The main purpose of the divertor tokamak test (DTT) facility is to study alternative solutions to mitigate the issue of the power exhaust, under integrated physics and technical conditions relevant to ITER and DEMO. One of the most complex and innovative subsystems of the entire project is certainly the negative-ion-based neutral beam injector (NBI), meant to inject 10 MW of auxiliary power with a beam of 510 keV deuterium neutrals. This contribution describes the conceptual design of the beamline for the DTT NBI system, with a particular focus on the innovative technical solutions adopted to fulfill the requirements and maximize the performance. The DTT NBI is required to operate with high efficiency in several operating scenarios, covering a large range of beam energies, between 10% and 100% of the nominal value (510 keV). To reach this challenging goal, an innovative accelerator design, the spherical and lemon hyperlens grids (SLHGs), has been developed. The implementation of this design concept of the accelerator has recently become possible thanks to recent improvements in additive manufacturing (AM) technology. Another original aspect of the DTT NBI, compared to existing devices, regards the vacuum pumping system, which will be based on nonevaporable getter (NEG) pumps. This will represent the first application of the NEG technology to an NBI for the heating and current drive system of a fusion experiment, with a possible simplification of the overall construction, with respect to typical solutions based on cryogenic pumps. Other innovative solutions are the cylindrical sawtooth structure (CSS) for the neutralizer panels and the stray field shielding system (SFSS) with encapsulated neutralizer. This article provides an overview of the injector for DTT NBI with a particular focus on innovative technical solutions.
{"title":"Innovative Concepts in the DTT Neutral Beam Injector","authors":"P. Agostinetti;E. Benedetti;R. Bonifetto;M. Bonesso;G. Calabrò;M. Cavenago;F. Crisanti;S. Dal Bello;M. Dalla Palma;D. D’Ambrosio;R. Dima;G. Favero;A. Ferro;M. Fincato;L. Grando;G. Granucci;R. Lombroni;R. Marsilio;A. Murari;T. Patton;A. Pepato;F. Raffaelli;P. Rebesan;M. Recchia;M. Ripani;A. Romano;E. Sartori;M. Scarpari;V. Variale;G. Ventura;F. Veronese;R. Zanino;A. Zappatore;G. Zavarise","doi":"10.1109/TPS.2024.3418133","DOIUrl":"https://doi.org/10.1109/TPS.2024.3418133","url":null,"abstract":"The main purpose of the divertor tokamak test (DTT) facility is to study alternative solutions to mitigate the issue of the power exhaust, under integrated physics and technical conditions relevant to ITER and DEMO. One of the most complex and innovative subsystems of the entire project is certainly the negative-ion-based neutral beam injector (NBI), meant to inject 10 MW of auxiliary power with a beam of 510 keV deuterium neutrals. This contribution describes the conceptual design of the beamline for the DTT NBI system, with a particular focus on the innovative technical solutions adopted to fulfill the requirements and maximize the performance. The DTT NBI is required to operate with high efficiency in several operating scenarios, covering a large range of beam energies, between 10% and 100% of the nominal value (510 keV). To reach this challenging goal, an innovative accelerator design, the spherical and lemon hyperlens grids (SLHGs), has been developed. The implementation of this design concept of the accelerator has recently become possible thanks to recent improvements in additive manufacturing (AM) technology. Another original aspect of the DTT NBI, compared to existing devices, regards the vacuum pumping system, which will be based on nonevaporable getter (NEG) pumps. This will represent the first application of the NEG technology to an NBI for the heating and current drive system of a fusion experiment, with a possible simplification of the overall construction, with respect to typical solutions based on cryogenic pumps. Other innovative solutions are the cylindrical sawtooth structure (CSS) for the neutralizer panels and the stray field shielding system (SFSS) with encapsulated neutralizer. This article provides an overview of the injector for DTT NBI with a particular focus on innovative technical solutions.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 9","pages":"3802-3808"},"PeriodicalIF":1.3,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2024-11-15DOI: 10.1109/TPS.2024.3487896
Ohyung Kwon;Hee-Woon Cheong
We studied a multilayer perceptron model to predict the etch rates of SiO2 and Si3N4 thin films in CF4 plasma using data obtained from a voltage–current (VI) sensor and an optical emission spectrometer (OES). The monitoring data from two devices and etch rate data were collected while varying process parameters such as source power, bias power, and pressure. The data gathered by separately etching a SiO2 coupon or a Si3N4 coupon were determined as training data, and the data gathered by etching both a SiO2 coupon and a Si3N4 coupon simultaneously were determined as test data. We utilized 27 process conditions to obtain training and test data and also employed data augmentation for the training data to improve the learning capability of the model. The multilayer perceptron model trained with data obtained from both the VI sensor and OES showed higher performance in predicting the etch rate of target material in multiple materials than other regression models trained with only data acquired from the OES. This improvement is attributed to the fact that data obtained from the VI sensor includes the information related to ion flux that is proportional to the etch rate and it is not easily captured by only the OES. These results indicate the potential of combining data obtained from the VI sensor and OES to predict the etch rate of target material in multiple materials.
{"title":"Improvement of Multilayer Perceptron Model for Predicting Etch Rates in CF₄ Plasma With Optical Emission Spectrometer and VI Sensor Data","authors":"Ohyung Kwon;Hee-Woon Cheong","doi":"10.1109/TPS.2024.3487896","DOIUrl":"https://doi.org/10.1109/TPS.2024.3487896","url":null,"abstract":"We studied a multilayer perceptron model to predict the etch rates of SiO2 and Si3N4 thin films in CF4 plasma using data obtained from a voltage–current (VI) sensor and an optical emission spectrometer (OES). The monitoring data from two devices and etch rate data were collected while varying process parameters such as source power, bias power, and pressure. The data gathered by separately etching a SiO2 coupon or a Si3N4 coupon were determined as training data, and the data gathered by etching both a SiO2 coupon and a Si3N4 coupon simultaneously were determined as test data. We utilized 27 process conditions to obtain training and test data and also employed data augmentation for the training data to improve the learning capability of the model. The multilayer perceptron model trained with data obtained from both the VI sensor and OES showed higher performance in predicting the etch rate of target material in multiple materials than other regression models trained with only data acquired from the OES. This improvement is attributed to the fact that data obtained from the VI sensor includes the information related to ion flux that is proportional to the etch rate and it is not easily captured by only the OES. These results indicate the potential of combining data obtained from the VI sensor and OES to predict the etch rate of target material in multiple materials.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 10","pages":"5216-5221"},"PeriodicalIF":1.3,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142890241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
The SCILAB-Xcos model for off-axis planar undulator radiation (UR) has been designed. The model calculates the intensity of off-axis radiation based on a numerical approach. The intensity computation results obtained from the SCILAB-Xcos simulation model are compared with analytical results at different harmonics. The results for on-axis radiation were also compared with free software SPECTRA, a synchrotron radiation (SR) calculation code.
{"title":"Simulation of Off-Axis Planar Undulator Radiation by Numerical Approach Using SCILAB-Xcos Model","authors":"Mahazbeen Sayed;Hussain Jeevakhan;Kamal Kumar Kushwaha","doi":"10.1109/TPS.2024.3488900","DOIUrl":"https://doi.org/10.1109/TPS.2024.3488900","url":null,"abstract":"The SCILAB-Xcos model for off-axis planar undulator radiation (UR) has been designed. The model calculates the intensity of off-axis radiation based on a numerical approach. The intensity computation results obtained from the SCILAB-Xcos simulation model are compared with analytical results at different harmonics. The results for on-axis radiation were also compared with free software SPECTRA, a synchrotron radiation (SR) calculation code.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 10","pages":"5296-5302"},"PeriodicalIF":1.3,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142890237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Vacuum arc widely appears in vacuum interrupters, ion sources, thrusters, and other related application fields. Understanding the components’ characteristics in vacuum arc is very important for the above application fields. At present, modeling and numerical simulation technology is becoming more and more important for the study of vacuum arc mechanisms. In this article, multicomponent magnetohydrodynamic (MHD) models of vacuum arc with passive and active anode modes will be reviewed, and the commercial alloy electrode materials in vacuum interrupters will be considered. The influence of the spatial magnetic field generated by commercial electrodes on the arc was studied. Furthermore, transient plasma characteristics and component evolution processes of vacuum arcs with different situations (fixed gap distance and electrode movement) in vacuum interrupters are reviewed. Vacuum arc plasma jet characteristics with a ring anode under different external magnetic fields will also be introduced, and the separation mechanisms of light and heavy ions in vacuum arcs will also be studied. Finally, the challenge of vacuum arc modeling in the future is also discussed.
{"title":"Research Progress of Modeling and Simulation of Vacuum Arcs Considering Multicomponents With Different Anode Modes","authors":"Lijun Wang;Jieli Chen;Zhefeng Zhang;Runming Zhang;Cong Wang;Shenli Jia","doi":"10.1109/TPS.2024.3485966","DOIUrl":"https://doi.org/10.1109/TPS.2024.3485966","url":null,"abstract":"Vacuum arc widely appears in vacuum interrupters, ion sources, thrusters, and other related application fields. Understanding the components’ characteristics in vacuum arc is very important for the above application fields. At present, modeling and numerical simulation technology is becoming more and more important for the study of vacuum arc mechanisms. In this article, multicomponent magnetohydrodynamic (MHD) models of vacuum arc with passive and active anode modes will be reviewed, and the commercial alloy electrode materials in vacuum interrupters will be considered. The influence of the spatial magnetic field generated by commercial electrodes on the arc was studied. Furthermore, transient plasma characteristics and component evolution processes of vacuum arcs with different situations (fixed gap distance and electrode movement) in vacuum interrupters are reviewed. Vacuum arc plasma jet characteristics with a ring anode under different external magnetic fields will also be introduced, and the separation mechanisms of light and heavy ions in vacuum arcs will also be studied. Finally, the challenge of vacuum arc modeling in the future is also discussed.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 9","pages":"4402-4418"},"PeriodicalIF":1.3,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142798018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2024-11-14DOI: 10.1109/TPS.2024.3474713
Pramila Gautam;Vismaysinh Raulji;Rohit Kumar;Rachana Rajpal;Rakesh Tanna;Joydeep Ghosh;Aditya-U Team
Real-time techniques are crucial in tokamaks to stabilize plasma position and achieve longer discharges. ADITYA-U uses real-time feedback control of the equilibrium field to stabilize the horizontal plasma position and improve plasma parameters. This innovative control system, developed using the NI-PXI-7831R card in a PXI chassis, featured an integrated PID controller. The PID controller generates control signals for the fast-feedback coils, resulting in successful control of the horizontal plasma position. However, the initial control system had some limitations. Therefore, it was upgraded using the Compact-RIO (c-RIO), for better control and flexibility in adjusting PID parameters. This upgrade allowed for longer durations of discharge of ~400 ms and improved data retrieval capabilities. The full paper will provide more details on the upgraded system and its performance in the ADITYA-U tokamak.
{"title":"Improved Horizontal Plasma Position Control Using c-RIO-Based Real Time System in Aditya-U","authors":"Pramila Gautam;Vismaysinh Raulji;Rohit Kumar;Rachana Rajpal;Rakesh Tanna;Joydeep Ghosh;Aditya-U Team","doi":"10.1109/TPS.2024.3474713","DOIUrl":"https://doi.org/10.1109/TPS.2024.3474713","url":null,"abstract":"Real-time techniques are crucial in tokamaks to stabilize plasma position and achieve longer discharges. ADITYA-U uses real-time feedback control of the equilibrium field to stabilize the horizontal plasma position and improve plasma parameters. This innovative control system, developed using the NI-PXI-7831R card in a PXI chassis, featured an integrated PID controller. The PID controller generates control signals for the fast-feedback coils, resulting in successful control of the horizontal plasma position. However, the initial control system had some limitations. Therefore, it was upgraded using the Compact-RIO (c-RIO), for better control and flexibility in adjusting PID parameters. This upgrade allowed for longer durations of discharge of ~400 ms and improved data retrieval capabilities. The full paper will provide more details on the upgraded system and its performance in the ADITYA-U tokamak.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 9","pages":"3809-3813"},"PeriodicalIF":1.3,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2024-11-13DOI: 10.1109/TPS.2024.3492042
Han Xu;Zipeng Wei;Lei Quan;Yihong Huang;Hao Zhang;Mingxu Shao;Kai Xie
The use of plasma-activated water (PAW) is receiving increasing attention as a sustainable technique for efficient biological and chemical decontamination. In the novel approach used in this study, a combination of a plasma-jet-activated gas bubble sparger and a liquid stirrer was used to maximize or effectively scale the efficiency of treatment with PAW. The plasma discharge and gas-liquid mass transfer can be enhanced synchronously. The dynamic behavior of the liquid vortex and bubble splitting significantly increase the gas-liquid mixing performance, and this enhances the mass transfer of plasma reactive species. Spatiotemporal propagation of the plasma jet is enhanced to a certain extent because of the negative pressure formed by stirrer rotation. This synergistic effect effectively increases the concentration of aqueous reactive oxygen and nitrogen species, and the oxidative capacity of PAW. This results in enhanced kinetic rate constants and a high energy yield in methyl orange (MO) degradation. The use of stirrer rotation to increase the reactive capacity of a plasma-bubble two-phase flow reactor could facilitate the development of alternative methods for degrading recalcitrant chemicals without the need for chemical dosage.
{"title":"Enhancement of Plasma Jets and Plasma-Activated Water by Using Liquid Agitated Air-Bubble Diffuser","authors":"Han Xu;Zipeng Wei;Lei Quan;Yihong Huang;Hao Zhang;Mingxu Shao;Kai Xie","doi":"10.1109/TPS.2024.3492042","DOIUrl":"https://doi.org/10.1109/TPS.2024.3492042","url":null,"abstract":"The use of plasma-activated water (PAW) is receiving increasing attention as a sustainable technique for efficient biological and chemical decontamination. In the novel approach used in this study, a combination of a plasma-jet-activated gas bubble sparger and a liquid stirrer was used to maximize or effectively scale the efficiency of treatment with PAW. The plasma discharge and gas-liquid mass transfer can be enhanced synchronously. The dynamic behavior of the liquid vortex and bubble splitting significantly increase the gas-liquid mixing performance, and this enhances the mass transfer of plasma reactive species. Spatiotemporal propagation of the plasma jet is enhanced to a certain extent because of the negative pressure formed by stirrer rotation. This synergistic effect effectively increases the concentration of aqueous reactive oxygen and nitrogen species, and the oxidative capacity of PAW. This results in enhanced kinetic rate constants and a high energy yield in methyl orange (MO) degradation. The use of stirrer rotation to increase the reactive capacity of a plasma-bubble two-phase flow reactor could facilitate the development of alternative methods for degrading recalcitrant chemicals without the need for chemical dosage.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 10","pages":"5193-5204"},"PeriodicalIF":1.3,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142890228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2024-11-13DOI: 10.1109/TPS.2024.3403722
Hao Lin;Pan Liu;Wenzai An;Xin Yan;Shen Wu;Ningli Wang
The objective was to investigate immediate ocular damage in exposed to 34.5-terahertz (THz) electromagnetic wave generated by quantum cascade laser (QCL). This research developed the damage porcine model for THz exposure, and its damage occurrence threshold values of time dimension and energy dimension were obtained. The right eyes were exposed to 34.5-THz spot from fiber, and the contralateral eyes were used as control eyes. Slit-lamp examination 5 min after THz exposure revealed a semicircular area of opacity characterized by fluorescein staining, indicating damaged corneal epithelial cells in the irradiated area and encircling by corneal edema. Hematoxylin-eosin (HE) staining suggested the irradiated corneas over 2 min exposure contained fewer epithelial cell layers with vacuolated cells, swollen endothelium, and edematous stroma, compared to contralateral corneas. In vivo evidence suggested exposure time over 6 min or energy over 40 mW leaded to full-thickness detachment of the corneal epithelium. The damage was present when the energy of THz wave was greater than 20 mW or the exposure time was longer than 2 min.
{"title":"Porcine Corneal Injuries and Investigation of Damage Thresholds of High-Frequency Terahertz Wave","authors":"Hao Lin;Pan Liu;Wenzai An;Xin Yan;Shen Wu;Ningli Wang","doi":"10.1109/TPS.2024.3403722","DOIUrl":"https://doi.org/10.1109/TPS.2024.3403722","url":null,"abstract":"The objective was to investigate immediate ocular damage in exposed to 34.5-terahertz (THz) electromagnetic wave generated by quantum cascade laser (QCL). This research developed the damage porcine model for THz exposure, and its damage occurrence threshold values of time dimension and energy dimension were obtained. The right eyes were exposed to 34.5-THz spot from fiber, and the contralateral eyes were used as control eyes. Slit-lamp examination 5 min after THz exposure revealed a semicircular area of opacity characterized by fluorescein staining, indicating damaged corneal epithelial cells in the irradiated area and encircling by corneal edema. Hematoxylin-eosin (HE) staining suggested the irradiated corneas over 2 min exposure contained fewer epithelial cell layers with vacuolated cells, swollen endothelium, and edematous stroma, compared to contralateral corneas. In vivo evidence suggested exposure time over 6 min or energy over 40 mW leaded to full-thickness detachment of the corneal epithelium. The damage was present when the energy of THz wave was greater than 20 mW or the exposure time was longer than 2 min.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 9","pages":"4735-4738"},"PeriodicalIF":1.3,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2024-11-13DOI: 10.1109/TPS.2024.3492000
Elamine Benkhelifa;Mourad Djebli
We investigated hybrid modes and traveling wave propagation in an ultracold atomic gas. Using both fluid and kinetic plasma description models, we treat the nonlinear oscillation modes of a cloud of ultracold atoms confined in a magneto-optical trap (MOT). The effect of repulsive forces between nearby atoms is discussed, through the key parameter $z_{mathrm { eff }}q_{mathrm { eff}}$ which ranges from $10^{-5}e$ to $10^{-3}e$ . The gas is treated as an effective plasma-like single species. We focused on wave propagation dynamics, considering only thermal pressure and effective Coulomb interaction effects. A small amplitude wave analysis revealed the existence of nonlinear plasma-like oscillations and cnoidal structure waves governed by the effective charge number ( $z_{mathrm { eff}}$ ).
{"title":"On the 1-D Plasma-Like Model for Studying Nonlinear Oscillations and Wave Propagation in Ultracold Gases","authors":"Elamine Benkhelifa;Mourad Djebli","doi":"10.1109/TPS.2024.3492000","DOIUrl":"https://doi.org/10.1109/TPS.2024.3492000","url":null,"abstract":"We investigated hybrid modes and traveling wave propagation in an ultracold atomic gas. Using both fluid and kinetic plasma description models, we treat the nonlinear oscillation modes of a cloud of ultracold atoms confined in a magneto-optical trap (MOT). The effect of repulsive forces between nearby atoms is discussed, through the key parameter \u0000<inline-formula> <tex-math>$z_{mathrm { eff }}q_{mathrm { eff}}$ </tex-math></inline-formula>\u0000 which ranges from \u0000<inline-formula> <tex-math>$10^{-5}e$ </tex-math></inline-formula>\u0000 to \u0000<inline-formula> <tex-math>$10^{-3}e$ </tex-math></inline-formula>\u0000. The gas is treated as an effective plasma-like single species. We focused on wave propagation dynamics, considering only thermal pressure and effective Coulomb interaction effects. A small amplitude wave analysis revealed the existence of nonlinear plasma-like oscillations and cnoidal structure waves governed by the effective charge number (\u0000<inline-formula> <tex-math>$z_{mathrm { eff}}$ </tex-math></inline-formula>\u0000).","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 10","pages":"5138-5144"},"PeriodicalIF":1.3,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142890140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
The Experimental Advanced Superconducting Tokamak (EAST) electron cyclotron resonance heating (ECRH) is an important auxiliary heating method, helping EAST achieve 1056 s of super I-mode discharge. There are currently four subsystems with six gyrotrons on EAST. At present, the EAST ECRH system can stably output 3.2-MW radio frequency (RF) power at 140 GHz with long pulses above 100 s (up to 1000 s) and can output 1.3-MW RF power at 105 GHz with long pulses above 100 s. Using ECRH as one of the main heating methods, EAST has made a series of experimental progress in recent years. In April 2023, the steady-state H mode plasma of 403 s was obtained. In the next two years, we plan to develop #5 and #6 systems. After the development, the total RF power can reach 5 MW at 140 GHz. In this article, the composition and operation of the EAST ECRH system were introduced, and the development advances of gyrotrons, transmission lines (TLs), and antennas were discussed. We analyzed the key characteristics related to the long-term operation instability of gyrotrons, which is an important reference for the operation of future gyrotrons.
{"title":"Advances and Prospects of ECRH System on EAST","authors":"Weiye Xu;Handong Xu;Dajun Wu;Yong Yang;Jian Zhang;Xiaojie Wang;Jian Wang;Yongzhong Hou;Liyuan Zhang;Miaohui Li","doi":"10.1109/TPS.2024.3493092","DOIUrl":"https://doi.org/10.1109/TPS.2024.3493092","url":null,"abstract":"The Experimental Advanced Superconducting Tokamak (EAST) electron cyclotron resonance heating (ECRH) is an important auxiliary heating method, helping EAST achieve 1056 s of super I-mode discharge. There are currently four subsystems with six gyrotrons on EAST. At present, the EAST ECRH system can stably output 3.2-MW radio frequency (RF) power at 140 GHz with long pulses above 100 s (up to 1000 s) and can output 1.3-MW RF power at 105 GHz with long pulses above 100 s. Using ECRH as one of the main heating methods, EAST has made a series of experimental progress in recent years. In April 2023, the steady-state H mode plasma of 403 s was obtained. In the next two years, we plan to develop #5 and #6 systems. After the development, the total RF power can reach 5 MW at 140 GHz. In this article, the composition and operation of the EAST ECRH system were introduced, and the development advances of gyrotrons, transmission lines (TLs), and antennas were discussed. We analyzed the key characteristics related to the long-term operation instability of gyrotrons, which is an important reference for the operation of future gyrotrons.","PeriodicalId":450,"journal":{"name":"IEEE Transactions on Plasma Science","volume":"52 10","pages":"5159-5172"},"PeriodicalIF":1.3,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142890244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pub Date : 2024-11-13DOI: 10.1109/TPS.2024.3487079
Connor Gunter;Scott D. Kovaleski;Junyoung Shin;Elizabeth Bellott;Matthew Maschmann;Brandon Weatherford
This work characterizes the bulk emission properties of carbon nanotube (CNT) forest cathodes fabricated with various geometries. Geometries explored include dense nanotube forests of varying height grown on $5times 5$ mm silicon (Si) substrates and discrete, patterned CNT pillars fabricated using UV photolithography. Dense forests heights ranged from $526~mu text { m}$ to 1.41 mm, with packing fraction for dense forest calculated to be 4e10 nanotubes/cm2 based on an average nanotube separation distance of 100 nm for fixed growth dense forests. Patterned sample micro pillar heights ranged from 47 to $393~mu text { m}$ with pillar widths on tested samples ranging from 250 to $270~mu text { m}$ . Properties explored include emission current, turn-on field, and emission current performance over time. A parallel plate electron beam diode with a 100- $mu text { m}$ A-K gap and an automated test apparatus were developed to provide a configurable experiment that provides accurate and repeatable measurements for dc, dc sweep, and timed performance testing. Operating voltages for the voltage sweeps spanned from 0 to −350 V. Testing has shown evidence of a hysteresis effect on the emission current tied to the applied field history as well as shifting of the turn-on field magnitude throughout the testing period, suggesting a conditioning effect during use. Three separate emission regions in the I–V curves during sweep testing have also been observed. In the geometric study, dense forests and patterned samples were sweep tested up to a peak applied voltage of −250 V, with the taller samples generally performing better. Currents produced in the geometric study from the dense forest emitters ranged from 36.8 to $572.34~mu text { A}$ , with current densities ranging from 15 to 2.29 mA/cm2. Currents produced from the patterned micropillar emitters ranged from 39.4 to $317.51~mu text { A}$ , with current densities ranging from 67 to 3 mA/cm2. DC time testing showed a relatively stable output current over a 4.5-h testing period. The findings of this work aim to explore CNT emitters as a viable alternative to thermionic cathodes used in large RF systems and to characterize connection between CNT emitter geometry and the resulting emission performance. The insights gained from this work will be used for informed design and optimization of future emitters.
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