Publications (71)
Variational Formulation of a Hybrid Kinetic and Gyrokinetic Model for Astrophysical and Laboratory Plasmas
F. N. deOliveira-Lopes, S. C. Thatikonda, D. Told +5
The paper introduces a Lagrangian model that couples fully kinetic ions with gyrokinetic electrons to efficiently simulate solar‑wind electromagnetic turbulence, using variational…
Free energy cascade in gyrokinetic turbulence
A. Bañón Navarro, P. Morel, M. Albrecht-Marc +4
In gyrokinetic theory, the quadratic nonlinearity is known to play an important role in the dynamics by redistributing (in a conservative fashion) the free energy between the vario…
Gyrokinetic studies of core turbulence features in ASDEX Upgrade H-mode plasmas
A. Banon Navarro, T. Happel, T. Goerler +6
Gyrokinetic validation studies are crucial in developing confidence in the model incorporated in numerical simulations and thus improving their predictive capabilities. As one step…
New high-confinement regime with fast ions in the core of fusion plasmas
A. Di Siena, R. Bilato, T. Görler +12
The key result of the present work is the theoretical prediction and observation of the formation of a new type of transport barrier in fusion plasmas, called F-ATB (fast ion-induc…
First global gyrokinetic profile predictions of ITER burning plasma
A. Di Siena, C. Bourdelle, A. Bañón Navarro +11
In this work, we present the first global gyrokinetic simulations of the ITER baseline scenario operating at 15 MA using GENE-Tango electrostatic and electromagnetic simulations. T…
Improved energy confinement with nonlinear isotope effects in magnetically confined plasmas
J. Garcia, T. Goerler, F. Jenko
The efficient production of electricity from nuclear fusion in magnetically confined plasmas relies on a good confinement of the thermal energy. For more than thirty years, the obs…
Gyrokinetic investigation of Alfvén instabilities in the presence of turbulence
A. Biancalani, A. Bottino, A. Di Siena +5
The global and electromagnetic gyrokinetic particle-in-cell code ORB5 is employed to investigate the self-consistent interactions between Alfvén modes (AM) and ion temperature gra…
Classification of tokamak plasma confinement states with convolutional recurrent neural networks
F. Matos, V. Menkovski, F. Felici +2
During a tokamak discharge, the plasma can vary between different confinement regimes: Low (L), High (H) and, in some cases, a temporary (intermediate state), called Dithering (D).…
Continuous Time Random Walks with Internal Dynamics and Subdiffusive Reaction-Diffusion Equations
S. Eule, R. Friedrich, F. Jenko +1
We formulate the generalized master equation for a class of continuous time random walks in the presence of a prescribed deterministic evolution between successive transitions. Thi…
First-Principles Explanation of the Drift Configuration Dependence of the Radial Electric Field and High-Confinement Access in Tokamaks
B. J. Frei, R. Bilato, O. Grover +6
The origin of the difference in the high-confinement (H-mode) power threshold between favorable and unfavorable drift configurations in tokamaks, experimentally linked to a deeper…
Wave-driven dynamo action in spherical MHD systems
K. Reuter, F. Jenko, A. Tilgner +1
Hydrodynamic and magnetohydrodynamic numerical studies of a mechanically forced two-vortex flow inside a sphere are reported. The simulations are performed in the intermediate regi…
Verification of a hybrid gyrokinetic model using the advanced semi-Lagrange code ssV
Sreenivasa chary Thatikonda, F. N. De Oliveira-Lopes, A. Mustonen +3
The super simple Vlasov (ssV) code was developed to study instabilities, turbulence, and reconnection in weakly magnetized plasmas, such as the solar wind in the dissipation range…
Magnetic reconnection as a driver for a sub-ion scale cascade in plasma turbulence
L. Franci, S. S. Cerri, F. Califano +6
A new path for the generation of a sub-ion scale cascade in collisionless plasma turbulence, triggered by magnetic reconnection, is uncovered by means of high-resolution two-dimens…
Nonlocal effects in negative triangularity TCV plasmas
G. Merlo, Z. Huang, C. Marini +7
Global gradient driven GENE gyrokinetic simulations are used to investigate TCV plasmas with negative triangularity. Considering a limited L-mode plasma, corresponding to an experi…
Pressure tensor in the presence of velocity shear: stationary solutions and self-consistent equilibria
S. S. Cerri, F. Pegoraro, F. Califano +2
Observations and numerical simulations of laboratory and space plasmas in almost collisionless regimes reveal anisotropic and non-gyrotropic particle distribution functions. We inv…
Spectrally Accelerated Edge and Scrape-Off Layer Gyrokinetic Turbulence Simulations
B. J. Frei, P. Ulbl, J. Trilaksono +1
This paper presents the first gyrokinetic (GK) simulations of edge and scrape-off layer (SOL) turbulence accelerated by a velocity-space spectral approach in the full-f GK code GEN…
Gyrokinetic investigation of Alfvén instabilities in the presence of turbulence
A. Biancalani, A. Bottino, A. Di Siena +10
The nonlinear dynamics of beta-induced Alfvén Eigenmodes (BAE) driven by energetic particles (EP) in the presence of ion-temperature-gradient (ITG) turbulence is investigated, by…
Hybrid simulation of a parallel collisionless shock in the Large Plasma Device
M. S. Weidl, D. Winske, F. Jenko +1
We present two-dimensional hybrid kinetic/magnetohydrodynamic simulations of planned laser-ablation experiments in the Large Plasma Device (LAPD). Our results, based on parameters…
Ion temperature profile stiffness: non-linear gyrokinetic simulations and comparison with experiment
J. Citrin, F. Jenko, P. Mantica +9
Recent experimental observations at JET show evidence of reduced ion temperature profile stiffness, hypothesised to be due to concomitant low magnetic shear (s) and significant tor…
Fast transport simulations with higher-fidelity surrogate models for ITER
J. Citrin, P. Trochim, T. Goerler +3
A fast and accurate turbulence transport model based on quasilinear gyrokinetics is developed. The model consists of a set of neural networks trained on a bespoke quasilinear GENE…
Fully Kinetic Simulation of 3D Kinetic Alfven Turbulence
D. Groselj, A. Mallet, N. F. Loureiro +1
We present results from a three-dimensional particle-in-cell simulation of plasma turbulence, resembling the plasma conditions found at kinetic scales of the solar wind. The spectr…
Gyrokinetic Large Eddy Simulations
P. Morel, A. Bañón Navarro, M. Albrecht-Marc +4
The Large Eddy Simulation (LES) approach is adapted to the study of plasma microturbulence in a fully three-dimensional gyrokinetic system. Ion temperature gradient driven turbulen…
Plasmoid formation via competing lower-hybrid drift and Kelvin-Helmholtz instabilities: A hybrid kinetic-gyrokinetic simulation study
S. Thatikonda, F. N. De Oliveira-Lopes, A. Mustonen +3
We investigate the nonlinear formation of plasmoids in 2D low-beta current sheets through the interplay between the Kelvin-Helmholtz instability (KHI) and the lower-hybrid drift in…
Comparison between measured and predicted turbulence frequency spectra in ITG and TEM regimes
J. Citrin, H. Arnichand, J. Bernardo +6
The observation of distinct peaks in tokamak core reflectometry measurements - named quasi-coherent-modes (QCMs) - are identified as a signature of Trapped-Electron-Mode (TEM) turb…
Subproton-scale cascades in solar wind turbulence: driven hybrid-kinetic simulations
S. S. Cerri, F. Califano, F. Jenko +2
A long-lasting debate in space plasma physics concerns the nature of subproton-scale fluctuations in solar wind (SW) turbulence. Over the past decade, a series of theoretical and o…
Global gyrokinetic simulations of ASDEX Upgrade up to the transport time-scale with GENE-Tango
A. Di Siena, A. Banon Navarro, T. Luda +12
An accurate description of turbulence up to the transport time scale is essential for predicting core plasma profiles and enabling reliable calculations for designing advanced scen…
Gyrokinetic GENE simulations of DIII-D near-edge L-mode plasmas
T. F. Neiser, F. Jenko, T. A. Carter +7
We present gyrokinetic simulations with the GENE code addressing the near-edge region of an L-mode plasma in the DIII-D tokamak. At radial position , simulations with the…
Langevin Approach to Fractional Diffusion Equations including Inertial Effects
R. Friedrich, S. Eule, F. Jenko
In recent years, several fractional generalizations of the usual Kramers-Fokker-Planck equation have been presented. Using an idea of Fogedby [H.C. Fogedby, Phys. Rev. E {\bf 50},…
Radiative signatures of electron-ion shocks in BL Lac type objects
A. Arbet-Engels, A. Bohdan, F. Rieger +2
Shocks are promising sites of particle acceleration in extragalactic jets. In electron-ion shocks, electrons can be heated up to large Lorentz factors, making them an attractive sc…
Turbulence and Transport in Spectrally Accelerated full-f Gyrokinetic Simulations
B. J. Frei, P. Ulbl, C. Pitzal +2
We investigate edge and scrape-off layer (SOL) turbulence and transport using the spectrally accelerated full-f gyrokinetic (GK) code GENE-X, recently introduced in [B. J. Frei et…
Electron-only reconnection and ion heating in 3D3V hybrid-Vlasov plasma turbulence
C. Granier, S. S. Cerri, F. Jenko
We perform 3D3V hybrid-Vlasov simulations of turbulence with quasi-isotropic, compressible injection near ion scales to mimic the Earth's magnetosheath plasma, and investigate the…
Predictions of improved confinement in SPARC via energetic particle turbulence stabilization
A. Di Siena, P. Rodriguez-Fernandez, N. T. Howard +8
The recent progress in high-temperature superconductor technologies has led to the design and construction of SPARC, a compact tokamak device expected to reach plasma breakeven wit…
Multiscale turbulence in stellarators
G. Merlo, A. Bañón Navarro, T. Görler +2
We present the first gyrokinetic simulations of multiscale turbulence in a stellarator, using the magnetic geometry of Wendelstein 7-X (W7-X) and experimentally relevant parameters…
Assessing global ion thermal confinement in critical-gradient-optimized stellarators
A. Bañón Navarro, G. T. Roberg-Clark, G. G. Plunk +4
We investigate the confinement properties of two recently devised quasi-helically symmetric stellarator configurations, HSK and QSTK. Both have been optimized for large critical gr…
Kinetic Turbulence in Astrophysical Plasmas: Waves and/or Structures?
D. Groselj, C. H. K. Chen, A. Mallet +3
The question of the relative importance of coherent structures and waves has for a long time attracted a great deal of interest in astrophysical plasma turbulence research, with a…
Instabilities and turbulence in stellarators from the perspective of global codes
E. Sánchez, A. Bañón Navarro, F. Wilms +3
In this work, a comparison of the global gyrokinetic codes EUTERPE and GENE-3D in stellarator configurations of LHD and W7-X is carried out. In linear simulations with adiabatic el…
Global gyrokinetic simulations of ITG turbulence in the configuration space of the Wendelstein 7-X stellarator
A. Bañón Navarro, G. Merlo, G. G. Plunk +7
We study the effect of turbulent transport in different magnetic configurations of the Weldenstein 7-X stellarator. In particular, we performed direct numerical simulations with th…
The Structure of Plasma Heating in Gyrokinetic Alfvénic Turbulence
A. B. Navarro, B. Teaca, D. Told +3
We analyze plasma heating in weakly collisional kinetic Alfvén wave (KAW) turbulence using high resolution gyrokinetic simulations spanning the range of scales between the ion and…
Lagrangian Particle Statistics in Turbulent Flows from a Simple Vortex Model
M. Wilczek, F. Jenko, R. Friedrich
The statistics of Lagrangian particles in turbulent flows is considered in the framework of a simple vortex model. Here, the turbulent velocity field is represented by a temporal s…
Anomalous Diffusion of Inertial, Weakly Damped Particles
R. Friedrich, F. Jenko, A. Baule +1
The anomalous (i.e. non-Gaussian) dynamics of particles subject to a deterministic acceleration and a series of 'random kicks' is studied. Based on an extension of the concept of c…
Pre L-H Transition Radial Electric Field and Transport Validations of Edge and Scrape-off Layer Gyrokinetic Simulations at ASDEX Upgrade
B. J. Frei, C. Angioni, G. Lo-Cascio +5
This work presents a stepwise validation of the evolution of the radial electric field (Er) and heat transport during the pre L-H transition phase using full-f gyrokinetic simulati…
Study of the impact of fast ions on core turbulence at rational surfaces via global gyrokinetic simulations
D. Brioschi, A. Di Siena, R. Bilato +6
In this work, the interplay between fast ions and safety factor rational surfaces is studied in a turbulent plasma via global nonlinear gyrokinetic simulations. Initially, the fast…
How accurate are flux-tube (local) gyrokinetic codes in modeling energetic particle effects on core turbulence?
A. Di Siena, T. Hayward-Schneider, P. Mantica +8
Flux-tube gyrokinetic codes are widely used to simulate drift-wave turbulence in magnetic confinement devices. While a large number of studies show that flux-tube codes provide an…
Assessing the Impact of Alpha Particles on Thermal Confinement in JET D-T Plasmas through Global GENE-Tango Simulations
A. Di Siena, J. Garcia, R. Bilato +14
The capability of the global, electromagnetic gyrokinetic GENE code interfaced with the transport Tango solver is exploited to address the impact of fusion alpha particles (in thei…
Investigating the Lower Hybrid Drift Instability in Reconnecting Current Sheets Using a Hybrid Kinetic Model (ssV Code)
S. Thatikonda, F. N. De Oliveira-Lopes, A. Mustonen +3
We investigate the nonlinear evolution of the lower hybrid drift instability (LHDI) in reconnecting current sheets using a hybrid kinetic simulation model implemented in the Super…
Validation of edge turbulence codes against the TCV-X21 diverted L-mode reference case
D. S. Oliveira, T. Body, D. Galassi +27
Self-consistent full-size turbulent-transport simulations of the divertor and SOL of existing tokamaks have recently become feasible. This enables the direct comparison of turbulen…
Simulating X-point radiator turbulence
K. Eder, W. Zholobenko, A. Stegmeir +5
Coupling a high-performance burning plasma core to a detached boundary solution is critical for realizing magnetic confinement fusion power. Predictive simulations of the edge and…
Microtearing Turbulence and Its Role in High-Density-Gradient Plasmas in Wendelstein 7-X
H. Cu-Castillo, A. Bañón Navarro, G. Merlo +10
Gyrokinetic simulations reveal that microtearing mode (MTM) turbulence dominates transport in a Wendelstein 7-X (W7-X) discharge characterized by large density gradients, moderate…
Understanding nonlinear saturation in zonal-flow-dominated ion temperature gradient turbulence
G. G. Plunk, A. Bañón Navarro, F. Jenko
We propose a quantitative model of ion temperature gradient driven turbulence in toroidal magnetized plasmas. In this model, the turbulence is regulated by zonal flows, i.e. mode s…
Direct multiscale coupling of a transport code to gyrokinetic turbulence codes
M. Barnes, I. G. Abel, W. Dorland +3
Direct coupling between a transport solver and local, nonlinear gyrokinetic calculations using the multiscale gyrokinetic code TRINITY [M. Barnes, Ph.D. thesis, arxiv:0901.2868] is…
Electromagnetic stabilization of tokamak microturbulence in a high- regime
J. Citrin, J. Garcia, T. Goerler +9
The impact of electromagnetic stabilization and flow shear stabilization on ITG turbulence is investigated. Analysis of a low- JET L-mode discharge illustrates the relation bet…
Complex structure of turbulence across the ASDEX Upgrade pedestal
L. A. Leppin, T. Görler, M. Cavedon +4
The theoretical investigation of relevant turbulent transport mechanisms in H-mode pedestals is a great scientific and numerical challenge. In this study, we address this challenge…
Microtearing modes as the source of magnetic fluctuations in the JET pedestal
D. R. Hatch, M. Kotschenreuther, S. M. Mahajan +15
We report on a detailed study of magnetic fluctuations in the JET pedestal, employing basic theoretical considerations, gyrokinetic simulations, and experimental fluctuation data,…
Towards optimal explicit time-stepping schemes for the gyrokinetic equations
H. Doerk, F. Jenko
The nonlinear gyrokinetic equations describe plasma turbulence in laboratory and astrophysical plasmas. To solve these equations, massively parallel codes have been developed and r…
Validation of a Comprehensive First-Principles-Based Framework for Predicting the Performance of Future Stellarators
D. L. C. Agapito Fernando, A. Bañón Navarro, D. Carralero +20
This paper presents the validation of the framework for recovering both the steady-state plasma profiles in the considered radial domain and selected t…
Electromagnetic turbulence suppression by energetic particle driven modes
A. Di Siena, T. Görler, E. Poli +3
In recent years, a strong reduction of plasma turbulence in the presence of energetic particles has been reported in a number of magnetic confinement experiments and corresponding…
Multiscale nature of the dissipation range in gyrokinetic simulations of Alfvénic turbulence
D. Told, F. Jenko, J. M. TenBarge +2
Nonlinear energy transfer and dissipation in Alfvén wave turbulence are analyzed in the first gyrokinetic simulation spanning all scales from the tail of the MHD range to the elec…
Anomalous Diffusion of particles with inertia in external potentials
S. Eule, R. Friedrich, F. Jenko
Recently a new type of Kramers-Fokker-Planck Equation has been proposed [R. Friedrich et al. Phys. Rev. Lett. {\bf 96}, 230601 (2006)] describing anomalous diffusion in external po…
Global turbulence simulations of the tokamak edge region with GRILLIX
A. Stegmeir, A. Ross, T. Body +8
Turbulent dynamics in the scrape-off layer (SOL) of magnetic fusion devices is intermittent with large fluctuations in density and pressure. Therefore, a model is required that all…
Nonlinear stabilization of tokamak microturbulence by fast ions
J. Citrin, C. Bourdelle, J. Garcia +8
Nonlinear electromagnetic stabilization by suprathermal pressure gradients found in specific regimes is shown to be a key factor in reducing tokamak microturbulence, augmenting sig…
Simulations of edge and SOL turbulence in diverted negative and positive triangularity plasmas
P. Ulbl, A. Stegmeir, D. Told +3
Optimizing the performance of magnetic confinement fusion devices is critical to achieving an attractive fusion reactor design. Negative triangularity (NT) scenarios have been show…
Self-consistent modeling of runaway electron generation in massive gas injection scenarios in ASDEX Upgrade
O. Linder, E. Fable, F. Jenko +4
We present the first successful simulation of a induced disruption in ASDEX Upgrade from massive material injection (MMI) up to established runaway electron (RE) beam, thus coverin…
Applications of Large Eddy Simulation methods to gyrokinetic turbulence
A. Bañón Navarro, B. Teaca, F. Jenko +3
The Large Eddy Simulation (LES) approach - solving numerically the large scales of a turbulent system and accounting for the small-scale influence through a model - is applied to n…
Collision-dependent power law scalings in 2D gyrokinetic turbulence
S. S. Cerri, A. Bañón Navarro, F. Jenko +1
Nonlinear gyrokinetics provides a suitable framework to describe short-wavelength turbulence in magnetized laboratory and astrophysical plasmas. In the electrostatic limit, this sy…
Electron runaway in ASDEX Upgrade experiments of varying core temperature
O. Linder, G. Papp, E. Fable +4
The formation of a substantial post-disruption runaway electron current in ASDEX Upgrade material injection experiments is determined by avalanche multiplication of a small seed po…
Fully kinetic versus reduced-kinetic modelling of collisionless plasma turbulence
D. Groselj, S. S. Cerri, A. Banon Navarro +5
We report the results of a direct comparison between different kinetic models of collisionless plasma turbulence in two spatial dimensions. The models considered include a first pr…
The JET hybrid H-mode scenario from a pedestal turbulence perspective
L. A. Leppin, T. Görler, L. Frassinetti +4
Turbulent transport is a decisive factor in determining the pedestal structure of H-modes. Here, we present the first comprehensive characterization of gyrokinetic turbulent transp…
Optimizing Particle Transport for Enhanced Confinement in Quasi-Isodynamic Stellarators
A. Bañón Navarro, A. Di Siena, F. Jenko +2
Despite significant advances in reducing turbulent heat losses, modern quasi-isodynamic (QI) stellarators -- such as Stellaris -- continue to suffer from poor particle confinement,…
Core transport barriers induced by fast ions in global gyrokinetic GENE simulations
A. Di Siena, R. Bilato, T. Goerler +4
A novel type of internal transport barrier (ITB) called F-ATB (fast ion-induced anomalous transport barrier) has been recently observed in state-of-the-art global gyrokinetic simul…
First-principles based plasma profile predictions for optimized stellarators
A. Bañón Navarro, A. Di Siena, J. L. Velasco +6
In the present Letter, first-of-its-kind computer simulations predicting plasma profiles for modern optimized stellarators -- while self-consistently retaining neoclassical transpo…
Gyrokinetic and kinetic particle-in-cell simulations of guide-field reconnection. I: Macroscopic effects of the electron flows
P. A. Muñoz, D. Told, P. Kilian +2
In this work, we compare gyrokinetic (GK) and fully kinetic Particle-in-Cell (PIC) simulations of magnetic reconnection in the limit of strong guide field. In particular, we analyz…