Plasma Physics and Controlled Fusion最新文献

{"title":"Stability analysis of WEST L-mode discharges with improved confinement from boron powder injection","authors":"G Bodner, C Bourdelle, P Manas, A Gallo, K Afonin, A Diallo, R Lunsford, Ph Moreau, A Nagy, F Clairet, C Gil, E Tsitrone, L Vermare, the WEST Team4","doi":"10.1088/1361-6587/ad2c29","DOIUrl":"https://doi.org/10.1088/1361-6587/ad2c29","url":null,"abstract":"WEST L-mode plasmas with dominant electron heating and no core torque source have observed improvements in confinement during boron (B) powder injection. These results are reminiscent of previous powder injection experiments on other devices and gaseous impurity seeding experiments on WEST. During powder injection, the stored energy increased up to 25% due to enhanced ion and electron heat and particle confinement. The improvements in confinement were not indicative of an L-H transition. To identify the dominant mechanisms and the causality chain behind these improvements in confinement, we employ interpretative modeling using METIS, predictive integrated modeling using a high-fidelity plasma simulator (HFPS), and stand-alone gyrokinetic simulations using quasi-linear gyrokinetic code. Interpretative modeling with METIS allowed for the estimation of missing data while maintaining good overall consistency with experiment. These results provided the initial conditions for fully predictive flux driven simulations using the HFPS. From these simulations, quasi-linear gyrokinetic analysis was performed at <inline-formula>\u0000<tex-math><?CDATA $rho = 0.5$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mi>ρ</mml:mi><mml:mo>=</mml:mo><mml:mn>0.5</mml:mn></mml:math>\u0000<inline-graphic xlink:href=\"ppcfad2c29ieqn1.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> and <inline-formula>\u0000<tex-math><?CDATA $rho = 0.65$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mi>ρ</mml:mi><mml:mo>=</mml:mo><mml:mn>0.65</mml:mn></mml:math>\u0000<inline-graphic xlink:href=\"ppcfad2c29ieqn2.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula>. Collisionality was found to be a strong candidate for the turbulence suppression mechanism at <inline-formula>\u0000<tex-math><?CDATA $rho = 0.5$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mi>ρ</mml:mi><mml:mo>=</mml:mo><mml:mn>0.5</mml:mn></mml:math>\u0000<inline-graphic xlink:href=\"ppcfad2c29ieqn3.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula>, while a combination of collisionality and the <inline-formula>\u0000<tex-math><?CDATA ${T_e}/{T_{text{i}}}$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mrow><mml:msub><mml:mi>T</mml:mi><mml:mi>e</mml:mi></mml:msub></mml:mrow><mml:mrow><mml:mo>/</mml:mo></mml:mrow><mml:mrow><mml:msub><mml:mi>T</mml:mi><mml:mrow><mml:mtext>i</mml:mtext></mml:mrow></mml:msub></mml:mrow></mml:math>\u0000<inline-graphic xlink:href=\"ppcfad2c29ieqn4.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> ratio was found to be the likely mechanism at <inline-formula>\u0000<tex-math><?CDATA $rho = 0.65$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mi>ρ</mml:mi><mml:mo>=</mml:mo><mml:mn>0.65</mml:mn></mml:math>\u0000<inline-graphic xlink:href=\"ppcfad2c29ieqn5.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula>. The results additionally suggested that increased <inline-formula>\u0000<tex-math><?CDATA ${Z_{{text{eff}}}}$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mrow><mml:msub><mml:mi>Z</mml:mi><mml:mrow><mml:mrow><","PeriodicalId":20239,"journal":{"name":"Plasma Physics and Controlled Fusion","volume":"6 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140315207","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}

{"title":"A neoclassical validation of balanced and unbalanced rotations on EAST H-mode discharges","authors":"Cheonho Bae, Yifei Jin, Bo Lyu, Baolong Hao, Yingying Li, Xinjun Zhang, Haiqing Liu, Hongming Zhang, Fudi Wang, Jia Fu, Jing Fu, Juan Huang, Long Zeng, Qing Zang, Yichao Li, Liang He, Dian Lu","doi":"10.1088/1361-6587/ad2d66","DOIUrl":"https://doi.org/10.1088/1361-6587/ad2d66","url":null,"abstract":"Predicting residual stress (RS) contribution to intrinsic rotation is one of the major challenges in the study of momentum transport in tokamaks. One efficient experimental means of quantifying RS torque magnitude is to generate radially-flat and near-zero rotation profiles, termed ‘balanced rotations’ in this work, using counter-<italic toggle=\"yes\">I_p\u0000</italic> Neutral Beam Injections (NBIs) to effectively cancel the torques from co-<italic toggle=\"yes\">I_p\u0000</italic> NBIs. One remaining question, however, is on whether or not the attained velocity profile is well zeroed and flat enough so that the predicted RS torques based on perfect balance assumption can be used for further studies such as fitting of diffusive and convective coefficients to match with experiments. This article presents a neoclassical means of validating the attained balanced and unbalanced rotations at EAST to consequently validate the predicted RS torque profiles, using TRANSP/NUBEAM and a recently-developed neoclassical rotation/transport code TransROTA (Bae <italic toggle=\"yes\">et al</italic> 2024 <italic toggle=\"yes\">Comput. Phys. Commun.</italic>\u0000<bold>296</bold> 108992). Both balanced and unbalanced EAST H-mode discharges are analyzed to find that the suggested neoclassical validation methodology successfully validates attained balanced rotations. It also finds that neoclassical gyroviscous (NGV) torque serves as the balance-breaking mechanism for axisymmetric plasmas and the balance-breakings start from the core and propagate towards the edge. This work also suggests the possibility of using the neoclassical methodology to find locally-balanced rotations at an elevated velocity range near ∼20 km s⁻¹, which implies possible scaling of RS torques up to a certain elevated velocity range.","PeriodicalId":20239,"journal":{"name":"Plasma Physics and Controlled Fusion","volume":"202 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140315333","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}

{"title":"NBI optimization on SMART and implications for scenario development","authors":"M Podestà, D J Cruz-Zabala, F M Poli, J Dominguez-Palacios, J W Berkery, M Garcia-Muñoz, E Viezzer, A Mancini, J Segado, L Velarde, S M Kaye","doi":"10.1088/1361-6587/ad2edc","DOIUrl":"https://doi.org/10.1088/1361-6587/ad2edc","url":null,"abstract":"The SMall Aspect Ratio Tokamak (SMART) under commissioning at the University of Seville, Spain, aims to explore confinement properties and possible advantages in confinement for compact/spherical tokamaks operating at negative vs. positive triangularity. This work explores the benefits of auxiliary heating through Neutral Beam Injection (NBI) for SMART scenarios beyond the initial Ohmic phase of operations, in support of the device’s mission. Expected values of electron and ion temperature achievable with NBI heating are first predicted for the current flat-top phase, including modeling to optimize the NBI injection geometry to maximize NBI absorption and minimize losses for a given equilibrium. Simulations are then extended for a selected case to cover the current ramp-up phase. Differences with results obtained for the flat-top phase indicate the importance of determining the plasma evolution over time, as well as self-consistently determining the edge plasma parameters for reliable time-dependent simulations. Initial simulation results indicate the advantage of auxiliary NBI heating to achieve nearly double values of pressure and stored energy compared to Ohmic discharges, thus significantly increasing the device’s performance. The scenarios developed in this work will also contribute to diagnostic development and optimization for SMART, as well as providing test cases for initial predictions of macro- and micro-instabilities.","PeriodicalId":20239,"journal":{"name":"Plasma Physics and Controlled Fusion","volume":"152 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140315104","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}

{"title":"Flow-shear destabilization of multiscale electron turbulence","authors":"E A Belli, J Candy, I Sfiligoi","doi":"10.1088/1361-6587/ad2c28","DOIUrl":"https://doi.org/10.1088/1361-6587/ad2c28","url":null,"abstract":"The impact of sheared <inline-formula>\u0000<tex-math><?CDATA ${mathbf{E} hskip -1pt times hskip -1pt mathbf{B}}$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mrow><mml:mrow><mml:mi mathvariant=\"bold\">E</mml:mi></mml:mrow><mml:mo>×</mml:mo><mml:mrow><mml:mi mathvariant=\"bold\">B</mml:mi></mml:mrow></mml:mrow></mml:math>\u0000<inline-graphic xlink:href=\"ppcfad2c28ieqn1.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> flow on multiscale turbulence is studied with nonlinear gyrokinetic simulations. Simulations are based on DIII-D-like, high-confinement mode (H-mode) pedestal parameters in the regime of low ion temperature gradient drive, where there is a broad spectrum of electron temperature gradient (ETG)-driven turbulence. It is found that <inline-formula>\u0000<tex-math><?CDATA ${mathbf{E} hskip -1pt times hskip -1pt mathbf{B}}$?></tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mrow><mml:mrow><mml:mi mathvariant=\"bold\">E</mml:mi></mml:mrow><mml:mo>×</mml:mo><mml:mrow><mml:mi mathvariant=\"bold\">B</mml:mi></mml:mrow></mml:mrow></mml:math>\u0000<inline-graphic xlink:href=\"ppcfad2c28ieqn2.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> shear can have a significant effect on ETG-driven electron transport, with an unexpected transition from a turbulence stabilization regime at moderate to large shearing rates <italic toggle=\"yes\">γ</italic>\u0000_{\u0000<italic toggle=\"yes\">E</italic>\u0000} to a novel turbulence destabilization regime at low levels of <italic toggle=\"yes\">γ</italic>\u0000_{\u0000<italic toggle=\"yes\">E</italic>\u0000}. In the turbulence stabilization regime, the electron energy flux decreases monotonically with <italic toggle=\"yes\">γ</italic>\u0000_{\u0000<italic toggle=\"yes\">E</italic>\u0000}, even when <italic toggle=\"yes\">γ</italic>\u0000_{\u0000<italic toggle=\"yes\">E</italic>\u0000} is small compared to electron mode growth rates. The stabilizing effect comes dominantly from the electron, not ion, gyrokinetic equation. In the novel destabilization regime, reduction of zonal energy results from the interaction of <italic toggle=\"yes\">γ</italic>\u0000_{\u0000<italic toggle=\"yes\">E</italic>\u0000}-modulated nonlinear drive in the zonal ion gyrokinetic equation, increasing the electron transport over a broad range of shearing rates. Neither of these effects have been observed in previous electron-scale simulations.","PeriodicalId":20239,"journal":{"name":"Plasma Physics and Controlled Fusion","volume":"40 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140315199","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}

{"title":"Comparison of electron temperature and density measured by helium line intensity ratio and Thomson scattering methods in ECH spherical tokamak plasma","authors":"Takumi Komiyama, Taiichi Shikama, Kazuaki Hanada, Takeshi Ido, Takumi Onchi, Kaori Kono, Akira Ejiri, Makoto Hasegawa, Satoshi Inoue, Masahiro Hasuo, Hiroshi Idei, Qilin Yue, Kengo Kuroda, Aki Higashijima, Pakkapawn Prapan","doi":"10.1088/1361-6587/ad2c2a","DOIUrl":"https://doi.org/10.1088/1361-6587/ad2c2a","url":null,"abstract":"The electron temperature and density profiles in the midplane of a spherical tokamak plasma produced by electron cyclotron heating (ECH) in Q-shu University experiment with steady-state spherical tokamak (QUEST) are measured by the helium line intensity ratio method. The measured profiles are compared with those obtained by the Thomson scattering method, and the measured temperatures and densities are found to agree within factors of ∼2 and ∼6, respectively. Taken together with the previous results of comparisons performed in the scrape-off layers of several toroidal devices, the same degree of agreement between the helium line intensity ratio method and other methods is obtained in the ranges of 7–100 eV for temperature and 4 × 10¹⁶–1 × 10¹⁹ m⁻³ for density.","PeriodicalId":20239,"journal":{"name":"Plasma Physics and Controlled Fusion","volume":"159 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140315203","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}

{"title":"Magnetics only real-time equilibrium reconstruction on ASDEX Upgrade","authors":"L Giannone, M Weiland, R Fischer, O Kudlacek, T Lunt, M Maraschek, B Sieglin, W Suttrop, G Conway, M Dunne, E Fable, J C Fuchs, A Gude, V Igochine, P J McCarthy, R McDermott, the ASDEX Upgrade Team1","doi":"10.1088/1361-6587/ad2c2b","DOIUrl":"https://doi.org/10.1088/1361-6587/ad2c2b","url":null,"abstract":"Real-time reconstruction of the magnetic equilibrium provides fundamental control of plasma shape and position in a tokamak. Details of the implementation of the equilibrium reconstruction code developed for the ASDEX Upgrade tokamak (JANET++) are summarized. Cubic Hermite splines are introduced as current density basis functions for solving the Grad–Shafranov equation. The choice of the optimal Tikhonov regularization parameter is discussed. The code is validated by comparing the results of the equilibrium reconstruction with those of further equilibrium reconstructions available on ASDEX Upgrade (CLISTE and IDE). In a high time resolution study of a discharge with edge localized modes (ELM), the poloidal asymmetry of the fits and magnetic probe measurements suggest that the real-time equilibrium reconstruction captures the essential features of the current density redistribution in an ELMing edge plasma. An efficient algorithm to locate multiple X-points and identify the active one in advanced X-divertor and snowflake divertor configurations is presented.","PeriodicalId":20239,"journal":{"name":"Plasma Physics and Controlled Fusion","volume":"40 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140315360","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}

{"title":"Theoretical analysis of perturbative high harmonic wave mixing from plasma surfaces","authors":"Fan Xia, Haocheng Tang, Weiqi Tang, Zihang Wen, Zhengyan Li","doi":"10.1088/1361-6587/ad2c2c","DOIUrl":"https://doi.org/10.1088/1361-6587/ad2c2c","url":null,"abstract":"High harmonic generation modulated by a weakly perturbing laser field enables new wave mixing frequency components, thus allowing <italic toggle=\"yes\">in-situ</italic> spatiotemporal measurements and wavefront control of attosecond optical pulses. However, perturbative high harmonic wave mixing from plasma surfaces has not been investigated extensively. In this study, we theoretically analyze the plasma high harmonic generation process in the relativistic regime modulated by a perturbing laser field with an arbitrary frequency. New wave mixing frequency components satisfying the conservation laws of photon energy and momentum are observed. The wave mixing component intensities adhere to a power law for the perturbating laser photon number as the perturbing laser intensity increases, thereby revealing perturbative behaviors in the nonperturbative, extremely nonlinear optical process of high harmonic generation. Detailed studies reveal the polarization selection rule and physical mechanism of high harmonic wave mixing. The modulation of the relativistic factor or mass enhancement of electrons on the plasma surface by the perturbing laser field is believed to result in high harmonic wave mixing in the relativistic regime.","PeriodicalId":20239,"journal":{"name":"Plasma Physics and Controlled Fusion","volume":"3 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140315325","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}

{"title":"Hall physics during magnetic reconnection with collision effect","authors":"Yukang Shu, San Lu, Quanming Lu, Kai Huang, Rongsheng Wang, Weixing Ding","doi":"10.1088/1361-6587/ad2b8f","DOIUrl":"https://doi.org/10.1088/1361-6587/ad2b8f","url":null,"abstract":"The Hall effect, decoupling between the ion and electron motions, is the core mechanism triggering fast reconnection. In plasmas with collision effects such as laboratory facilities, collision can suppress the Hall effect and influence the triggering of fast reconnection. Here, by conducting a series of kinetic simulations with varying collision parameters, we show that collisions can suppress the electron outflow, impairing the quadrupole Hall magnetic field. Besides, collision weakens the inflow of magnetic flux by reducing the charge separation and increasing the thermal pressure at the reconnection site, leading to a reduction of the Hall electric field. As the collisionality becomes larger, the Hall electric field diminishes more easily than the Hall magnetic field. We propose that the quadrupolar Hall magnetic field can be a significant indicator in reflecting Hall reconnection.","PeriodicalId":20239,"journal":{"name":"Plasma Physics and Controlled Fusion","volume":"14 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140315259","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}

{"title":"Observation of the low electron density and electron temperature in an unmagnetized cascaded arc helium plasma by laser Thomson scattering approach","authors":"Yong Wang, Lina Zhou, Jielin Shi, Yu Li, Cong Li, Chunlei Feng, Hongbin Ding","doi":"10.1088/1361-6587/ad2b8e","DOIUrl":"https://doi.org/10.1088/1361-6587/ad2b8e","url":null,"abstract":"In this study, the electron density (<italic toggle=\"yes\">n_e\u0000</italic>) and temperature (<italic toggle=\"yes\">T_e\u0000</italic>) in an unmagnetized cascaded arc helium (He) plasma are precisely determined using cutting-edge laser Thomson scattering. In our experimental scope, <italic toggle=\"yes\">n_e\u0000</italic> is only 10¹⁸ m⁻³ and <italic toggle=\"yes\">T_e\u0000</italic> is less than 0.2 eV, both of which are substantially lower than in linear plasma devices (LPDs). The comparison of <italic toggle=\"yes\">n_e\u0000</italic> and <italic toggle=\"yes\">T_e\u0000</italic> values in He plasma with those in cascaded arc Ar plasma reveals that these two parameters are likewise significantly lower in He plasma than they are in Ar plasma on average. In comparison to Ar gas, the degree of ionization of He is low due to its high ionization potential, and diffusive loss dominates due to its light weight, both of which result in a lower <italic toggle=\"yes\">n_e\u0000</italic>. Meanwhile, these two characteristics render the three-body recombination interaction between electrons and He⁺ ions in He plasma insignificant, thus the electrons cannot be heated effectively, explaining why <italic toggle=\"yes\">T_e\u0000</italic> is lower. This study will provide foundational data and build the groundwork for a thorough knowledge of cascaded arc He plasma in LPDs and plasma windows.","PeriodicalId":20239,"journal":{"name":"Plasma Physics and Controlled Fusion","volume":"39 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140315619","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}

{"title":"Reversed-direction 2-point modelling applied to divertor conditions in DIII-D *","authors":"J H Nichols, P C Stangeby, A G McLean, J M Canik, A L Moser, M W Shafer, H Q Wang","doi":"10.1088/1361-6587/ad2b90","DOIUrl":"https://doi.org/10.1088/1361-6587/ad2b90","url":null,"abstract":"A predictive form of the extended 2-point model known as the ‘reverse 2-point model’, Rev2PM, is applied to a range of detachment levels in the open lower divertor of DIII-D, showing that the experimentally measured electron temperature (<italic toggle=\"yes\">T_e\u0000</italic>) and pressure (<italic toggle=\"yes\">p_e\u0000</italic>) at the divertor entrance can be calculated within 50% from target measurements, if and only if <italic toggle=\"yes\">a posteriori</italic> corrections for convective heat flux are included in the model. Unlike the standard 2-point model, the Rev2PM calculates upstream scrape-off layer (SOL) quantities (such as separatrix <italic toggle=\"yes\">T_e\u0000</italic> and <italic toggle=\"yes\">p_e\u0000</italic>) from target conditions (such as <italic toggle=\"yes\">T_e\u0000</italic> and parallel heat flux), with volumetric power and momentum losses depending solely on target <italic toggle=\"yes\">T_e\u0000</italic>. The Rev2PM is tested against a database of DIII-D inter-ELM divertor Thomson scattering measurements, built from a series of 6 MW, 1.3 MA, LSN H-mode discharges with varied main ion density, drift direction, and nitrogen puffing rate. Measured target <italic toggle=\"yes\">T_e\u0000</italic> ranged from 0.4–25 eV over this database, and upstream <italic toggle=\"yes\">T_e\u0000</italic> ranged from 5–60 eV. Poor agreement is found between upstream measurements and Rev2PM calculations that assume purely conductive parallel heat transport. However, introducing <italic toggle=\"yes\">a posteriori</italic> corrections to account for convective heat transport brings the Rev2PM calculations within 50% of the measured upstream values across the dataset. These corrections imply that up to 99% of the parallel heat flux is carried by convection in detached conditions in the DIII-D open lower divertor, though further work is required to assess any potential dependencies on device size or divertor closure.","PeriodicalId":20239,"journal":{"name":"Plasma Physics and Controlled Fusion","volume":"44 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140315205","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}