Pub Date : 2024-05-08DOI: 10.1088/1361-6587/ad4419
S Munaretto, Y Q Liu, D A Ryan, G Z Hao, J W Berkery, S Blackmore, L Kogan
Achieving edge localized modes (ELMs) suppression in spherical tokamaks by applying resonant magnetic perturbations (RMPs) has proven challenging. The poloidal spectrum of the applied RMP is a key parameter that has an impact on the capability to mitigate and eventually suppress ELMs. In this work the resistive magnetohydrodynamic code MARS-F (Liu et al 2000 Phys. Plasmas7 3681) is used to evaluate the possibility of directly measuring the plasma response in MAST-U, and particularly its variation as function of the applied poloidal spectrum, in order to guide the experimental validation of the predicted best RMP configuration for ELM suppression. Toroidal mode number n = 2 RMP is considered to minimize the presence of sidebands, and to avoid the deleterious core coupling of n = 1. Singular Value Decomposition is used to highlight linearly independent structures in the simulated magnetic 3D fields and how those structures can be measured at the wall where the magnetic sensors are located. Alternative ways to measure the multimodal plasma response and how they can be used to infer the best RMP configuration to achieve ELM suppression are also presented, including the plasma displacement and the 3D footprints at the divertor plates.
事实证明，在球形托卡马克中通过应用共振磁扰动（RMPs）来实现边缘局部模态（ELMs）抑制具有挑战性。所应用的 RMP 的极谱是一个关键参数，会影响减轻并最终抑制 ELM 的能力。在这项工作中，电阻磁流体动力学代码 MARS-F（Liu 等人，2000 年，Phys. Plasmas7 3681）被用来评估直接测量 MAST-U 中等离子体响应的可能性，特别是其作为外加极谱函数的变化，以指导对预测的抑制 ELM 的最佳 RMP 配置的实验验证。环形模式数 n = 2 RMP 被认为可以最大限度地减少边带的存在，并避免 n = 1 的有害核心耦合。奇异值分解用于突出模拟三维磁场中的线性独立结构，以及如何在磁传感器所在的壁面测量这些结构。此外，还介绍了测量多模态等离子体响应的其他方法，以及如何利用这些方法来推断实现 ELM 抑制的最佳 RMP 配置，包括等离子体位移和分流板的三维足迹。
{"title":"Chasing the multi-modal plasma response in MAST-U","authors":"S Munaretto, Y Q Liu, D A Ryan, G Z Hao, J W Berkery, S Blackmore, L Kogan","doi":"10.1088/1361-6587/ad4419","DOIUrl":"https://doi.org/10.1088/1361-6587/ad4419","url":null,"abstract":"Achieving edge localized modes (ELMs) suppression in spherical tokamaks by applying resonant magnetic perturbations (RMPs) has proven challenging. The poloidal spectrum of the applied RMP is a key parameter that has an impact on the capability to mitigate and eventually suppress ELMs. In this work the resistive magnetohydrodynamic code MARS-F (Liu <italic toggle=\"yes\">et al</italic> 2000 <italic toggle=\"yes\">Phys. Plasmas</italic>\u0000<bold>7</bold> 3681) is used to evaluate the possibility of directly measuring the plasma response in MAST-U, and particularly its variation as function of the applied poloidal spectrum, in order to guide the experimental validation of the predicted best RMP configuration for ELM suppression. Toroidal mode number <italic toggle=\"yes\">n</italic> = 2 RMP is considered to minimize the presence of sidebands, and to avoid the deleterious core coupling of <italic toggle=\"yes\">n</italic> = 1. Singular Value Decomposition is used to highlight linearly independent structures in the simulated magnetic 3D fields and how those structures can be measured at the wall where the magnetic sensors are located. Alternative ways to measure the multimodal plasma response and how they can be used to infer the best RMP configuration to achieve ELM suppression are also presented, including the plasma displacement and the 3D footprints at the divertor plates.","PeriodicalId":20239,"journal":{"name":"Plasma Physics and Controlled Fusion","volume":"5 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140932137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-05-06DOI: 10.1088/1361-6587/ad441a
A P L Robinson
It is argued that fusion chain reactions in the D-D system is feasible with supra-thermal deuterons in the MeV regime, with new generations of deuterons being generated either via neutron–deuteron or proton–deuteron collisions. The propagation of supra-thermal deuterons in an infinite, hot, dense deuterium target was studied using a Monte Carlo method that includes multiple nuclear reactions, electron and ion stopping, along with neutron and proton knock-ons. Over a wide range of densities we observed significant, albeit sub-critical chain reactions in the multi-keV temperature regime. At very high densities (over 1000 gcm−3) and temperatures (over 40 keV) we observed chain reactions that reached criticality. These results suggest that there is a case to re-assess the potential of inertial confinement fusion based on deuterium-heavy targets.
{"title":"Suprathermal-ion-driven fusion chain reactions in the pure deuterium system","authors":"A P L Robinson","doi":"10.1088/1361-6587/ad441a","DOIUrl":"https://doi.org/10.1088/1361-6587/ad441a","url":null,"abstract":"It is argued that fusion chain reactions in the D-D system is feasible with supra-thermal deuterons in the MeV regime, with new generations of deuterons being generated either via neutron–deuteron or proton–deuteron collisions. The propagation of supra-thermal deuterons in an infinite, hot, dense deuterium target was studied using a Monte Carlo method that includes multiple nuclear reactions, electron and ion stopping, along with neutron and proton knock-ons. Over a wide range of densities we observed significant, albeit sub-critical chain reactions in the multi-keV temperature regime. At very high densities (over 1000 gcm−3) and temperatures (over 40 keV) we observed chain reactions that reached criticality. These results suggest that there is a case to re-assess the potential of inertial confinement fusion based on deuterium-heavy targets.","PeriodicalId":20239,"journal":{"name":"Plasma Physics and Controlled Fusion","volume":"35 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140889913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-05-06DOI: 10.1088/1361-6587/ad4417
Qinglai Qiu, Yang Zhang, Xiaodong Zhang, Qiping Yuan, Zhengping Luo, Zhaoliang Wang, Yibing Wu, Jing Qian, Bin Guo, Ruirong Liang, Yuehang Wang, Jianjun Chen, Yao Huang, Bingjia Xiao, Lingyi Meng and the East Team
In 2021, EAST was equipped with a full-ring divertor coil to facilitate research on the fish tail divertor concept. Initially, it was observed that the coil current had a negligible ability to sweep the strike point. Conversely, when the amplitude and frequency of the alternating current were marginally increased, there was a significant interruption to plasma control. This perturbation was attributed to the poloidal control field’s limited response rate to the coil’s fluctuations. To address this issue, novel control methodologies were devised to ensure stable and effective sweeping of the strike point using the divertor coil. The devised methods are twofold: For high-frequency strike point control, a low-pass filter decoupling technique based on ISOFLUX control strategy enabled achieving a sweeping frequency of 100 Hz. This strategy allowed for consistent plasma management without compromising average stored energy or density regulation. Resulting from this proficient manipulation of the strike point, a reduction in the peak temperature of the divertor plate was observed. For low-frequency sweeping, a static multi-input multi-output decoupling approach was developed, facilitating concurrent sweeping of both the outer and inner strike points.
{"title":"Optimizing control for strike point sweeping using lower divertor coil in EAST","authors":"Qinglai Qiu, Yang Zhang, Xiaodong Zhang, Qiping Yuan, Zhengping Luo, Zhaoliang Wang, Yibing Wu, Jing Qian, Bin Guo, Ruirong Liang, Yuehang Wang, Jianjun Chen, Yao Huang, Bingjia Xiao, Lingyi Meng and the East Team","doi":"10.1088/1361-6587/ad4417","DOIUrl":"https://doi.org/10.1088/1361-6587/ad4417","url":null,"abstract":"In 2021, EAST was equipped with a full-ring divertor coil to facilitate research on the fish tail divertor concept. Initially, it was observed that the coil current had a negligible ability to sweep the strike point. Conversely, when the amplitude and frequency of the alternating current were marginally increased, there was a significant interruption to plasma control. This perturbation was attributed to the poloidal control field’s limited response rate to the coil’s fluctuations. To address this issue, novel control methodologies were devised to ensure stable and effective sweeping of the strike point using the divertor coil. The devised methods are twofold: For high-frequency strike point control, a low-pass filter decoupling technique based on ISOFLUX control strategy enabled achieving a sweeping frequency of 100 Hz. This strategy allowed for consistent plasma management without compromising average stored energy or density regulation. Resulting from this proficient manipulation of the strike point, a reduction in the peak temperature of the divertor plate was observed. For low-frequency sweeping, a static multi-input multi-output decoupling approach was developed, facilitating concurrent sweeping of both the outer and inner strike points.","PeriodicalId":20239,"journal":{"name":"Plasma Physics and Controlled Fusion","volume":"161 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140882537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-05-06DOI: 10.1088/1361-6587/ad4175
S Guizzo, A O Nelson, C Hansen, F Logak and C Paz-Soldan
Negative triangularity (NT) tokamak configurations may be more susceptible to magneto-hydrodynamic instability, posing challenges for recent reactor designs centered around their favorable properties, such as improved confinement and operation free of edge-localized modes. In this work, we assess the vertical stability of plasmas with NT shaping and develop potential reactor solutions. When coupled with a conformal wall, NT equilibria are confirmed to be less vertically stable than equivalent positive triangularity (PT) configurations. Unlike PT, their vertical stability is degraded at higher poloidal beta. Furthermore, improvements in vertical stability at low aspect ratio do not translate to the NT geometry. NT equilibria are stabilized in PT vacuum vessels due to the increased proximity of the plasma and the wall on the outboard side, but this scenario is found to be undesirable due to reduced vertical gaps which give less spatial margin for control recovery. Instead, we demonstrate that informed positioning of passively conducting plates can lead to improved vertical stability in NT configurations on par with stability metrics expected in PT scenarios. An optimal setup for passive plates in highly elongated NT devices is presented, where plates on the outboard side of the device reduce vertical instability growth rates to 16% of their baseline value. For lower target elongations, integration of passive stabilizers with divertor concepts can lead to significant improvements in vertical stability. Plates on the inboard side of the device are also uniquely enabled in NT geometries, providing opportunity for spatial separation of vertical stability coils and passive stabilizers.
负三角形（NT）托卡马克构型可能更容易受到磁流体动力不稳定性的影响，这给近期以其有利特性为中心的反应堆设计带来了挑战，例如改进的约束性和无边缘定位模式的运行。在这项工作中，我们评估了等离子体在 NT 塑造下的垂直稳定性，并开发了潜在的反应堆解决方案。经证实，当与共形壁耦合时，NT 平衡的垂直稳定性低于等效的正三角形（PT）配置。与正三角形构型不同的是，其垂直稳定性在较高极性贝塔时会降低。此外，低纵横比时垂直稳定性的提高并没有转化为 NT 几何结构。在 PT 真空容器中，由于等离子体和外侧壁的距离增加，NT 平衡得到了稳定，但由于垂直间隙减小，控制恢复的空间余量减少，这种情况并不理想。相反，我们证明了被动导电板的明智定位可以提高 NT 配置的垂直稳定性，与 PT 方案中预期的稳定性指标相当。我们提出了高伸长 NT 设备中被动板的最佳设置，其中位于设备外侧的板可将垂直不稳定性增长率降至基线值的 16%。对于较低的目标伸长率，将被动稳定器与分流器概念相结合可显著提高垂直稳定性。装置内侧的板在 NT 几何结构中也是独一无二的，为垂直稳定线圈和被动稳定器的空间分离提供了机会。
{"title":"Assessment of vertical stability for negative triangularity pilot plants","authors":"S Guizzo, A O Nelson, C Hansen, F Logak and C Paz-Soldan","doi":"10.1088/1361-6587/ad4175","DOIUrl":"https://doi.org/10.1088/1361-6587/ad4175","url":null,"abstract":"Negative triangularity (NT) tokamak configurations may be more susceptible to magneto-hydrodynamic instability, posing challenges for recent reactor designs centered around their favorable properties, such as improved confinement and operation free of edge-localized modes. In this work, we assess the vertical stability of plasmas with NT shaping and develop potential reactor solutions. When coupled with a conformal wall, NT equilibria are confirmed to be less vertically stable than equivalent positive triangularity (PT) configurations. Unlike PT, their vertical stability is degraded at higher poloidal beta. Furthermore, improvements in vertical stability at low aspect ratio do not translate to the NT geometry. NT equilibria are stabilized in PT vacuum vessels due to the increased proximity of the plasma and the wall on the outboard side, but this scenario is found to be undesirable due to reduced vertical gaps which give less spatial margin for control recovery. Instead, we demonstrate that informed positioning of passively conducting plates can lead to improved vertical stability in NT configurations on par with stability metrics expected in PT scenarios. An optimal setup for passive plates in highly elongated NT devices is presented, where plates on the outboard side of the device reduce vertical instability growth rates to 16% of their baseline value. For lower target elongations, integration of passive stabilizers with divertor concepts can lead to significant improvements in vertical stability. Plates on the inboard side of the device are also uniquely enabled in NT geometries, providing opportunity for spatial separation of vertical stability coils and passive stabilizers.","PeriodicalId":20239,"journal":{"name":"Plasma Physics and Controlled Fusion","volume":"16 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140882733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-05-02DOI: 10.1088/1361-6587/ad4174
D A Kaltsas, A Kuiroukidis, P J Morrison and G N Throumoulopoulos
We derive axisymmetric equilibrium equations in the context of the hybrid Vlasov model with kinetic ions and massless fluid electrons, assuming isothermal electrons and deformed Maxwellian distribution functions for the kinetic ions. The equilibrium system comprises a Grad–Shafranov partial differential equation and an integral equation. These equations can be utilized to calculate the equilibrium magnetic field and ion distribution function, respectively, for given particle density or given ion and electron toroidal current density profiles. The resulting solutions describe states characterized by toroidal plasma rotation and toroidal electric current density. Additionally, due to the presence of fluid electrons, these equilibria also exhibit a poloidal current density component. This is in contrast to the fully kinetic Vlasov model, where axisymmetric Jeans equilibria can only accommodate toroidal currents and flows, given the absence of a third integral of the microscopic motion.
{"title":"Axisymmetric hybrid Vlasov equilibria with applications to tokamak plasmas","authors":"D A Kaltsas, A Kuiroukidis, P J Morrison and G N Throumoulopoulos","doi":"10.1088/1361-6587/ad4174","DOIUrl":"https://doi.org/10.1088/1361-6587/ad4174","url":null,"abstract":"We derive axisymmetric equilibrium equations in the context of the hybrid Vlasov model with kinetic ions and massless fluid electrons, assuming isothermal electrons and deformed Maxwellian distribution functions for the kinetic ions. The equilibrium system comprises a Grad–Shafranov partial differential equation and an integral equation. These equations can be utilized to calculate the equilibrium magnetic field and ion distribution function, respectively, for given particle density or given ion and electron toroidal current density profiles. The resulting solutions describe states characterized by toroidal plasma rotation and toroidal electric current density. Additionally, due to the presence of fluid electrons, these equilibria also exhibit a poloidal current density component. This is in contrast to the fully kinetic Vlasov model, where axisymmetric Jeans equilibria can only accommodate toroidal currents and flows, given the absence of a third integral of the microscopic motion.","PeriodicalId":20239,"journal":{"name":"Plasma Physics and Controlled Fusion","volume":"46 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140839285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-05-01DOI: 10.1088/1361-6587/ad4176
Minjun J Choi, Jae-Min Kwon, Lei Qi, P H Diamond, T S Hahm, Hogun Jhang, Juhyung Kim, M Leconte, Hyun-Seok Kim, Jisung Kang, Byoung-Ho Park, Jinil Chung, Jaehyun Lee, Minho Kim, Gunsu S Yun, Y U Nam, Jaewook Kim, Won-Ha Ko, K D Lee, J W Juhn and the KSTAR Team
The self-organization is one of the most interesting phenomena in the non-equilibrium complex system, generating ordered structures of different sizes and durations. In tokamak plasmas, various self-organized phenomena have been reported, and two of them, coexisting in the near-marginal (interaction dominant) regime, are avalanches and the E × B staircase. Avalanches mean the ballistic flux propagation event through successive interactions as it propagates, and the E × B staircase means a globally ordered pattern of self-organized zonal flow layers. Various models have been suggested to understand their characteristics and relation, but experimental researches have been mostly limited to the demonstration of their existence. Here we report detailed analyses of their dynamics and statistics and explain their relation. Avalanches influence the formation and the width distribution of the E × B staircase, while the E × B staircase confines avalanches within its mesoscopic width until dissipated or penetrated. Our perspective to consider them the self-organization phenomena enhances our fundamental understanding of them as well as links our findings with the self-organization of mesoscopic structures in various complex systems.
自组织是非平衡复杂系统中最有趣的现象之一，可产生不同大小和持续时间的有序结构。据报道，在托卡马克等离子体中存在多种自组织现象，其中两种共存于近边缘（相互作用占主导地位）体系中，它们是雪崩和 E × B 阶梯。雪崩指的是在传播过程中通过连续相互作用的弹流传播事件，而 E × B 阶梯指的是自组织带状流层的全局有序模式。人们提出了各种模型来理解它们的特征和关系，但实验研究大多仅限于证明它们的存在。在此，我们将详细分析它们的动力学和统计量，并解释它们之间的关系。雪崩影响 E × B 阶梯的形成和宽度分布，而 E × B 阶梯则将雪崩限制在其介观宽度内，直至消散或穿透。我们将它们视为自组织现象的观点增强了我们对它们的基本理解，并将我们的发现与各种复杂系统中介观结构的自组织联系起来。
{"title":"Mesoscopic transport in KSTAR plasmas: avalanches and the E × B staircase","authors":"Minjun J Choi, Jae-Min Kwon, Lei Qi, P H Diamond, T S Hahm, Hogun Jhang, Juhyung Kim, M Leconte, Hyun-Seok Kim, Jisung Kang, Byoung-Ho Park, Jinil Chung, Jaehyun Lee, Minho Kim, Gunsu S Yun, Y U Nam, Jaewook Kim, Won-Ha Ko, K D Lee, J W Juhn and the KSTAR Team","doi":"10.1088/1361-6587/ad4176","DOIUrl":"https://doi.org/10.1088/1361-6587/ad4176","url":null,"abstract":"The self-organization is one of the most interesting phenomena in the non-equilibrium complex system, generating ordered structures of different sizes and durations. In tokamak plasmas, various self-organized phenomena have been reported, and two of them, coexisting in the near-marginal (interaction dominant) regime, are avalanches and the E × B staircase. Avalanches mean the ballistic flux propagation event through successive interactions as it propagates, and the E × B staircase means a globally ordered pattern of self-organized zonal flow layers. Various models have been suggested to understand their characteristics and relation, but experimental researches have been mostly limited to the demonstration of their existence. Here we report detailed analyses of their dynamics and statistics and explain their relation. Avalanches influence the formation and the width distribution of the E × B staircase, while the E × B staircase confines avalanches within its mesoscopic width until dissipated or penetrated. Our perspective to consider them the self-organization phenomena enhances our fundamental understanding of them as well as links our findings with the self-organization of mesoscopic structures in various complex systems.","PeriodicalId":20239,"journal":{"name":"Plasma Physics and Controlled Fusion","volume":"11 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140839120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-04-30DOI: 10.1088/1361-6587/ad3fe4
Chao Dong, Ding Li
The collision term of a magnetized plasma is re-derived. It is found that the results of Rostoker (1960 Phys. Fluids3 922) and Hassan and Watson (1977 Plasma Phys.19 237) are correct while the result of Erofeev (2023 Plasma Phys. Control. Fusion65 085014) is not.
{"title":"Comment on ‘The influence of plasma evolution on a kinetic scenario of collisional relaxation of a magnetized plasma’","authors":"Chao Dong, Ding Li","doi":"10.1088/1361-6587/ad3fe4","DOIUrl":"https://doi.org/10.1088/1361-6587/ad3fe4","url":null,"abstract":"The collision term of a magnetized plasma is re-derived. It is found that the results of Rostoker (1960 <italic toggle=\"yes\">Phys. Fluids</italic>\u0000<bold>3</bold> 922) and Hassan and Watson (1977 <italic toggle=\"yes\">Plasma Phys.</italic>\u0000<bold>19</bold> 237) are correct while the result of Erofeev (2023 <italic toggle=\"yes\">Plasma Phys. Control. Fusion</italic>\u0000<bold>65</bold> 085014) is not.","PeriodicalId":20239,"journal":{"name":"Plasma Physics and Controlled Fusion","volume":"46 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140839097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-04-30DOI: 10.1088/1361-6587/ad3eb1
V I Erofeev
In the comment to my recent work (Erofeev 2023 Plasma Phys. Control. Fusion65 085014) Chao Dong and Ding Li have pointed out a mistake that I missed in the last stage of my research (Dong and Li 2024 Plasma Phys. Control. Fusion66 068001). I will consider its essence and impact on the basic results reported in the paper in a slightly different way.
在对我最近的研究成果（Erofeev 2023 Plasma Phys. Control. Fusion65 085014）的评论中，董超（音译）和李丁（音译）指出了我在最后研究阶段（Dong and Li 2024 Plasma Phys. Control. Fusion66 068001）忽略的一个错误。我将以稍有不同的方式考虑其本质以及对论文中报告的基本结果的影响。
{"title":"Reply to Comment on ‘The influence of plasma evolution on a kinetic scenario of collisional relaxation of a magnetized plasma’","authors":"V I Erofeev","doi":"10.1088/1361-6587/ad3eb1","DOIUrl":"https://doi.org/10.1088/1361-6587/ad3eb1","url":null,"abstract":"In the comment to my recent work (Erofeev 2023 <italic toggle=\"yes\">Plasma Phys. Control. Fusion</italic>\u0000<bold>65</bold> 085014) Chao Dong and Ding Li have pointed out a mistake that I missed in the last stage of my research (Dong and Li 2024 <italic toggle=\"yes\">Plasma Phys. Control. Fusion</italic>\u0000<bold>66</bold> 068001). I will consider its essence and impact on the basic results reported in the paper in a slightly different way.","PeriodicalId":20239,"journal":{"name":"Plasma Physics and Controlled Fusion","volume":"31 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140839087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-04-24DOI: 10.1088/1361-6587/ad3f4b
Huasheng Xie and Xueyun Wang
Fusion reactivity represents the integration of fusion cross-sections and the velocity distributions of two reactants. In this study, we investigate the upper bound of fusion reactivity for a non-thermal reactant coexisting with a thermal Maxwellian background reactant while maintaining a constant total energy. Our optimization approach involves fine-tuning the velocity distribution of the non-thermal reactant. We employ both Lagrange multiplier and Monte Carlo methods to analyze Deuterium–Tritium (D–T) and proton-Boron11 (p-B11) fusion scenarios. Our findings demonstrate that, within the relevant range of fusion energy, the maximum fusion reactivity can often surpass that of the conventional Maxwellian–Maxwellian reactants case by a substantial margin, ranging from 50% to 300%. These enhancements are accompanied by distinctive distribution functions for the non-thermal reactant, characterized by one or multiple beams. These results not only establish an upper limit for fusion reactivity but also provide valuable insights into augmenting fusion reactivity through non-thermal fusion, which holds particular significance in the realm of fusion energy research.
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Pub Date : 2024-04-22DOI: 10.1088/1361-6587/ad3eb0
L M Pomârjanschi
The method of using neural networks (NNs) for turbulent transport prediction in a simplified model of tokamak plasmas is explored. The NNs are trained on a database obtained via test-particle simulations of a transport model in the slab-geometrical approximation. It consists of a five-dimensional input of transport model parameters, and the radial diffusion coefficient as output. The NNs display fast and efficient convergence, a validation error below 2 , and predictions in excellent agreement with the real data, obtained orders of magnitude faster than test-particle simulations. In comparison to a spline interpolation, the NN outperforms, exhibiting better predicting and extrapolating capabilities. We demonstrate the preciseness and efficiency of this method as a proof-of-concept, establishing a promising approach for future, more comprehensive research on the use of NNs for transport predictions in tokamak plasmas.
本文探讨了在托卡马克等离子体简化模型中使用神经网络（NN）进行湍流输运预测的方法。神经网络是在一个数据库上进行训练的，该数据库是通过对板状几何近似的输运模型进行测试粒子模拟而获得的。它由五维输运模型参数输入和径向扩散系数输出组成。网络显示出快速高效的收敛性，验证误差低于 2，预测结果与实际数据非常吻合，比测试粒子模拟快了几个数量级。与样条插值相比，NN 的性能更优越，具有更好的预测和外推能力。作为概念验证，我们证明了这种方法的精确性和高效性，为今后更全面地研究如何使用 NN 进行托卡马克等离子体中的输运预测提供了一种可行的方法。
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