Article
Physics, Fluids & Plasmas
A. Mathews, N. Mandell, M. Francisquez, J. W. Hughes, A. Hakim
Summary: The study compared turbulent field fluctuations between electrostatic two-fluid theory and electromagnetic gyrokinetic modeling using a novel physics-informed deep learning framework, finding good overall agreement in magnetized helical plasmas at low normalized pressure. This technique presents a new approach for the numerical validation and discovery of reduced global plasma turbulence models.
PHYSICS OF PLASMAS
(2021)
Article
Physics, Fluids & Plasmas
A. Dudkovskaia, H. R. Wilson, J. W. Connor, D. Dickinson, F. Parra
Summary: The steep plasma pressure gradient at the edge of the high confinement H-mode regime of tokamak operation drives electromagnetic micro-instabilities in the pedestal region. This pressure gradient also influences the stability of ballooning and kink modes and affects confinement in future tokamak power plants. Conventional gyrokinetic theory is extended to incorporate neoclassical effects and provide a model that captures the consequences of large bootstrap current fractions.
PLASMA PHYSICS AND CONTROLLED FUSION
(2023)
Article
Physics, Multidisciplinary
Jeongwon Lee, Hyun-Tae Kim, Jayhyun Kim, Sang-hee Hahn, June-Woo Juhn, JuHyuk Jang, Jun-Gyo Bak, SooHyun Son, Mi Jung, YoungHwa An, Yong-Su Na, Si-Woo Yoon
Summary: An electron cyclotron heating (ECH) power absorption model, DYON-EC, was developed and validated against KSTAR ECH-assist start-up experiments. The absorbed ECH power was calculated based on electron density, temperature, and hardware settings, with consideration of wave parameter changes due to wall reflection. The DYON-EC model successfully reproduced multiple KSTAR EC-assisted discharges using optimized simulation settings, confirming its validity.
Article
Physics, Multidisciplinary
Aristeides D. Papadopoulos, Johan Anderson, Eun-jin Kim, Michail Mavridis, Heinz Isliker
Summary: A geometrical method for assessing stochastic processes in plasma turbulence is investigated, using a Riemannian metric on the phase space to compute distances between thermodynamic states. This method provides a geometric approach to understand stochastic processes, such as order-disorder transitions. The study focuses on gyrokinetic simulations of ion-temperature-gradient (ITG)-mode-driven turbulence in the W7-X stellarator.
Article
Acoustics
Jeremie Vidal, David Cebron
Summary: Using the acoustic modes of a rotating fluid-filled cavity can determine the effective rotation rate of a fluid, requiring a prior knowledge of the acoustic modes in rotating fluids for accuracy. Unlike the Coriolis force, centrifugal gravity has received less attention in experiments. This study investigates how global rotation and buoyancy modify the acoustic modes of fluid-filled ellipsoids in hydrostatic equilibrium.
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
(2021)
Article
Physics, Fluids & Plasmas
T. N. Bernard, F. D. Halpern, M. Francisquez, N. R. Mandell, J. Juno, G. W. Hammett, A. Hakim, G. J. Wilkie, J. Guterl
Summary: This study presents the novel coupling of a continuum full-F gyrokinetic turbulence model with a 6D continuum model for kinetic neutrals using the Gkeyll code. The aim is to improve the understanding of the role of neutrals in plasma fueling, detachment, and their interaction with edge plasma profiles and turbulence statistics.
PHYSICS OF PLASMAS
(2022)
Article
Physics, Fluids & Plasmas
T. Rubin, J. M. Rax, N. J. Fisch
Summary: A new method for end-plugging in rotating plasmas is discovered, utilizing the ponderomotive potential of an azimuthal magnetostatic wiggler. Through analytical and numerical analysis, this approach is found to be favorable compared to other end-plugging methods in magnetized plasma devices with open field lines.
PHYSICS OF PLASMAS
(2023)
Article
Multidisciplinary Sciences
Hidemoto Satake, Toshio Tagawa
Summary: In this study, we analyzed thermal convection in a rotating spherical shell and investigated the effects of centrifugal buoyancy on the convection structure. It was found that as the effect of centrifugal buoyancy increases, axisymmetric flow tends to be maintained.
Article
Physics, Fluids & Plasmas
S. Aggarwal, Y. Camenen, A. Escarguel, A. Poye
Summary: A two-fluid model is used to investigate the stability of weakly magnetized rotating plasma columns, which are prone to centrifugal flute modes. Previous models based on low-frequency assumption are not applicable in laboratory plasma devices, including weakly magnetized plasma columns. Thus, a radially global dispersion relation is derived to relax the low-frequency approximation and investigate linear stability in these devices. The impact of the radial boundary on stability is also examined and compared with results obtained in the radially local approximation.
JOURNAL OF PLASMA PHYSICS
(2023)
Article
Physics, Fluids & Plasmas
Philipp Ulbl, Thomas Body, Wladimir Zholobenko, Andreas Stegmeir, Jan Pfennig, Frank Jenko
Summary: Understanding and predicting turbulent transport in fusion devices' edge and scrape-off layer is crucial. The latest improvements to the GENE-X turbulence code are validated against experimental results in the TCV tokamak. GENE-X features a full-f electromagnetic gyrokinetic model and can model collisions using either a basic BGK or a more sophisticated LBD collision operator. The accuracy of the collision model significantly improves the match to experimental measurements.
PHYSICS OF PLASMAS
(2023)
Article
Physics, Applied
Pascal Brault, Mado Abraham, Aida Bensebaa, Olivier Aubry, Dunpin Hong, Herve Rabat, Monica Magureanu
Summary: The study found that a local temperature of 2500 K is required to decompose paracetamol to CO, H2O, NH3, and C2H2 in the presence of 10% hydroxyl radicals in water.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Physics, Fluids & Plasmas
Zhixin Lu, Guo Meng, Roman Hatzky, Matthias Hoelzl, Philipp Lauber
Summary: This work focuses on developing and applying the particle-in-cell scheme to study Alfven waves and energetic particle (EP) physics in tokamak plasmas. Both delta f and full f schemes are formulated using mixed variables and the pullback scheme. The TRIMEG-GKX code is upgraded with cubic spline finite elements and both full f and delta f schemes. The simulations demonstrate the good agreement of the delta f scheme with previous work and the excellent performance of the mixed variable/pullback scheme in mitigating noise levels. The full f scheme provides a powerful tool for studying EP physics with realistic experimental distributions.
PLASMA PHYSICS AND CONTROLLED FUSION
(2023)
Article
Physics, Multidisciplinary
Bivash Dolai, Ram Prasad Prajapati
Summary: This study investigates the velocity shear driven Kelvin-Helmholtz (K-H) instability in an incompressible subsonic sheared dusty plasma. The results show that the simultaneous presence of ion drag and dust polarization forces excites the K-H instability, which is completely suppressed in the absence of these forces. The magnitude of the shear velocity increase and the dust polarization interaction parameter enhance the growth rate of the instability.
Article
Education, Scientific Disciplines
Elmo Benedetto, Marco Di Mauro, Antonio Feoli, Antonella Lucia Iannella, Adele Naddeo
Summary: During general relativity courses, the frame-dragging effect is explained by emphasizing the presence of a gravitational Coriolis-like force term. However, textbooks often neglect the possibility of a gravitational centrifugal-like force. This paper aims to analyze this additional gravitational term, providing valuable insights for undergraduate courses on general relativity.
EUROPEAN JOURNAL OF PHYSICS
(2023)
Article
Physics, Fluids & Plasmas
Junhyuk Song, Carlos Paz-Soldan, Jungpyo Lee
Summary: The axisymmetric (n=0) resistive wall mode instability in negative triangularity plasma shape is influenced by plasma characteristics and geometric effects, with higher poloidal beta leading to more instability in negative triangularity compared to positive triangularity. Non-conformal wall shapes have been found to be helpful in stabilizing the n=0 mode, unless the plasma is too close to the walls at the nulls for the opposite triangularity.
Article
Physics, Fluids & Plasmas
S. Mazzi, Y. Camenen, J. Garcia, D. Zarzoso, D. Frigione, L. Garzotti, F. Rimini, D. Van Eester
Summary: The impact of parallel flow shear on the stability and turbulent transport of tokamak plasma driven by ion temperature gradient modes has been analyzed using local gyrokinetic numerical simulations. It was found that parallel flow shear increases the growth rate of ion temperature gradient modes in the linear regime and causes broadening and shifting of the radial spectrum. Nonlinear effects of finite parallel shear on turbulent characteristics were also studied, showing that it reduces the thermal ion turbulent heat flux through the nonlinear generation of enhanced zonal flow activity.
Article
Physics, Fluids & Plasmas
H. G. Dudding, F. J. Casson, D. Dickinson, B. S. Patel, C. M. Roach, E. A. Belli, G. M. Staebler
Summary: The new SAT3 model can better reproduce the isotope mass dependence of nonlinear gyrokinetic fluxes compared to contemporary models, while performing at least as well in other key equilibrium parameters. The formulation of SAT3 is based on observations from gyrokinetic data including a novel and robust relation between the 1D potential spectrum and the radial spectral widths.
Article
Physics, Fluids & Plasmas
Hyun-Tae Kim, Francis Casson, Hendrik Meyer, Geof Cunningham, Rory Scannell, Lucy Kogan, James Harrison, Seong-Cheol Kim, Jin-Woo Gwak, Yong-Su Na, Jeong-Won Lee, Xavier Litaudon, Gloria Falchetto
Summary: The paper presents an improved electromagnetic plasma burn-through model, which accurately calculates the time-evolving parameters of plasma based on control room operation signals, showing a reasonable level of agreement with experimental measurement.
Article
Physics, Fluids & Plasmas
A. R. Field, F. J. Casson, D. Fajardo, C. Angioni, C. D. Challis, J. Hobirk, A. Kappatou, Hyun-Tae Kim, E. Lerche, A. Loarte, J. Mailloux
Summary: Screening of high-Z (W) impurities from the plasma periphery by temperature gradient has been demonstrated in the JET-ILW tokamak. Careful optimization of the hybrid scenario allows for the expulsion of W impurities from the confined plasma, resulting in sustained high performance. Measurements show a net efflux of impurities between edge-localised modes (ELMs), with some W re-entering during ELMs.
Article
Physics, Fluids & Plasmas
M. Marin, J. Citrin, C. Giroud, C. Bourdelle, Y. Camenen, L. Garzotti, A. Ho, M. Sertoli
Summary: Nuclear fusion reactor plasmas need to release a significant amount of energy through radiation for acceptable divertor loads. Impurities injected from the plasma edge can provide this through line radiation. However, there are limitations on the sustainable impurity content due to deleterious effects on electron heat sink and fuel availability. Recent experiments at JET show that neon-seeded discharges improve plasma confinement compared to purer plasmas, and this improvement is explained by higher pedestal temperature, increased rotation shear, and impurity-induced microturbulence stabilization.
Article
Physics, Fluids & Plasmas
D. Fajardo, C. Angioni, F. J. Casson, A. R. Field, P. Maget, P. Manas
Summary: The impact of rotation, collisionality, and trapped particle fraction on neoclassical impurity transport in tokamaks is studied. The study reveals that at high Mach number and low collisionality, a window of operation opens where the impurity temperature screening effect increases with rotation. However, with increasing collisionality, this effect diminishes and the temperature gradient drives an inward impurity flux in the presence of rotation. The boundaries between these regimes are calculated and plasma parameters achieved in recent experiments are found to access the beneficial regime.
PLASMA PHYSICS AND CONTROLLED FUSION
(2023)
Article
Physics, Fluids & Plasmas
S. Aggarwal, Y. Camenen, A. Escarguel, A. Poye
Summary: A two-fluid model is used to investigate the stability of weakly magnetized rotating plasma columns, which are prone to centrifugal flute modes. Previous models based on low-frequency assumption are not applicable in laboratory plasma devices, including weakly magnetized plasma columns. Thus, a radially global dispersion relation is derived to relax the low-frequency approximation and investigate linear stability in these devices. The impact of the radial boundary on stability is also examined and compared with results obtained in the radially local approximation.
JOURNAL OF PLASMA PHYSICS
(2023)
Article
Physics, Fluids & Plasmas
A. Ho, J. Citrin, C. D. Challis, C. Bourdelle, F. J. Casson, J. Garcia, J. Hobirk, A. Kappatou, D. L. Keeling, D. B. King, F. Koechl, E. Lerche, C. F. Maggi, J. Mailloux
Summary: This study applies the coupled JINTRAC and QuaLiKiz-neural-network (QLKNN) model to investigate the ohmic current ramp-up phase of a JET D discharge. It reveals the role of transport on the Te hollowing, which is caused by the isotope effect on the electron-ion energy exchange. The study demonstrates the potential of neural network surrogates for fast routine analysis and discharge design, but discrepancies between QuaLiKiz and QLKNN impurity transport behavior were found, suggesting further investigation into the turbulent component of heavy impurity transport.
Article
Physics, Fluids & Plasmas
C. Bourdelle, J. Morales, J. F. Artaud, O. Grover, T. Radenac, J. Bucalossi, Y. Camenen, G. Ciraolo, F. Clairet, R. Dumont, N. Fedorczak, J. Gaspar, C. Gil, M. Goniche, C. Guillemaut, J. Gunn, P. Maget, P. Manas, V. Ostuni, B. Pegourie, Y. Peysson, P. Tamain, L. Vermare, D. Vezinet
Summary: WEST database analysis questions the causality chain between particle source and turbulent transport in L-mode, high recycling plasmas, based on the correlation between recycled neutral source around the separatrix and core performances.
Article
Physics, Fluids & Plasmas
M. Hamed, M. J. Pueschel, J. Citrin, M. Muraglia, X. Garbet, Y. Camenen
Summary: The magnetic drift and theelectric potential affect the growth rate of microtearing instability andturbulent saturation. The Rechester-Rosenbluth model predicts electron heatdiffusivity by microtearing turbulence accurately. Nonlinear gyrokineticflux-tube simulations show that zonal flows and fields influence thesaturation mechanism and heat fluxes in tokamak plasmas.
PHYSICS OF PLASMAS
(2023)
Article
Physics, Fluids & Plasmas
C. Gillot, G. Dif-Pradalier, Y. Sarazin, C. Bourdelle, A. Banon Navarro, Y. Camenen, J. Citrin, A. Di Siena, X. Garbet, Ph Ghendrih, V Grandgirard, P. Manas, F. Widmer
Summary: This study compares reduced quasilinear and nonlinear models with scale separations to nonlinear models without scale separations by using Boltzmann electrons. The success of the reduced models lies in their ability to reproduce nonlinear fluxes. However, the reduced models significantly underestimate fluxes near marginal stability, ignoring mesoscale flow organization and turbulence self-advection. Constructive suggestions to improve the reduced models are discussed.
PLASMA PHYSICS AND CONTROLLED FUSION
(2023)
Article
Physics, Fluids & Plasmas
D. Kennedy, M. Giacomin, F. J. Casson, D. Dickinson, W. A. Hornsby, B. S. Patel, C. M. Roach
Summary: In this study, a linear gyrokinetic analysis is conducted to investigate the electromagnetic microinstabilities in a high-beta, reactor-scale, tight-aspect-ratio tokamak called Spherical Tokamak for Energy Production. The results reveal that the dominant instabilities at ion binormal scales are a hybrid version of the kinetic ballooning mode (KBM) instability, with contributions from the ion temperature gradient and trapped electrons, while collisional microtearing modes (MTMs) are sub-dominantly unstable at similar scales. The different radial scales of the hybrid-KBM and MTM are also observed. The study examines the sensitivity of these instabilities to physics parameters and discusses potential mitigation mechanisms. Benchmarking and testing with multiple gyrokinetic codes provide confidence in the accuracy of the results, setting the stage for further nonlinear studies in future research.
Article
Physics, Fluids & Plasmas
S. Gabriellini, L. Garzotti, V. K. Zotta, C. Bourdelle, F. J. Casson, J. Citrin, D. Frigione, R. Gatto, C. Giroud, F. Koechl, P. Lomas, M. Marin, S. Menmuir, G. Pucella, F. Rimini, D. van Eester, JET Contributors
Summary: We present a fully predictive modelling of two JET-ILW high-performance baseline plasmas, comparing a Ne seeded shot and an equivalent unseeded one. The results suggest that the improved performance of the Ne seeded shot is due to a combination of turbulence stabilization and improved pedestal parameters.
Article
Physics, Fluids & Plasmas
J. Garcia, F. J. Casson, L. Frassinetti, D. Gallart, L. Garzotti, H. -t. Kim, M. Nocente, S. Saarelma, F. Auriemma, J. Ferreira, S. Gabriellini, A. Ho, P. Huynh, K. K. Kirov, E. Lerche, M. J. Mantsinen, V. K. Zotta, Z. Stancar, D. M. A. Taylor, D. Van Eester, C. D. Challis, JET Contributors
Summary: For more than a decade, an unprecedented predict-first activity has been carried out to predict fusion power and provide guidance to the DTE2 campaign. It is shown that detailed physics-based predictions are necessary and a combination of different modeling complexities and an extended interplay between modeling and experiment are essential for reliable predictions of D-T plasmas.
Article
Physics, Fluids & Plasmas
Hyun-Tae Kim, Fulvio Auriemma, Jorge Ferreira, Stefano Gabriellini, Aaron Ho, Philippe Huynh, Krassimir Kirov, Rita Lorenzini, Michele Marin, Michal Poradzinski, Nan Shi, Gary Staebler, Ziga Stancar, Gediminas Stankunas, Vito Konrad Zotta, Emily Belli, Francis J. Casson, Clive Challis, Jonathan Citrin, Dirk van Eester, Emil Fransson, Daniel Gallart, Jeronimo Garcia, Luca Garzotti, Renato Gatto, Joerg Hobirk, Athina Kappatou, Ernesto Lerche, Andrei Ludvig-Osipov, Costanza Maggi, Mikhail Maslov, Massimo Nocente, Ridhima Sharma, Alessandro Di Siena, Par Strand, Emmi Tholerus, Dimitriy Yadykin
Summary: The JET experiments provide an opportunity to validate D-T fusion power predictions and support future device design and operation preparation. The core integrated modelling with TRANSP, JINTRAC, and ETS coupled with a quasilinear turbulent transport model was validated against the measured data in 2021 JET D-T discharges. The good statistical agreement confirms the accuracy of D-T fusion power calculations, and similarities were found between the predictive modelling of D-T and counterpart D discharges.
