Nuclear Fusion最新文献_第7页

Simultaneous access to high normalized density, current, pressure, and confinement in strongly-shaped diverted negative triangularity plasmas 在强形分流负三角形等离子体中同时获得高归一化密度、电流、压力和约束性

IF 3.3 1区物理与天体物理

Nuclear Fusion Pub Date : 2024-08-11 DOI: 10.1088/1741-4326/ad69a4

C. Paz-Soldan, C. Chrystal, P. Lunia, A.O. Nelson, K.E. Thome, M.E. Austin, T.B. Cote, A.W. Hyatt, N. Leuthold, A. Marinoni, T.H. Osborne, M. Pharr, O. Sauter, F. Scotti, T.M. Wilks and H.S. Wilson

{"title":"Simultaneous access to high normalized density, current, pressure, and confinement in strongly-shaped diverted negative triangularity plasmas","authors":"C. Paz-Soldan, C. Chrystal, P. Lunia, A.O. Nelson, K.E. Thome, M.E. Austin, T.B. Cote, A.W. Hyatt, N. Leuthold, A. Marinoni, T.H. Osborne, M. Pharr, O. Sauter, F. Scotti, T.M. Wilks and H.S. Wilson","doi":"10.1088/1741-4326/ad69a4","DOIUrl":"https://doi.org/10.1088/1741-4326/ad69a4","url":null,"abstract":"Strongly-shaped diverted negative triangularity (NT) plasmas in the DIII-D tokamak demonstrate simultaneous access to high normalized density, current, pressure, and confinement. NT plasmas are shown to exist across an expansive parameter space compatible with high fusion power production, revealing surprisingly good core stability properties that compare favorably to conventional positive triangularity plasmas in DIII-D. Non-dimensionalizing the key parameters, expanded operating spaces featuring edge safety factors below 3, normalized betas above 3, Greenwald density fractions above 1, and high-confinement mode (H-mode) confinement qualities above 1 are observed, even simultaneously, and all with a robustly stable edge free from deleterious edge-localized mode instabilities. Scaling of the confinement time with engineering parameters reveals at least a linear dependence on plasma current although with significant power degradation, both in excess of expected H-mode scalings. These results increase confidence that NT plasmas are a viable approach to realize fusion power and open directions for future detailed study.","PeriodicalId":19379,"journal":{"name":"Nuclear Fusion","volume":"11 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141945569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Alpha particle loss measurements and analysis in JET DT plasmas JET DT 等离子体中的α粒子损耗测量与分析

IF 3.3 1区物理与天体物理

Nuclear Fusion Pub Date : 2024-08-11 DOI: 10.1088/1741-4326/ad69a1

P.J. Bonofiglo, V.G. Kiptily, J. Rivero-Rodriguez, M. Nocente, M. Podestà, Ž. Štancar, M. Poradzinski, V. Goloborodko, S.E. Sharapov, M. Fitzgerald, R. Dumont, J. Garcia, D. Keeling, D. Frigione, L. Garzotti, F.G. Rimini, D. Van Eester, E. Lerche, M. Maslov and JET Contributors

引用次数: 0

Cluster dynamics modeling of hydrogen retention and desorption in tungsten with saturation and multi-trapping effect of sinks 具有饱和和多捕集效应的钨中氢保留和解吸的簇动力学模型

IF 3.3 1区物理与天体物理

Nuclear Fusion Pub Date : 2024-08-11 DOI: 10.1088/1741-4326/ad6913

Xiaoru Chen, Yuanyuan Zhang, Liuming Wei, Qirong Zheng, Chuanguo Zhang and Yonggang Li

{"title":"Cluster dynamics modeling of hydrogen retention and desorption in tungsten with saturation and multi-trapping effect of sinks","authors":"Xiaoru Chen, Yuanyuan Zhang, Liuming Wei, Qirong Zheng, Chuanguo Zhang and Yonggang Li","doi":"10.1088/1741-4326/ad6913","DOIUrl":"https://doi.org/10.1088/1741-4326/ad6913","url":null,"abstract":"Hydrogen (H) retention and desorption in tungsten (W)-based plasma-facing materials are still not well understood, largely due to the limitations of ex-situ observations in experimental detection methods like thermal desorption spectroscopy (TDS). In order to reveal the fundamental mechanisms behind H retention and desorption, we developed a cluster dynamics model, IRadMat-TDS, for theoretical modeling of depth distribution and TDS of deuterium (D) in polycrystalline W. The model newly includes the saturated absorption and emission of D in inherent sinks like grain boundaries (GBs), as well as the multi-trapping effect of D in various types of GBs with different trapping energies. The simulated TDS spectra are in agreement with experimental ones. For polycrystalline W under D ion irradiation within keV-energy range, two typical thermal desorption peaks in TDS at around 490 and 550 K are explicitly attributed to D emission from GBs and vacancies, respectively. And GBs play a major role in D retention. Moreover, the broad peaks in TDS come from the convolution of multi-trapping of D in sinks with different types of trapping sites rather than a single-site approximation.","PeriodicalId":19379,"journal":{"name":"Nuclear Fusion","volume":"85 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141945545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Global gyrokinetic analysis of Wendelstein 7-X discharge: unveiling the importance of trapped-electron-mode and electron-temperature-gradient turbulence 温德斯坦 7-X 放电的全局陀螺动力学分析：揭示困电子模式和电子温度梯度湍流的重要性

IF 3.3 1区物理与天体物理

Nuclear Fusion Pub Date : 2024-08-11 DOI: 10.1088/1741-4326/ad6675

Felix Wilms, Alejandro Bañón Navarro, Thomas Windisch, Sergey Bozhenkov, Felix Warmer, Golo Fuchert, Oliver Ford, Daihong Zhang, Torsten Stange, Frank Jenko and the W7-X Team

引用次数: 0

Validation of a synthetic fast ion loss detector model for Wendelstein 7-X 温德斯坦 7-X 合成快速离子损耗探测器模型的验证

IF 3.3 1区物理与天体物理

Nuclear Fusion Pub Date : 2024-08-07 DOI: 10.1088/1741-4326/ad6885

A. LeViness, S.A. Lazerson, A. Jansen van Vuuren, J. Rueda-Rueda, M. Beurskens, S. Bozhenkov, K.J. Brunner, O.P. Ford, G. Fuchert, M. Garcìa-Muñoz, M. Isobe, C. Killer, J. Knauer, K. Ogawa, N. Pablant, E. Pasch, P. Poloskei, T. Romba and the W7-X Team

{"title":"Validation of a synthetic fast ion loss detector model for Wendelstein 7-X","authors":"A. LeViness, S.A. Lazerson, A. Jansen van Vuuren, J. Rueda-Rueda, M. Beurskens, S. Bozhenkov, K.J. Brunner, O.P. Ford, G. Fuchert, M. Garcìa-Muñoz, M. Isobe, C. Killer, J. Knauer, K. Ogawa, N. Pablant, E. Pasch, P. Poloskei, T. Romba and the W7-X Team","doi":"10.1088/1741-4326/ad6885","DOIUrl":"https://doi.org/10.1088/1741-4326/ad6885","url":null,"abstract":"We present the first validated synthetic diagnostic for fast ion loss detectors (FILDs) in the Wendelstein 7-X (W7-X) stellarator. This model has been developed on, and validated against experimental data from, a FILD provided by the National Institute for Fusion Science (NIFS-FILD), with potential future applicability to the existing Faraday Cup FILD (FC-FILD) on W7-X as well as the scintillating FILD (S-FILD) currently under development. A workflow combining Monte Carlo codes BEAMS3D and ASCOT5 is used to track fast ions produced by neutral beam injection from the moment of ionization until they are thermalized or lost from the last closed flux surface, and from there to a virtual plane which serves as a projection of the entrance aperture to the FILD. Simulations in ASCOT5 are analyzed via a geometric method to determine the probability of transmission through the FILD aperture and onto the detector as a function of normalized momentum, pitch angle, gyrophase, and position at the virtual plane. This probability is then applied to the simulated ions arriving from the plasma, producing a simulated signal from a computationally tractable number of simulated fast ions. Simulated signals are presented for two W7-X experiments with neutral beam injection and quantitatively compared with experimental measurements from the NIFS-FILD diagnostic. An estimate of the frequency of charge-exchange with neutral particles in the edge is performed, and it is found that this process may have a significant impact on the measured signals.","PeriodicalId":19379,"journal":{"name":"Nuclear Fusion","volume":"93 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141945548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Deconfinement of runaway electrons by local vertical magnetic field perturbation 局部垂直磁场扰动对失控电子的解约束作用

IF 3.3 1区物理与天体物理

Nuclear Fusion Pub Date : 2024-08-01 DOI: 10.1088/1741-4326/ad5a1e

Someswar Dutta, Deepti Sharma, R.L. Tanna, J. Ghosh and D. Raju

{"title":"Deconfinement of runaway electrons by local vertical magnetic field perturbation","authors":"Someswar Dutta, Deepti Sharma, R.L. Tanna, J. Ghosh and D. Raju","doi":"10.1088/1741-4326/ad5a1e","DOIUrl":"https://doi.org/10.1088/1741-4326/ad5a1e","url":null,"abstract":"Runaway electron (RE) deconfinement and subsequent suppression is of prime importance for successful long-term operation of any tokamak. In this work, to deconfine and mitigate REs, the efficacy of local vertical field (LVF) perturbation has been explored numerically. LVF perturbation-assisted RE loss studies are carried out by simulating the drift orbits of the REs in magnetostatic perturbed fields and estimating the resulting orbit losses for different initial energies and magnitudes of LVF perturbation. To this end, the pre-existing PARTICLE code has been extended to the relativistic full-orbit-following code PARTICLE-3D (P3D) integrated with the magnetic field calculation code EFFI and plasma equilibrium field calculation code IPREQ to include the required fields for studying particle dynamics in general; this is then used to numerically model LVF perturbation-assisted RE deconfinement experiments conducted in the ADITYA tokamak. Simulation results show a significant (∼90%) deconfinement of REs with the application of LVF perturbation of a suitable amplitude (∼0.1% of the total magnetic field) in a preferred direction. The existence of a threshold magnitude of the applied field is also established, which is observed to be dependent on the energy of the REs. The simulation results reproduce all the experimental observations and reveal other interesting features of RE mitigation using LVF perturbation. The temporal map of orbiting time of REs shows that REs originating from the inboard side edge region ( N > 0.5) of the plasma are relatively more prone to be lost with the application of suitable LVF perturbation than those originating from the plasma core. Interestingly, the simulation results demonstrate the existence of strong correlation between the safety factor (q) profile in the plasma edge region ( N > 0.7) and the level of RE deconfinement using LVF perturbation.","PeriodicalId":19379,"journal":{"name":"Nuclear Fusion","volume":"219 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141885827","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Development and manufacturing of beryllium-armoring ITER enhanced heat flux FW toward series production in China 在中国开发和制造铍铠装热核聚变实验堆增强热通量 FW，并实现批量生产

IF 3.3 1区物理与天体物理

Nuclear Fusion Pub Date : 2024-07-25 DOI: 10.1088/1741-4326/ad5b04

J.M. Chen, P.H. Wang, Y. Zhou, Q. Li, J.L. Li, J. Wu, J. Du, B. Yang, X.B. Zhu, H. Gao, D. Hu, Y.Y. Chen, Q.M. Wang, Z.H. Liu, K. Wang, S. Liu, L.M. Bao and R. Hunt

{"title":"Development and manufacturing of beryllium-armoring ITER enhanced heat flux FW toward series production in China","authors":"J.M. Chen, P.H. Wang, Y. Zhou, Q. Li, J.L. Li, J. Wu, J. Du, B. Yang, X.B. Zhu, H. Gao, D. Hu, Y.Y. Chen, Q.M. Wang, Z.H. Liu, K. Wang, S. Liu, L.M. Bao and R. Hunt","doi":"10.1088/1741-4326/ad5b04","DOIUrl":"https://doi.org/10.1088/1741-4326/ad5b04","url":null,"abstract":"ITER’s enhanced heat flux (EHF) first wall (FW) provides thermal shielding to the other components behind it and limits its plasma boundary, consequently bearing high surface heat loads up to 4.7 MW m−2. China developed the EHF FW technologies in steady stages by making small mock-ups, semi-prototypes and a full-scale prototype (FSP), working toward series production at the Southwestern Institute of Physics. All the key technologies for bimetallic diffusion bonding, welding and assembly have been fully qualified. The Be armor tile size effects on thermal-fatigue performance have been evaluated using a pulsed high heat flux test with an EMS-400 electron beam facility. It was found that both the Be/CuCrZr bonding and its thermal-fatigue life are highly dependent on the tile size, and 12 × 12 mm2 Be tiles are acceptable for the required performance, either as individual tiles or in castellation by cutting larger ones. Small-scale mock-ups with such Be tiles survived 16 000 thermal cycles at 4.7 MW m−2, while EHF FW fingers with 16 × 16 mm2 Be tiles demonstrated unstable performance. In contrast, only BE tiles larger than 24 × 12 mm2 showed reliable diffusion bonding with the CuCrZr heat sink by hot isostatic pressing and consequently should be castellated into smaller ones. The manufacturing of the FSP finger goes through complex thermal cycles, using CuCrZr alloys in age-strengthening plus cold-rolling states, enabling it to maintain its tensile strength to the level of 285 MPa and its mean grain size less than 100 µm. The pipe welding for finger pairing and its assembly with the central beam are demonstrated, including enabling welding to be carried out twice for repair in a narrow space. The FSP showed good finger alignment, dimensional control and reliable vacuum tightness without any blockage of cooling channels.","PeriodicalId":19379,"journal":{"name":"Nuclear Fusion","volume":"36 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141782321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

High-beta disruption prediction study on HL-2A with instance-based transfer learning 利用基于实例的迁移学习对 HL-2A 进行高比特干扰预测研究

IF 3.3 1区物理与天体物理

Nuclear Fusion Pub Date : 2024-07-25 DOI: 10.1088/1741-4326/ad59b5

Y. Zhong, W. Zheng, Z.Y. Chen, W. Yan, F. Xia, L.M. Yu, F.M. Xue, C.S. Shen, X.K. Ai, Z.Y. Yang, Y.L. Yu, Z.S. Nie, Y.H. Ding, Y.F. Liang, Z.P. Chen and J-TEXT Team

{"title":"High-beta disruption prediction study on HL-2A with instance-based transfer learning","authors":"Y. Zhong, W. Zheng, Z.Y. Chen, W. Yan, F. Xia, L.M. Yu, F.M. Xue, C.S. Shen, X.K. Ai, Z.Y. Yang, Y.L. Yu, Z.S. Nie, Y.H. Ding, Y.F. Liang, Z.P. Chen and J-TEXT Team","doi":"10.1088/1741-4326/ad59b5","DOIUrl":"https://doi.org/10.1088/1741-4326/ad59b5","url":null,"abstract":"Unmitigated disruptions pose a much more serious threat when large-scale tokamaks are operating in the high performance regime. Machine learning based disruption predictors can exhibit impressive performance. However, their effectiveness is based on a substantial amount of training data. In future reactors, obtaining a substantial amount of disruption data in high performance regimes without risking damage to the machine is highly improbable. Using machine learning to develop disruption predictors on data from the low performance regime and transfer them to the high performance regime is an effective solution for a large reactor-sized tokamak like ITER and beyond. In this study, a number of models are trained using different subsets of data from the HL-2A tokamak experiment. A SHapley Additive exPlanations (SHAP) analysis is executed on the models, revealing that there are different, even contradicting, patterns between different performance regimes. Thus, simply mixing data among different performance regimes will not yield optimal results. Based on this analysis, we propose an instance-based transfer learning technique which trains the model using a dataset generated with an optimized strategy. The strategy involves instance and feature selection based on the physics behind differences in high- and low-performance discharges, as revealed by SHAP model analysis. The TrAdaBoost technique significantly improved the model performance from 0.78 BA (balanced accuracy) to 0.86 BA with a few high-performance operation data.","PeriodicalId":19379,"journal":{"name":"Nuclear Fusion","volume":"5 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141782320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Energetic particles transport in constants of motion space due to collisions in tokamak plasmas 托卡马克等离子体中的碰撞导致的高能粒子在运动常数空间中的迁移

IF 3.3 1区物理与天体物理

Nuclear Fusion Pub Date : 2024-07-25 DOI: 10.1088/1741-4326/ad5190

Guo Meng, Philipp Lauber, Zhixin Lu, Andreas Bergmann and Mireille Schneider

引用次数: 0

Refueling of field-reversed configuration core via axial plasmoids injection 通过轴向等离子体注入为场反转构型堆芯补充燃料

IF 3.3 1区物理与天体物理

Nuclear Fusion Pub Date : 2024-07-25 DOI: 10.1088/1741-4326/ad60dc

T. Asai, T. Takahashi, D. Kobayashi, T. Seki, Y. Takeuchi, O. Mitarai, J. Morelli, N. Mizuguchi, S. Dettrick, H. Gota, T. Roche, T. Matsumoto, M. Binderbauer, T. Tajima, M. Inomoto and T. Takahashi

{"title":"Refueling of field-reversed configuration core via axial plasmoids injection","authors":"T. Asai, T. Takahashi, D. Kobayashi, T. Seki, Y. Takeuchi, O. Mitarai, J. Morelli, N. Mizuguchi, S. Dettrick, H. Gota, T. Roche, T. Matsumoto, M. Binderbauer, T. Tajima, M. Inomoto and T. Takahashi","doi":"10.1088/1741-4326/ad60dc","DOIUrl":"https://doi.org/10.1088/1741-4326/ad60dc","url":null,"abstract":"This study successfully developed a refueling technique for a field-reversed configuration (FRC) via axial plasmoid injection and demonstrated it on the FAT-CM device at Nihon University. The target FRC is generated using the collisional-merging formation technique combined with conical theta-pinch formation. Plasmoids with an FRC-like configuration are coaxially injected from both ends of the FAT-CM device toward the preexisting target FRC. Postinjection, the system achieves equilibrium, resulting in increases by factors of 1.8 and 2.4 in the total inventory and plasma energy, respectively, compared to cases without injection. This method effectively accomplishes FRC refueling while preserving the intrinsic characteristics of a simply connected, axisymmetric configuration and a high beta value approaching unity. Therefore, this approach offers potential for repetitive refueling in the reactor stage having a FRC plasma core. Experimental outcomes are compared with magnetohydrodynamic simulation results. In the collisional merging process, the characteristics of the pre-collision plasmoids, such as the strong toroidal rotation and coherent FRC-like magnetic field structures of the FRC, are not preserved. Experimental environments have been constructed to investigate such unique properties of the resulting FRCs.","PeriodicalId":19379,"journal":{"name":"Nuclear Fusion","volume":"71 1","pages":""},"PeriodicalIF":3.3,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141782322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0