Journal of Fusion Energy最新文献

{"title":"Evaluation of Tokamak MHD Instabilities by Instability Indices Investigating Such as Entropy","authors":"H. Mehrniya,&nbsp;M. K. Salem,&nbsp;A. Salar Elahi","doi":"10.1007/s10894-022-00330-y","DOIUrl":"10.1007/s10894-022-00330-y","url":null,"abstract":"<div><p>To investigate the fluctuations of the Mirnov coils magnetic field in tokamak plasma, it is required to assess the spatiotemporal signals. Spatial structure and time evolution related to MHD instabilities in a tokamak can be shown by analyzing the signals from an array of Mirnov coils using the biorthogonal decomposition (BD) method. In this paper by Using this method, the presence of instability modes indices in tokamak IR-T1 namely, singular values entropy and the relative squared magnitude of the first two pairs of the principal axes were calculated and studied. Also, the behavior of indices was also evaluated with and without resonance helical magnetic field (RHF). In this research, the effect of the L = 3/n = 1 and L = 2/n = 1 RHF was examined on the amplification and suppression of MHD activities along with the modification of MHD modes number and the behavior of singular values entropy extraction from BD. We show that, MHD activities mode numbers altered due to the application of RHF or even some MHD modes may be suppressed or amplified. The behavior of P1 and P2 and their temporal dependence and their rate of change will also be investigated under the RHF field. The calculation of singular values entropy of the extraction energy using the BD biorthogonal decomposition method is an important index since the MHD activities in most tokamaks have several MHD modes. The result show that, the entropy of the system increases during MHD activities. The entropy value in IR-T1 tokamak plasma depends on the number of the non-zero singular values extracted from Mirnov fluctuations analysis by biorthogonal decomposition. The results indicate that the very lower number of non-zero eigenvalues will lead to a lower entropy compared to the condition that the number of non-zero eigenvalues is more. It is also expected to identify the MHD activities and mode number and their frequency with other diagnostic tools by observing the changes of entropy. Observing the entropy behavior depends on the tokamak aspects and tokamak plasma parameters. It demonstrates the existence of MHD activities with different frequencies and wavelengths.</p></div>","PeriodicalId":634,"journal":{"name":"Journal of Fusion Energy","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41598628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PMT Signal Transmission for Hard X-Ray Diagnostics of Future Tokamaks","authors":"P. Nowak vel Nowakowski,&nbsp;D. Makowski,&nbsp;W. Walewski","doi":"10.1007/s10894-022-00334-8","DOIUrl":"10.1007/s10894-022-00334-8","url":null,"abstract":"<div><p>A pair of a scintillator and a Photomultiplier Tube (PMT) is often used as a Hard X-Ray (HXR) radiation detector in existing tokamaks such as JET, EAST, COMPASS or ASDEX-U. Future nuclear fusion reactors such as ITER or DEMO will use more powerful magnets and confine a larger volume of hot plasma. Placement of the detectors used for plasma diagnostic will be constrained by high temperatures, magnetic fields and ionizing radiation present near the tokamak vessel. It might be necessary to move detectors away from tokamak to a safer location. This might generate problems with pulse discrimination and transmission of the signal. In the case of the ITER tokamak, sensitive electronics such as digitizers cannot be installed close to the reactor due to harsh environmental conditions. A new approach to component placement is needed to protect those devices. The PMT signal will be transmitted via an over 100 m long coaxial cable to the digitizer located in the adjacent diagnostic building. The long cables will introduce additional signal attenuation. Also, the RF noise from the tokamak environment can couple into the signal. To improve the signal-to-noise ratio a dedicated PMT amplifier with a high output range (from + 1.5 to − 11 V) was proposed.The paper presents issues with signal transmission in HXR diagnostic systems and includes a discussion on the methodology of PMT signal transmission in the conditions of the future tokamaks. A proposal of guidelines for selection of the signal chain components and design of a dedicated PMT amplifier is part of this paper.</p></div>","PeriodicalId":634,"journal":{"name":"Journal of Fusion Energy","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10894-022-00334-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49444148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetohydrodynamic Mode Identification for Golem Mirnov Coil Signals Using Singular Value Decomposition and Multichannel Variational Mode Decomposition Method for Analyzing Time–Frequency","authors":"Jayakumar Chandrasekaran,&nbsp;Sangeetha Jayaraman","doi":"10.1007/s10894-022-00329-5","DOIUrl":"10.1007/s10894-022-00329-5","url":null,"abstract":"<div><p>In this paper, we have investigated the method to study non-stationary signal characteristics in plasma tokamak using the combination of Multichannel Variational Mode Decomposition (MVMD) and Singular Value Decomposition (SVD). We have applied this technique directly without any signal preprocessing techniques over the Mirnov coil signals to analyze the magnetic fluctuations produced by the rotating magnetic fields of the plasma in tokamaks. Extraction of Principal axes (PA) and Principal Components (PC) of multichannel Mirnov coil signals are through the singular value decomposition technique. The Multichannel variational mode decomposition technique is provided with a PC matrix to identify the dominant harmonics as K-modes. Finally, the Time–frequency analysis is carried out using Hilbert Transform (HT). The proposed technique handles multichannel Mirnov coil signals in parallel to frequency identification, and also to understand the poloidal structure during current perturbation. Artificially simulated data and Mirnov coil signals from Golem Tokamak aided in testing the proposed technique. In Golem data during the present rise phase, transition happens in the current perturbation from m = 4, poloidal structures to m = 3, and m = 2. The simulated data and Golem tokamak data generated the results of the proposed model. The article also compared this with other existing signal decomposition techniques.</p></div>","PeriodicalId":634,"journal":{"name":"Journal of Fusion Energy","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43590709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modelling of Neutron Markers for the COMPASS Upgrade Tokamak and Generation of Synthetic Neutron Spectra","authors":"Fabien Jaulmes,&nbsp;Ondrej Ficker,&nbsp;Vladimir Weinzettl,&nbsp;Michael Komm,&nbsp;Ondrej Grover,&nbsp;Jakub Seidl,&nbsp;Georgiy Zadvitskiy,&nbsp;Eva Macusova,&nbsp;Radomir Panek","doi":"10.1007/s10894-022-00328-6","DOIUrl":"10.1007/s10894-022-00328-6","url":null,"abstract":"<div><p>In the future COMPASS Upgrade (Vondracek et al. in Fusion Eng Des 169:112490, https://doi.org/10.1016/j.fusengdes.2021.112490, 2021) tokamak (<span>(R_0 = 0.894, mathrm {m})</span>, <span>(B_t sim 5, mathrm {T})</span>), three distinct types of edge transport barrier are anticipated: ELMy H-mode, EDA H-mode and I-mode. The main auxiliary heating system used to access H-mode will be Neutral Beam Injection (NBI) power. The NBI will have a nominal injection energy of <span>(80,mathrm {keV})</span> at a maximum injection radius <span>(R_{mathrm {tan}} = 0.6, mathrm {m})</span>. A significant neutron yield will occur from the interaction of the beam with the plasma background. Using our orbit-following code EBdyna (Jaulmes et al. in Nucl Fusion 61, 046012, https://doi.org/10.1088/1741-4326/abd41b, 2021), we calculate the trajectories of the NBI ions during the complete thermalization process, calculate the amount of NBI ions losses and evaluate the neutron rate in steady state from the beam–plasma and beam–beam interaction. Combining it with the thermal yield, we can derive detailed synthetic spectrogram of the energy distribution of the neutrons. The markers can be further used to provide synthetic neutron spectrometer diagnostics data. Due to the reduction of the simulated neutron count seen by the detectors when the peaking of the neutron source is lower, we anticipate the need for absolute-calibration in order to recover quantitative results.</p></div>","PeriodicalId":634,"journal":{"name":"Journal of Fusion Energy","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42512130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Plasma Production in ICRF in the Uragan-2M Stellarator in Hydrogen–Helium Gas Mixture","authors":"V. E. Moiseenko,&nbsp;Yu. V. Kovtun,&nbsp;A. V. Lozin,&nbsp;R. O. Pavlichenko,&nbsp;A. N. Shapoval,&nbsp;L. I. Grigor’eva,&nbsp;M. M. Kozulya,&nbsp;S. M. Maznichenko,&nbsp;V. B. Korovin,&nbsp;E. D. Kramskoy,&nbsp;N. V. Zamanov,&nbsp;Y. V. Siusko,&nbsp;D. I. Baron,&nbsp;A. Yu. Krasiuk,&nbsp;V. S. Romanov,&nbsp;I. E. Garkusha,&nbsp;T. Wauters,&nbsp;A. Alonso,&nbsp;R. Brakel,&nbsp;A. Dinklage,&nbsp;D. Hartmann,&nbsp;Ye. Kazakov,&nbsp;H. Laqua,&nbsp;J. Ongena,&nbsp;T. Stange","doi":"10.1007/s10894-022-00326-8","DOIUrl":"10.1007/s10894-022-00326-8","url":null,"abstract":"<div><p>Plasma production experiments in helium at Uragan-2M have been performed to investigate the role of the hydrogen minority in helium. The experiments presented here were carried on with a controlled minority hydrogen concentration. The hydrogen minority allowed one to increase plasma density more than three times as compared with pure helium. The obtained plasma density is highest for whole time of Uragan-2M operation. The developed scenario allowed to decrease the neutral gas pressure at which the plasma production is possible. This is a requirement for achieving regimes of plasma production with full ionization. Although the initial gas mixture 14%H₂ + 86%He can be treated as optimum, there is no sensitive dependence on hydrogen minority concentration, which makes the scenario robust. This study, together with initial LHD experiments, confirm the prospects of target plasma production by ICRF waves for stellarator type machines.</p></div>","PeriodicalId":634,"journal":{"name":"Journal of Fusion Energy","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10894-022-00326-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5007974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Neutron Flux in EU DEMO Divertor Cassette Body Using HCPB and WCLL Breeding Blanket Models","authors":"Simona Breidokaite,&nbsp;Gediminas Stankunas","doi":"10.1007/s10894-022-00327-7","DOIUrl":"10.1007/s10894-022-00327-7","url":null,"abstract":"<div><p>The paper presents results from neutron flux calculations in the divertor cassette body in cases of Helium Cooled Pebble Bed, and Water-Cooled Lithium Lead concepts are used as a breeding blanket. The same divertor model configuration and specified DEMO neutron source were used for both cases studied. MCNP6 code was used for neutron transport calculations and employing the FENDL-3.1 nuclear data library. |In addition, this paper presents the neutron-induced dose rate calculations performed with support by ADVANTG (AutomateD VAriaNce reducTion Generator) tool and MCNP code, which were used for the variance reduction and particle transport accordingly. The application of such a coupled computational method led to the dose rate and neutron flux maps production, which was obtained for the divertor of the DEMO reactor.</p></div>","PeriodicalId":634,"journal":{"name":"Journal of Fusion Energy","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10894-022-00327-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5213445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correction to: Flow Boiling Burnout in a Hypervapotron Channel Under High Heat Flux and High Sub-Cooling Conditions","authors":"Ji Hwan Lim,&nbsp;Minkyu Park","doi":"10.1007/s10894-022-00325-9","DOIUrl":"10.1007/s10894-022-00325-9","url":null,"abstract":"","PeriodicalId":634,"journal":{"name":"Journal of Fusion Energy","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"52647478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimising Foil Selection for Neutron Activation Systems","authors":"O. Wong,&nbsp;R. Smith,&nbsp;C. R. Nobs,&nbsp;A. M. Bruce","doi":"10.1007/s10894-022-00324-w","DOIUrl":"10.1007/s10894-022-00324-w","url":null,"abstract":"<div><p>Neutron spectrum unfolding using activation foils is currently the primary technique planned for measuring the neutron energy spectrum at the first wall of power-generating fusion reactors. Room for improvement in the effectiveness of current foil selection was identified, and a program produced to select foils procedurally in order to maximise the accuracy of the unfolding procedure. Using Kullback–Leibler Divergence to quantify the accuracy, the spectrum unfolded by the procedurally selected set of foils is found to be more accurate than the spectrum unfolded by a set of foils used in the literature.</p></div>","PeriodicalId":634,"journal":{"name":"Journal of Fusion Energy","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10894-022-00324-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134796381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preface of the PHDIA FUSION 2021 Special Issue: Neutron diagnostics development for ITER, DEMO and IFMIF-DONES","authors":"Didier Mazon","doi":"10.1007/s10894-022-00321-z","DOIUrl":"10.1007/s10894-022-00321-z","url":null,"abstract":"","PeriodicalId":634,"journal":{"name":"Journal of Fusion Energy","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134795713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MHD Analysis on the Physics Design of CFETR Baseline Scenarios","authors":"Ping Zhu,&nbsp;Li Li,&nbsp;Yu Fang,&nbsp;Yuling He,&nbsp;Shuo Wang,&nbsp;Rui Han,&nbsp;Yue Liu,&nbsp;Xiaojing Wang,&nbsp;Yang Zhang,&nbsp;Xiaodong Zhang,&nbsp;Qingquan Yu,&nbsp;Liqun Hu,&nbsp;Huihui Wang,&nbsp;Youwen Sun,&nbsp;Lai Wei,&nbsp;Weikang Tang,&nbsp;Tong Liu,&nbsp;Zhengxiong Wang,&nbsp;Xingting Yan,&nbsp;Wenlong Huang,&nbsp;Yawei Hou,&nbsp;Xiaoquan Ji,&nbsp;Shiyong Zeng,&nbsp;Zafar Abdullah,&nbsp;Zhongyong Chen,&nbsp;Long Zeng,&nbsp;Haolong Li,&nbsp;Zhipeng Chen,&nbsp;Zhijiang Wang,&nbsp;Bo Rao,&nbsp;Ming Zhang,&nbsp;Yonghua Ding,&nbsp;Yuan Pan,&nbsp;the CFETR Physics Team","doi":"10.1007/s10894-022-00323-x","DOIUrl":"10.1007/s10894-022-00323-x","url":null,"abstract":"<div><p>The China Fusion Engineering Test Reactor (CFETR), currently under intensive physics and engineering designs in China, is a major project representative of the low-density steady-state pathway to the controlled fusion energy. One of the primary tasks of the physics design for CFETR is the assessment and analysis of the magnetohydrodynamic (MHD) stability of the proposed design schemes. Comprehensive MHD stability assessment of the CFETR baseline scenarios have led to preliminary progress that may further benefit engineering designs. For CFETR, the electron cyclotron current drive (ECCD) power and current required for the full stabilization of neoclassical tearing mode (NTM) have been predicted in this work, as well as the corresponding controlled magnetic island width. A thorough investigation on resistive wall mode (RWM) stability for CFETR is performed. For 80% of the steady state operation scenarios, active control methods may be required for RWM stabilization. The process of disruption mitigation with massive neon injection on CFETR is simulated. The time scale of and consequences of plasma disruption on CFETR are estimated, which are found equivalent to International Thermonuclear Experimental Reactor (ITER). Major MHD instabilities such as NTM and RWM remain challenge to steady state tokamak operation. On this basis, next steps on CFETR MHD study are planned on NTM, RWM, and shattered pellet injection (SPI) disruption mitigation.</p></div>","PeriodicalId":634,"journal":{"name":"Journal of Fusion Energy","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134795483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}