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
J. E. Rice, C. Angioni, N. M. Cao, M. L. Reinke
Summary: The behavior of core and molybdenum ions in tokamak plasmas has been compared under different operating conditions and confinement schemes. The velocities of the two impurities are found to be nearly identical, in agreement with the predictions of neo-classical theory.
Article
Physics, Fluids & Plasmas
Harshita Raj, C. Theiler, A. Thornton, O. Fevrier, S. Gorno, F. Bagnato, P. Blanchard, C. Colandrea, H. de Oliveira, B. P. Duval, B. Labit, A. Perek, H. Reimerdes, U. Sheikh, M. Vallar, B. Vincent
Summary: Nitrogen seeded detachment has been achieved in different divertor configurations in the tokamak a configuration variable, leading to a remarkable reduction in heat fluxes to the target.
Article
Physics, Fluids & Plasmas
A. M. Garofalo, S. Ding, W. M. Solomon, B. A. Grierson, X. Jian, T. H. Osborne, C. Holland, M. Knolker, F. M. Laggner, C. Chrystal, A. Marinoni, C. C. Petty
Summary: Analysis of experiments on DIII-D and modeling results show that high plasma toroidal rotation plays a key role in achieving high energy confinement quality, rather than high pedestal. Experimental and modeling results indicate that high rotation shear discharges have high levels of H(98y2), independent of pedestal height, while high pedestal discharges with low rotation shear have levels of H(98y2) only slightly above 1. The toroidal rotation shear, which varies with the level of injected neutral beam torque per particle, mainly determines the energy confinement quality.
Article
Physics, Fluids & Plasmas
L. Horvath, C. F. Maggi, A. Chankin, S. Saarelma, A. R. Field, S. Aleiferis, E. Belonohy, A. Boboc, G. Corrigan, E. G. Delabie, J. Flanagan, L. Frassinetti, C. Giroud, D. Harting, D. Keeling, D. King, M. Maslov, G. F. Matthews, S. Menmuir, S. A. Silburn, J. Simpson, A. C. C. Sips, H. Weisen, K. J. Gibson
Summary: In a series of JET experiments with ITER-like wall hydrogen (H) and deuterium (D) plasmas, it was found that the pedestal pressure is typically higher in D than in H, requiring higher inter-ELM separatrix loss power in H to maintain a similar pedestal top pressure. Additionally, higher edge particle and heat transport coefficients are needed in H than in D to match the experimental profiles. The difference in neutral penetration between H and D has minor effects on upstream density profiles, with H potentially requiring higher input power for similar stored energy.
Article
Physics, Fluids & Plasmas
Y. Q. Chu, B. S. Zhang, P. Li, X. D. Yang, H. Q. Liu, Y. X. Jie, C. B. Wu, W. M. Zhang, K. D. Li, T. F. Zhou, L. He, Q. Zang, H. Lian, F. B. Zhong, R. J. Zhu, L. F. Zhang, K. Hanada
Summary: Improved confinement caused by Ne injection is investigated in EAST. The safety factor q profile and electron-scale turbulence are studied with a polarimeter-interferometer system and CO2 laser collective scattering system in a series of Ne injection experiments in EAST. Ne with a suitable injection rate can lead to negative magnetic shear in the plasma core, which promotes electron-scale turbulence suppression. The continuous injection of Ne under the reversed shear condition further reduces the electron-scale turbulence intensity. Core electron temperature increase and confinement improvement are observed.
Article
Physics, Fluids & Plasmas
P. Cano-Megias, E. Viezzer, J. Galdon-Quiroga, L. Sanchis, M. Garcia-Munoz, D. J. Cruz-Zabala, R. M. McDermott, J. F. Rivero-Rodriguez, A. Snicker, W. A. Suttrop, M. Willensdorfer
Summary: This paper studies the effect of 3D magnetic perturbations on fast-ion confinement and the toroidal rotation velocity profile. Two low collisionality H-mode experiments were analyzed, and differences in magnetic field helicity and fast-ion losses were observed. A new analysis technique was developed to investigate the dependencies between fast-ion losses and toroidal rotation, providing correlation patterns resolved in radius and velocity space. The study found that fast-ion transport and losses are influenced by beam geometry and magnetic field helicity, and resonant amplification leads to good agreement with experimental results.
Article
Physics, Fluids & Plasmas
J. McClenaghan, T. Slendebroek, G. M. Staebler, S. P. Smith, O. M. Meneghini, B. A. Grierson, K. E. Thome, G. Avdeeva, L. L. Lao, J. Candy, W. Guttenfelder
Summary: Investigation on linear gyrokinetic ion-scale modes reveals a transition from ion temperature gradient to microtearing mode (MTM) dominance as density increases in the pedestal region of a parameterized DIII-D sized tokamak. Profiles of H-mode densities, temperatures, and equilibria are parameterized to analyze the linear gyrokinetic ion-scale instabilities using CGYRO. The critical n(MTM) scales with plasma current and can be reduced by increasing the minor radius and major radius. However, the relationship between n(MTM) and density limit physics remains unclear.
PHYSICS OF PLASMAS
(2023)
Article
Physics, Fluids & Plasmas
J. Galdon-Quiroga, L. Sanchis-Sanchez, X. Chen, G. Birkenmeier, K. Gage, P. Cano-Megias, J. Gonzalez-Martin, W. W. Heidbrink, O. Putignano, D. Ryan, G. Suarez Lopez, B. Tal, M. A. VanZeeland, E. Viezzer, M. Willensdorfer
Summary: The impact of externally applied magnetic perturbations on fast-ion losses has been studied in ASDEX Upgrade tokamak using the LIBP technique. Different applied MP spectra result in fast-ion orbit displacement, which is independent of the beam source. The minimum displacement occurs at a specific phase difference, which is different from the minimum of the plasma boundary displacement. Simulation results capture the magnitude of orbit displacement and the importance of the toroidal spectrum of the perturbation, while not matching the dependence with the phase difference as observed in experimental measurements.
Article
Physics, Fluids & Plasmas
T. Happel, M. L. Reinke, D. Silvagni, M. Bernert, O. Grover, P. Hennequin, A. E. Hubbard, U. Plank, E. Trier, D. Brida, P. David, R. Fischer, L. Gil, K. Hoefler, P. Manz, R. M. McDermott, A. Merle, U. Stroth, E. Viezzer, M. Willensdorfer
Summary: Experiments on nitrogen assisted divertor detachment in the improved energy confinement mode (I-mode) show that introducing nitrogen leads to cooling of the divertor plasma, resulting in a loss of core confinement and an increase in low frequency edge fluctuation levels. Additional heating power input can compensate for the loss in confinement and maintain the I-mode. Good energy confinement properties are reported during the detachment of the inner divertor leg in these experiments.
Article
Physics, Fluids & Plasmas
Linzi Liu, Ruihai Tong, Xiaolan Zou, Haotian Chen, Yang Chen, Guanqi Dong, Guangzhou Hao, Xiaoxue He, Yuxiao Han, Xiaoquan Ji, Anshu Liang, Bo Li, Jiquan Li, Yonggao Li, Liang Liu, Zhongbin Shi, Huiling Wei, Fan Xia, Guoliang Xiao, Jiao Yin, Deliang Yu, Boda Yuan, Yiren Zhu, Wulyu Zhong, Min Xu
Summary: Instabilities at multiples of the ion cyclotron frequency have been discovered and termed as core ion cyclotron emission (ICE) in recent HL-2A neutral beam injection heated experiments. This study presents the characteristics of core ICE, including frequency dependence and harmonics features. The observed frequencies are found to be consistent with multiples of the deuterium cyclotron frequency near the magnetic axis. In addition, the core ICE exhibits a predominantly compressional property. The study also demonstrates that the core ICE harmonics represent independent multiple modes, with distinct spectrum features and individual excitation of each harmonic. Notably, the 4th harmonic ICE can be individually excited by varying the plasma current, suggesting a variation in the drive mechanism of core ICE across different frequency ranges.
Article
Nuclear Science & Technology
S. Krat, M. Mayer, J. P. Coad, C. P. Lungu, K. Heinola, A. Baron-Wiechec, I Jepu, A. Widdowson
Summary: The study focused on the net erosion of material from recessed areas of the JET main chamber inner wall during the first three ITER-like wall (JET-ILW) campaigns. Both Be and W erosion rates showed changes between campaigns, with potential explanations including testing of power handling capability, changes in incident particle energy distribution, and limiter to divertor discharge time ratio. The net erosion rate of W remained relatively stable through the first two campaigns but increased significantly in the third, possibly due to changes in the energy spectrum of eroding particles and the addition of Kr and Xe to fueling.
NUCLEAR MATERIALS AND ENERGY
(2021)
Article
Physics, Fluids & Plasmas
V. K. Zotta, L. Garzotti, F. J. Casson, D. Frigione, F. Kochl, E. Lerche, P. Lomas, F. Rimini, M. Sertoli, D. Van Eester, R. Gatto, C. Mazzotta, G. Pucella
Summary: The fusion performance of ELMy H-mode 50-50 DT plasmas was predicted using the JINTRAC suite of codes and the QuaLiKiZ transport model. The simulations analyzed the sensitivity of the predictions to plasma parameters and auxiliary heating power, showing that a fusion power of 10 MW should be achievable under a wide range of assumptions, while higher fusion power approaching 15 MW could be achieved with particularly pure plasmas and additional heating power of 40 MW.
Article
Physics, Fluids & Plasmas
G. S. Kurskiev, I. Miroshnikov, N. Sakharov, V. K. Gusev, Yu Petrov, V. B. Minaev, I. M. Balachenkov, N. N. Bakharev, F. Chernyshev, V. Yu Goryainov, A. A. Kavin, N. A. Khromov, E. O. Kiselev, S. Krikunov, K. M. Lobanov, A. D. Melnik, A. N. Novokhatskii, S. Filippov, N. S. Zhiltsov, A. B. Mineev, E. E. Mukhin, M. Patrov, A. Petrov, A. M. Ponomarenko, V. V. Solokha, K. D. Shulyatiev, P. B. Shchegolev, O. M. Skrekel, A. Yu Telnova, E. E. Tkachenko, E. A. Tukhmeneva, V. A. Tokarev, S. Yu Tolstyakov, V. Varfolomeev, A. V. Voronin, A. Yu Yashin, V. A. Solovey, E. G. Zhilin
Summary: Hot ion mode was achieved at the Globus-M2 spherical tokamak by injecting neutral beams and heating the plasma ions to 4 keV, with a high electron density.
Article
Engineering, Mechanical
Syphax Ikardouchene, Stephane Delaby, Xavier Nicolas
Summary: Experiments were conducted to study the interaction between a spray of spherical micronic oil droplets and a turbulent plane air jet impacting a wall. The aim of the study was to separate a contaminated atmosphere with passive particles from a clean atmosphere using a dynamic air curtain. The flow properties were measured using particle image velocimetry and showed good agreement with large eddy simulation results.
EXPERIMENTS IN FLUIDS
(2023)
Article
Physics, Fluids & Plasmas
I. Predebon, D. R. Hatch, L. Frassinetti, L. Horvath, S. Saarelma, B. Chapman-Oplopoiou, T. Goerler, C. F. Maggi
Summary: We compare the isotope mass dependence of the pedestal in two pairs of deuterium/hydrogen type I ELMy H-mode discharges in JET with ITER-like wall. One pair has the same input power, while the other pair has the same stored energy. Using the gyrokinetic code GENE, we focus on the steep profile region of the pedestal. Our findings show that while large wavenumber modes are mainly influenced by the electron heat flux and not by the main gas isotope, there is an ion mass effect in the low wavenumber range consistent with experimental scaling.
Article
Physics, Fluids & Plasmas
B. Lomanowski, G. Rubino, A. Uccello, M. Dunne, N. Vianello, S. Aleiferis, J. Canik, I. Carvalho, G. Corrigan, L. Frassinetti, D. Frigione, L. Garzotti, M. Groth, A. Meigs, M. Maslov, C. Perez von Thun, F. Rimini, P. A. Schneider, G. Sergienko, J. Simpson, D. Van Eester, JET Contributors
Summary: The midplane electron separatrix density, n(e,sep), in JET-ILW L-mode and H-mode low triangularity deuterium fuelled plasmas is strongly influenced by the outer divertor target electron temperature, which is reproduced by an analytic model. The influence of power and momentum loss factors on ne,sep has been quantified using L-mode density ramps in different divertor configurations. The trends and recovery of n(e,sep) are also observed in simulation results using the rev-2PM formatting.
Article
Physics, Fluids & Plasmas
A. Kit, A. E. Jarvinen, L. Frassinetti, S. Wiesen
Summary: The existing models cannot accurately predict the key parameters of tokamak pedestal plasmas. EPED-like models use simplified models to constrain some parameters, but they disagree with experimental observations. In this study, decision tree ensembles and deep learning models are used to improve the predictive quality of pedestal plasmas by incorporating all available tokamak machine control parameters.
PLASMA PHYSICS AND CONTROLLED FUSION
(2023)
Article
Physics, Fluids & Plasmas
I Casiraghi, P. Mantica, R. Ambrosino, L. Aucone, B. Baiocchi, L. Balbinot, T. Barberis, A. Castaldo, M. Cavedon, L. Frassinetti, P. Innocente, F. Koechl, S. Nowak, P. Agostinetti, S. Ceccuzzi, L. Figini, G. Granucci, P. Vincenzi
Summary: Deuterium plasma discharges of the DTT in different scenarios were predicted through a comprehensive first-principle based integrated modelling activity using state-of-art quasi-linear transport models. The focus was on core modelling, while ensuring consistency with scrape-off layer parameters necessary for divertor plasma detachment. The compatibility of these predicted scenarios with the electromagnetic coil system capabilities was verified, and initial estimates of DTT sawteeth and edge localised modes were obtained.
PLASMA PHYSICS AND CONTROLLED FUSION
(2023)
Article
Nuclear Science & Technology
F. Mirizzi, S. Ceccuzzi, B. Baiocchi, A. Cardinali, G. Di Gironimo, G. Granucci, D. Mascali, G. Mauro, D. Milanesio, A. Pidatella, C. Ponti, G. L. Ravera, G. Torrisi, A. A. Tuccillo, G. Vecchi
Summary: This paper presents the preliminary analysis of various typologies of ICRH launchers to determine the most efficient solution for the ICRH system of the Divertor Tokamak Test facility (DTT). Four launchers will be used to couple a nominal power of 6 MW in the frequency range of 60 - 90 MHz to the DTT plasma in its final configuration. This initial analysis was conducted using the ANSYS HFSS code.
FUSION ENGINEERING AND DESIGN
(2023)
Article
Physics, Fluids & Plasmas
S. Saarelma, J. W. Connor, P. Bilkova, P. Bohm, A. R. Field, L. Frassinetti, R. Fridstrom, A. Kirk
Summary: The neutral ionisation model proposed by Groebner et al is extended to include charge exchange processes in the H-mode pedestal, and is tested against JET H-mode pedestal data with good accuracy. The model is able to predict the density pedestal over a wide range of conditions and explain the experimentally observed isotope effect.
Article
Physics, Fluids & Plasmas
J. Horacek, D. Tskhakaya, J. Cavalier, J. Adamek, A. C. Mana, L. Frassinetti, A. Beltrami, S. Lukes, S. Aleiferis, G. Matthews, M. Komm, P. Bilkova, JET Contributors, COMPASS Team
Summary: The analysis of divertor ELM electron temperature at high temporal resolution reveals low peak electron temperatures compared to pedestal ones, which is explained by the transfer of electron energy to ions. However, recent measurements and simulations suggest that the reduction in electron temperature peak in ELM filaments is less than predicted, contradicting previous observations.
Article
Physics, Fluids & Plasmas
Paulo Rodrigues, Duarte Borba, Francesca Cella, Rui Coelho, Jorge Ferreira, Antonio Figueiredo, Mervi Mantsinen, Fernando Nabais, Sergei Sharapov, Paula Siren
Summary: A recent model is used to explain the properties of Alfvenic activity observed on JET plasmas below the frequency of toroidicity-induced Alfven eigenmodes (TAEs). The frequency gaps predicted by the model result from high-order harmonics of the geodesic field-line curvature caused by plasma shaping and give rise to high-order geodesic acoustic eigenmodes (HOGAEs), their frequency value being close to one-half of the TAEs one. The theoretical predictions of HOGAE frequency and radial location are in fair agreement with measurements in JET experiments.
Article
Physics, Fluids & Plasmas
L. Horvath, B. Lomanowski, J. Karhunen, M. Maslov, P. A. Schneider, J. Simpson, M. Brix, B. Chapman-Oplopoiou, G. Corrigan, L. Frassinetti, M. Groth, K. Lawson, C. F. Maggi, S. Menmuir, R. B. Morales, D. Moulton, O. Myatra, D. Nina, T. Pereira, D. Refy, S. Saarelma, M. Vecsei
Summary: In this experiment, JET-ILW type I ELMy H-modes were studied with constant NBI heating and gas fuelling rate. The effects of ELMs, inter-ELM transport, and edge stability on the pedestal particle balance were investigated using ELM pacing and plasma shaping techniques. The results showed that increasing triangularity improved the pedestal confinement by increasing the pedestal density and decreasing the ELM frequency. The analysis also revealed the importance of transport in the inter-ELM pedestal recovery.
PLASMA PHYSICS AND CONTROLLED FUSION
(2023)
Article
Nuclear Science & Technology
F. Fanale, B. Baiocchi, A. Bruschi, D. Busi, A. Bussolan, L. Figini, S. Garavaglia, G. Granucci, A. Romano
Summary: One of the main goals of the Divertor Tokamak Test (DTT) facility is to achieve a specific ratio of power crossing the separatrix over the major radius, similar to what is expected in DEMO. In order to reach this goal, various external heating methods, including Electron Cyclotron Resonance Heating (ECRH), are being used. This paper focuses on the design of the antennas and the matching optics unit for the ECRH system, as well as the modifications required for the in-vessel optics and supporting structure.
FUSION ENGINEERING AND DESIGN
(2023)
Article
Physics, Fluids & Plasmas
M. Fitzgerald, R. Dumont, D. Keeling, J. Mailloux, S. Sharapov, M. Dreval, A. Figueiredo, R. Coelho, J. Ferreira, P. Rodrigues, F. Nabais, D. Borba, Z. Stancar, G. Szepesi, R. A. Tinguely, P. G. Puglia, H. J. C. Oliver, V. Kiptily, M. Baruzzo, M. Lennholm, P. Siren, J. Garcia, C. F. Maggi
Summary: A toroidal Alfvén eigenmode (TAE) driven by alpha particles in a JET plasma was observed, whose mode was found to be weak due to non-ideal effects from the bulk plasma.
Article
Physics, Fluids & Plasmas
L. Frassinetti, C. Perez Von Thun, B. Chapman-Oplopoiou, H. Nystrom, M. Poradzinski, J. C. Hillesheim, L. Horvath, C. F. Maggi, S. Saarelma, A. Stagni, G. Szepesi, A. Bleasdale, A. Chomiczewska, R. B. Morales, M. Brix, P. Carvalho, D. Dunai, A. R. Field, J. M. Fontdecaba, H. J. Sun, D. B. King, D. Kos, E. Kowalska, B. Labit, M. Lennholm, S. Menmuir, E. Rachlew, D. I. Refy, P. A. Schneider, E. R. Solano, N. Vianello, M. Vecsei, JET Contributors
Summary: The study investigates the structure, transport, and stability of the pedestal from pure deuterium to pure tritium plasmas. Experimental and modeling results suggest a reduction in inter-edge localized mode transport and an improvement in pedestal stability from deuterium to tritium.
Article
Physics, Fluids & Plasmas
H. J. C. Oliver, S. E. Sharapov, Z. Stancar, M. Fitzgerald, E. Tholerus, B. N. Breizman, M. Dreval, J. Ferreira, A. Figueiredo, J. Garcia, N. Hawkes, D. L. Keeling, P. G. Puglia, P. Rodrigues, R. A. Tinguely
Summary: The Joint European Torus conducted an experimental campaign using a mixture of deuterium (D) and tritium (T) plasma and observed a high-frequency mode known as the toroidal Alfven eigenmode (TAE). Through simulations and calculations, it was found that the TAE can be driven by beam ions with high toroidal mode numbers, while alpha particles contribute less to the driving force. Radiative damping was identified as the dominant damping mechanism. The observed TAE matched the calculated results.
Proceedings Paper
Nuclear Science & Technology
Benedetta Baiocchi, Lorenzo Figini, Alessandro Bruschi, Francesco Fanale, Saul Garavaglia, Gustavo Granucci, Afra Romano
Summary: In this study, the Electron Cyclotron (EC) physics performances of the EC system planned for the new Divertor Tokamak Test facility (DTT) during the flat top phase were investigated using the beam tracing code GRAY. The results showed that the EC beams can effectively heat the core plasma region and drive core current, as well as mitigate the NTM on rational surfaces. The influence of density fluctuations caused by pellet injection on the EC propagation, absorption, and current drive location was analyzed, and it was found that the pellet injection has negligible effects on the EC performances. Additionally, the polarization variations due to angle steering during the discharge were assessed, and it was concluded that negligible power losses occur when maintaining fixed polarization.
21ST JOINT WORKSHOP ON ELECTRON CYCLOTRON EMISSION AND ELECTRON CYCLOTRON RESONANCE HEATING, EC21
(2023)
