can be reconciled when accounting for relevant kinetic effects. Non-Maxwellian features of the ion and electron distribution functions are essential to capture the value of the potential drop in the sheath. These features lead to a sheath heat transmission factor for ions 60% larger than usually predicted and 35% for electrons. The role of collisions is discussed and means of incorporating minimally-relevant kinetic sheath physics in the gyrokinetic framework are discussed.
Influence of AR injection on shielding layer properties and surface protection from transient high heat loads under the QSPA plasma exposures
Authors: Garkusha I.E. , Makhlai V.A. , Herashchenko S.S. , Ladygina M.S. , Aksenov N.N. , Byrka O.V. , Petrov Yu.V. , Volkova Y.E. , Kulik N.V. , Staltsov V.V. , Yelisyeyev D.V. 
Published: March 2024

Abstract
The paper presents experimental studies of a shielding plasma layer formation in front of a tungsten surface exposed with hydrogen plasma in the QSPA-M test-bed facility under the conditions of additional seeding of argon (Ar) along the target surface into the zone of plasma-surface interaction. A pulsed gas injector on the base of a fast electromagnetic valve has been developed for the local injection of Ar. The injector is capable of generating a homogeneous argon gas flow with a maximum concentration above n
Ar = 6 × 1023 m−3 and a pulse duration of 0.5 ms. It is shown that the increase in the argon gas density in front of the surface leads to an essential decrease (in 1.5–2 times) in the energy load delivered to the target surface. In the presence of a strong magnetic field (up to 1 T), both the thickness of the shielding layer and the fraction of energy dissipated by the shield increase further. Even for moderate energy densities of the QSPA plasma streams in the experiments with Ar gas injection, less than 40% of the impacting plasma load is absorbed by the tungsten surface. The results demonstrate that this additional shielding attributed to the formation of a dense Ar plasma layer in front of the exposed W surface would be favourable for the divertor armour performance, causing the decreasing erosion of plasma-facing components in the course of transient events in a fusion reactor.
Overview of advances in ASDEX Upgrade plasma control to support critical physics research for ITER and beyond
Authors: Kudlacek O. , David P. , Gomez I. , Gräter A. , Sieglin B. , Treutterer W. , Weiland M. , Zehetbauer T. , Van Berkel M. , Bernert M. , Bosman T. , Felici F. , Giannone L. , Illerhaus J. , Kropackova D. , Lang P.T. , Maraschek M. , Ploeckl B. , Reich M. , Vedl Kubincova A. ,   the ASDEX Upgrade Team,   EUROfusion Tokamak Exploitation Team
Published: March 2024

Abstract
The successful operation of fusion reactors requires plasma scenarios with good core confinement and acceptable first wall heat loads that are stable and robust to external perturbations. This poses both physical and technological challenges. One of the technologies that addresses these challenges is a complex feedback control system that supports advances in physical understanding and helps to ensure stable operating conditions. The operation of marginally stable plasmas often leads to off-normal events (such as disruptions) and feedback control can prevent these to some extent. This contribution gives an overview of the main results of the development and operation of the feedback control algorithms on ASDEX Upgrade (AUG). Fueling actuators, using a combination of gas valves and pellet injection, can simultaneously control neutral density of the divertor and the density of the plasma core above the Greenwald limit. Impurity injection is employed to control the position of the X-point radiator, allowing the creation of an ELM-suppressed H-mode with high radiation fraction. Heating actuators are used to control the plasma energy content, which supports advanced tokamak experiments and enables stable I-mode operation, and the electron temperature control, which supports turbulence studies. In control technology, AUG has pioneered the use of virtual actuators, which allow effective use of the limited number of heating actuators, adaptive control policies, and exception handling. Such technologies will also be used in ITER. Advanced nonlinear state observers (RAPTOR, RAPDENS) and codes to evaluate the power deposition properties (RABBIT, TORBEAM) are available for routine use in the AUG feedback controllers. Extensive use of the AUG discharge control system further enhances the research capabilities of this machine.
Numerical research on internal solitary waves in stratified fluid
Authors: Huang Miaomiao , Li Yinghua , Pan Ziying 
Published: March 2024

Abstract
Internal solitary waves are a common nonlinear large amplitude internal wave in nature, which can cause strong divergence and sudden strong currents in seawater during propagation, thus having great destructive effects on marine structures. The paper focuses on numerical wave generation based on three types of internal solitary wave theories. The waves are numerical simulated by RANS method in the paper. The numerical results of internal solitary wave theories are compared and analyzed. It shows that under the same numerical water tank scale and calculation conditions, the mKdV theory can obtain the largest wave amplitude, followed by the eKdV theory and the KdV theory. In addition, background currents will accelerate the propagation speed of internal solitary waves and increase their amplitude slightly.
A Scheme for Credibility of Surface Currents Derived From High Frequency Radars
Authors: Wang Li , Wu Xiongbin , Ai Weihua 
Published: March 2024

Abstract
Large amount of real-time ocean currents measured by HF radar have been included into the ocean observation database in many countries and regions, in support of applications for various marine activities such as marine research, Oil spill detection, tsunami warning, search and rescue. However, due to the performance of inversion algorithms and radar antennas, and other reasons, there are differences in the credibility of ocean current results at different times and locations, which brings on difficulties to applications of ocean currents. This letter proposes a method for developing a credibility model of ocean current results, mainly for all-digital multi-input and multi-output (MIMO) HF radar. By comparing the model with field experimental results, it is confirmed that the method is feasible. It will be very beneficial for radar users to select and use ocean current results, greatly reducing the work of verification of newly installed radars, and will be an innovation in the application technology of over-the-horizon marine radars.
Quality assessment of the mapping of satellite ocean altimeter data
Authors: Lv Xianyu , Ren Kaijun , Liu Lei , Wang Huizan , Bao Senliang , Zhang Xiaoya 
Published: March 2024

Abstract
Based on the orbital data of the Jason3 satellite, the absolute dynamic topography (ADT) of 1/8°×1/8° and 1/4°×1/4° products distributed by AVISO (hereinafter referred to as AVISO1/8° and AVISO1/4°) was interpolated into the Jason3 orbit, and the effective resolution and merged product error of the two products were evaluated with the Northwest Pacific Ocean as the target area. In addition, combined with independent SST data and drifting buoy data, the ground conversion field in the merged data was tested, and the results showed that although the spatial resolution of AVISO1/8° was doubled compared with AVISO1/4°, its effect was not significantly improved, and the error in some areas was even slightly greater than that of AVISO1/4°. Finally, these two merged datasets were used to identify mesoscale vortices. AVISO1/8° have higher precision and make identifying vortex structures easier. The two products are consistent in identifying vortices with relatively large radius, while there are differences in identifying vortices with relatively small radius.
Atmospheric correction based on the optimal solution of aerosol mix ratio: A case study for Pearl River Estuary
Authors: Wu Jie , Chen Chuqun , Shi Jian 
Published: March 2024

Abstract
In ocean color remote sensing, the presence of absorbing aerosols and turbid waters will lead to increased errors in atmospheric correction (AC) for coastal regions. In order to reduce these errors, an alternative AC algorithm has been proposed based on the in situ measurements of the Pearl River Estuary (PRE) and the candidate aerosol models including continental, maritime, and absorbing urban aerosols. The new AC algorithm optimally solved the equation set which is constructed by the multi-spectral relationships of remote sensing reflectance (Rrs
) and the aerosol reflectance of each aerosol model. The performances of the new AC were evaluated using the simulated dataset and the in situ Rrs
. The results indicated that this algorithm can effectively reduce the overestimation of aerosol reflectance caused by absorbing aerosols, and can retrieve reasonable Rrs
values in PRE.
Three DOF Rotation Compensation in Floating HFSWR for Ocean Current Inversion
Authors: Yi Xianzhou 
Published: March 2024

Abstract
High-frequency surface wave radar (HFSWR) has been widely used for ocean surface current inversion. Floating this radar can realize the ocean surface inversion among large areas far away from the coastline. However, six degree-of-freedom (DOF) movements will set the barrier for the ocean current inversion on its radial velocity estimation and direction of arrival estimation. Among these movements, three DOF rotations can cause both Doppler modulation and azimuth modulation while three DOF translations only cause Doppler modulation which is dependent on the arrival direction of echoes. Hence, the analysis and compensation for three DOF rotations are first to be solved. In this paper, we analyse the Doppler modulation and azimuth modulation of three DOF rotations and further develop the global adaptive beamforming method to compensate for these rotations. Adaptive beamforming is used to compensate for rotations to make the real-time beams fixed to the ground when the platform is rotating. Simulations indicate that the global adaptive beamforming can perfectly compensate for the reasonable rotations, among which the yaw rotation is the dominant factor for both Doppler spectrum modulation and azimuth modulation. The rotation compensation using global adaptive beamforming can greatly improve the precision of ocean surface inversion.
Global Sea Surface Temperature Analysis Based on Domestic Ocean Satellite Data. Part I: Methods and Results
Authors: Yu Qinglong , Wan Liying , Qin Yinghao 
Published: March 2024

Abstract
Sea surface temperature is widely used in research and applications such as upper ocean processes, air-sea heat exchange, numerical simulation and prediction of the ocean and atmosphere. In this article, the global gap-free fusion data of sea surface temperature has been developed using optimal interpolation (OI) method which is commonly used by international operational institution, merging satellite remote sensed H1C, H2B, AVHRR, AMSR data and GTS in-situ data. According to three data fusion experiments, it is found that the fusion results of domestic satellite remote sensed data during the test period are qualitatively better than those of foreign satellites in the Northwest Pacific region. Further quantitative analysis is compared with Argo surface SST data, a total of 41842 data pairs are matched in 2022, with a deviation of -0.0756 and a root mean square error of 0.4283.
A Global Coupled Atmosphere-Wave Model System Based on C-Coupler2. Part I: Model Description
Authors: Peng Wei , Zhang Yunfei , Wang Yi , Chen Li , Liu Kewei 
Published: March 2024

Abstract
This study presents a global coupled atmosphere-wave model system (MPAS-NWW3) and its verification. The Community Coupler2 (C-Coupler2), a developed coupler, is used to couple the global wave configuration of the NWW3 (WAVEWATHCH III) with the global atmosphere configuration of the MPAS-Atmosphere model. Surface wind at 10 meters above sea level, temperature and specific humidity at 2 meters above sea level are the coupled variables for atmospheric component model, and significant wave height, average wave length and peak frequency are for wave component model. Some codes are added to the surface layer scheme and the effect of momentum flux induced by sea waves is taken into consideration in this paper. All the coupled variables, input or output the coupler are demonstrated their consistency in the MPAS-NWW3 coupled model.
Removing the systematic errors of the model in operational oceanography forecasting system using data assimilation method
Authors: Zu Ziqing , Zhu Xueming , Ren Shihe , Zhou Qian , Zhang Yunfei , Li Ang , Yang Qing , Li Xiang 
Published: March 2024

Abstract
For the operational oceanography forecast, the synoptic forecast error is partly from the long-term systematic bias of the model, which can be partly counteracted by adjusting the values of the physical parameters. To this end, a four-dimensional optimization system is implemented into the South China Sea operational oceanography forecasting system, to adjust the values of multi-parameters using data assimilation method. By assimilating Argo temperature profiles of 51 days in the model domain, five physical parameters (coefficients of horizontal/vertical diffusion/viscosity and linear bottom drag) of the model have been adjusted simultaneously, and then the optimal values are obtained. The RMSE of temperature simulations in the assimilation window decreases from 1.17 to 0.97 K, when using the optimal values. The validation of the freerun experiments shows that the temperature RMSE decreases from 0.97 to 0.88 K, which indicates that the optimal values are still valid in a longer and independent period. Finally, the validation of the hindcast experiments shows that at the synoptic scale the temperature RMSE decreases from 0.90 to 0.80 K and other variables also present improvements. It hints that it is feasible to reduce the synoptic forecast errors by adjusting the parameter values at the climatological scale to partly counteract the systematic bias of the model. Therefore, it also provides a potential pathway to improve the synoptic forecast skill for the operational oceanography forecasting system.
Numerical Simulation of the Northwest Pacific Based on the MaCOM
Authors: Feng Boyu , Wang Zhaoyi , Zhang Yu , Wan Liying 
Published: March 2024

Abstract
Based on the GLORY reanalysis data, the simulation results of the two versions of MaCOM volume conservation and mass conservation in the Northwest Pacific Ocean for 8 years (1993-2000) are tested. In this paper, the sea surface height, sea surface flow field, sea surface temperature, salinity, vertical profile structures of sea temperature, sea salinity are evaluated respectively. The results show that the average absolute deviation of sea surface temperature is about 0.3 °C, the average absolute deviation of sea surface salinity is about 0.5 psu, the average absolute deviation of sea surface height is about 0.06 m, and the average absolute deviation of see surface current velocity is about 0.08 m/s. Among them, the difference between volume conservation and mass conservation is not large, about from percentile to thousandth percentile. In the vertical direction, the temperature profiles of the two versions are generally consistent, and The maximum deviation from GLORY data is about 0.5°C at depths of 100-400m. In terms of salinity profile, the deviation between the two versions and GLORY mainly exists in the depth range of 200-800 meters, and the deviation is 0.1-0.3 psu. On the whole, MaCOM runs stably and the results are good. It can well reproduce the temperature and salinity characteristics, ocean current field and dynamic environment of the ocean, and is consistent with the internationally recognized high-precision reanalysis data. It is suitable as another powerful tool for studying the ocean.
Spatial-temporal characteristics of temperature in Indonesian Sea based on a high-resolution reanalysis data
Authors: Li Aojie , Zhang Yongchui , Hong Mei , Wang Ning , Hu Wangjiang , Yan Hengqian , Chen Zhentao 
Published: March 2024

Abstract
Influenced by both the Pacific and Indian Oceans, the temperature field in the Indonesian Sea are complicated. In order to reveal the spatial-temporal variability, the surface, thermocline and intermediate layers of the temperature field are studied based on the global ocean reanalysis data of Copernicus Marine Environment Monitoring Service (CMEMS) from 1993 to 2019 and the Empirical Orthogonal Function (EOF) analysis method. The results show that there is a warming trend of 1.36×10−2 °C /year in the surface layer. The first two modes both show reverse changes close to the Pacific and Indian Oceans. The correlation coefficients between the first and second modal time coefficients and the Niño 3.4 index are 0.62 and 0.48, respectively. And the correlation coefficient between the second modal time coefficient and the ITF inflow is -0.45. In the thermocline, there is a warmer trend, which is 4.78×10−2 °C /year. The correlation index of the first and second modal time coefficient with the Niño 3.4 and DMI indices are 0.87 and 0.43, respectively. The correlation index between the first and second modal time coefficient and the ITF inflow are -0.60 and 0.38, respectively. In the intermediate layer, the warming trend is 2.18×10−2 °C /year. From 1993 to 1999, from 2000 to 2016 and from 2017 to 2019, the Sulu Sea and northern Halmahera Sea experienced three periods of warming, cooling and warming, respectively. The study is helpful for further understanding the variation of the temperature field in the Indonesian Sea.
Research on magnetic localization and tracking algorithm based on total magnetic field
Authors: Yi Chuanchuan , Tong Qingshan , Liu Shuang 
Published: March 2024

Abstract
There are few studies on the total magnetic field localization and tracking algorithm based on the domestic magnetic dipole model, and the scalar magnetometer’s measurement of magnetic targets is not affected by its own posture. Therefore, a magnetic localization and tracking algorithm based on the total magnetic field is proposed., this method is based on the magnetic dipole model and uses the particle swarm algorithm and the extended Kalman auxiliary algorithm to achieve magnetic localization and tracking. The effectiveness of this method has been verified through simulation experiments. The relative localization error is small and maintained in the range of about 10%.
Research on the classification of seabed sediments sonar images based on MoCo self-supervised learning
Authors: Yang Y , Wang Y B , Yang Z Y , Yang J , Deng L 
Published: March 2024

Abstract
The discrimination of seafloor substrate type is an extremely important part of seafloor science, and the substrate information is of great significance for the development of marine science and the protection of the marine environment. Current sonar equipment can efficiently generate seafloor images and present seafloor information visually, so the seafloor substrate classification technology based on sonar images has become a hot research topic. Convolutional neural network, as one of the most important classification algorithms in seabed substrate sonar image classification, has excellent performance in most cases. However, the size of the convolutional kernel of convolutional neural network limits the global feature extraction ability, and the ability to discriminate global features in sonar images is weak. In addition, seabed substrate sonar images have labelled data acquisition difficulty and high cost, and acoustic seabed substrate classification in practice generally belongs to small sample classification scenarios. Aiming at the above problems, this thesis selects Swin Transformer, which has strong global feature extraction ability, as the classifier, and uses MoCo self-supervised learning to pre-train the unlabeled data in order to achieve better results.
Research on optimization method of evaporation duct prediction model based on particle swarm algorithm
Authors: Cui Yingxue , Hu Tong , Zhang Cheng , Qiu Zhijin , Zou Jing , Qi Ke , Wang Bo 
Published: March 2024

Abstract
The sea surface roughness parameterization and universal stability functions, as key components of the evaporation duct prediction models rooted in the Monin-Obukhov similarity theory, dictate the model performance which further impacts the efficiency and accuracy of offshore electromagnetic applications. In this paper, layered meteorological and hydrological observations are collected during two cruises and processed to obtain the reference modified refractivity profiles close to the sea surface, and then particle swarm algorithm is utilized to optimize the parameters of the sea surface roughness parameterization and universal stability functions. The results show that compared with the pre-optimization model, the prediction accuracy of the optimized model is improved by 5.09% and 8.12% under stable conditions, and by 9.97% and 31.51% under unstable conditions for observation dataset from each cruise, which proves the feasibility of the proposed method for evaporation duct prediction model optimization.