Varenna–Lausanne 2026

Workshop archive: agenda, speakers, committee, and group photo

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Group Photo

2026 Varenna–Lausanne group photo

2026 Varenna–Lausanne group photo

Agenda and Proceedings

The full programme and proceedings material for the 2026 workshop are available below.

PPCF submission deadline: April 30th, 2027.

How to submit: Invited speakers submit directly to PPCF. Poster presenters were asked to send an early draft to varenna-lausanne@epfl.ch by 14 September 2026 for workshop refereeing; drafts not prepared in time could still be sent to the editors after the workshop and considered for the issue.

Please use the PPCF author guidelines and templates, and when submitting, select the special issue titled: "Special issue on the 2026 joint Varenna–Lausanne International Workshop on the Theory of Fusion Plasmas."

Agenda

Full programme for the Joint Varenna–Lausanne International Workshop on the Theory of Fusion Plasmas at Villa Monastero, Varenna, Italy, 21–25 September 2026.

Sunday, 20 September 2026

16:00 – 19:00 Registration in Villa Monastero

Monday, 21 September 2026

9:00 Welcome — J. Graves and P. Helander

Session 1: Fundamental Theory of Turbulence and Transport

9:10 I-1
A. Schekochihin
Tutorial: "As simple as possible but not simpler": physics of turbulence and transport in fusion plasmas via reduced fluid models
9:55 I-2
G. Acton
Computational and Theoretical Advances for Zonal Flows in Stellarators
10:40 Coffee break
11:10 I-3
K. Zhang
Exploring Tokamak Boundary Turbulence with GRILLIX Simulations: From L-Mode to H-Mode and the Quasi-Continuous Exhaust Regime
11:55 I-4
P. Costello
Constrained optimal modes: tightening thermodynamic bounds on the linear growth rate of microinstabilities
12:40 Group photo in Villa Monastero's garden
12:50 Lunch

Session 2: Tokamak Plasma Regimes

15:00 I-5
N. Rivals
Understanding of the X-Point Radiator regimes in tokamaks through an example in the WEST device
15:45 I-6
F. Maiden
The theory behind solenoid-free microwave driven start-up in tokamaks
16:30 Coffee break
17:00 I-7
J. Burby
Statistical equilibrium model for stellarators
17:45 End
19:30 Welcome Party — Blanco Lounge Bar, Varenna

Tuesday, 22 September 2026

Session 3: Fast Ions, Runaways and Heat Transport in Stellarators

9:00 I-8
T. Foster
Analytical formulas for alpha-particle orbits in stellarators
9:45 I-9
M. Fitzgerald
Conservation and destruction of alpha particle invariants in optimized stellarators
10:30 Coffee break
11:00 I-10
I. Ekmark
Runaway electrons in stellarators: Unlikely or unavoidable
11:45 I-11
H. Thienpondt
Nonlinear critical gradients in W7-X: Insights from massive gyrokinetic simulations and experimental measurements of turbulent heat transport
12:30 Lunch

14:30 – 16:00   Poster session 1: P1 – P13

16:00 – 16:30   Coffee break

16:30 – 18:00   Poster session 2: P14 – P26

Wednesday, 23 September 2026

Session 4: Microturbulent Transport and Gyrokinetics in Tokamaks

9:00 I-12
H. Sun
The unusual dynamics of turbulent transport in spherical tokamaks with large field line pitch angle
9:45 I-13
L. De Gianni
Understanding Trapped Electron Modes in negative triangularity
10:30 I-14
S. Liu
Development of the Gyrokinetic-MHD Hybrid Code cuGMEC and Its Nonlinear Simulations of Alpha Particle-driven Alfvén Eigenmodes in ITER
11:15 Coffee break
11:35 I-15
S. Choudhary
Gyrokinetic Transport in flat-Temperature Tokamak Plasmas
12:20 I-16
J. McClenaghan
Integrating Gyrokinetic Flux Predictions with Ideal MHD Stability Boundaries
13:05 Lunch
19:30 Conference dinner — Ristorante La Breva, Lierna (dinner at 20:00, bus at 19:30)

Thursday, 24 September 2026

Session 5: Stellarator Optimisation

9:00 I-17
J. Velasco
Tutorial: New avenues for stellarator design enabled by piecewise omnigenity
9:45 I-18
W. Sengupta
Periodic Korteweg-de Vries soliton potentials generate quasisymmetric magnetic field strength in both vacuum and finite plasma-beta equilibrium
10:30 Coffee break
11:00 I-19
A. Goodman
Searching for SQuIDs: Developments in the optimisation of Stable Quasi-Isodynamic Designs
11:45 I-20
P. Jurašić
Designing stellarator island divertors by controlling the island flux
12:30 Lunch

14:30 – 16:00   Poster session 3: P27 – P39

16:00 – 16:30   Coffee break

16:30 – 18:00   Poster session 4: P40 – P51

Friday, 25 September 2026

Session 6: Fast Ion and Nonlinear Physics in Tokamaks

9:00 I-21
H. Cai
Cross-scale Interaction between Microturbulence and Fishbone in Fusion Plasmas
9:45 I-22
D. Korger
A nonlinear Schrödinger equation for the description of geodesic-acoustic-modes in tokamaks
10:30 Coffee break
11:00 I-23
J. Wang
Comprehensive simulations of bursting shear Alfvén waves in tokamaks and their control via phase space engineering with ICRF waves
11:45 I-24
E. G. Devin
Nonlinear evolution of strongly driven perturbative kinetic instabilities
12:30 Closing session
12:45 End

Poster List

P1: Kinetic ballooning modes and electromagnetic stability in W7-X — K. Aleynikova

P2: Gyrokinetic investigation of zero magnetic shear regions in tokamaks — O. Anuaruly

P3: Simplest Models of Tokamak MHD — Wayne Arter

P4: Gyrokinetic analysis of internal transport barriers in stellarators — J. Ball

P5: Reduced model of the interaction between microturbulence, energetic particles and energetic particle driven modes — T. Barberis

P6: MHD Equilibria via Voigt Regularization — Andrew Brown

P7: Analysis of the electromagnetic and electrostatic instability induced by runaway electrons in a magnetized plasma — A. Cardinali

P8: Nonlinear saturation of Axisymmetric (n=0) modes driven by Energetic Particles in Tokamaks — S. Cavallero

P9: Stellarator design points and optimized equilibria for compact high-field nuclear fusion reactors — F. Ceccherini

P10: Application of ECRH and NBI in compact high-field stellarator nuclear fusion reactors — L. Galeotti

P11: Minimal Model for Floquet Modes in a Tokamak — M. Evans

P12: Validation and benchmarking of gyrokinetics in low-recycling lithiated conditions with Gkeyll and XGC — M. Francisquez

P13: Effect of magnetic drift on the stability structure of the ambipolar condition in nonaxisymmetric plasmas — K. Fujita

P14: Resonant staircase formation and zonal flow amplification in tokamak turbulence: the role of negative mass instability and mode synchronization — D. Del Sarto

P15: Analytical approximation of the velocity distribution through the collisional layer — A. Geraldini

P16: Continuous linear to nonlinear analytic treatment of tearing and double tearing modes with toroidal effects and fast particles — J. P. Graves

P17: Bootstrap current beyond the near omnigenous asymptotic model — G. Graßler

P18: Runaway-Electron Avalanches as a Branching Markov Process — S. Guinchard

P19: Driftless Star: an end-to-end pipeline for transport-consistent stellarator optimization — R. K. Hashmani

P20: Dynamics of ion temperature gradient modes in burning plasma conditions in the presence of energetic particles — R. Ivanov

P21: kobra: a new Vlasov code with AMR — S. Konewko

P22: Full-F Gyrofluid Vortex interaction with arbitrary wavelength Polarization — Franz. F. Locker

P23: Second stability region for gyrokinetics and the L-H transition — R.J.J. Mackenbach

P24: Global Fluid Turbulence Simulations of W7-X Internal Magnetic Island Configurations — M. Madeira

P25: Reduced Magnetohydrodinamics studies on tungsten transport inside magnetic islands — Chiara Marchetto

P26: Interpretation of the Dimits shift as a phase transition — L. N. Marquant

P27: Kinetic modeling of emissive plasma sheath — A. Medouni

P28: Fast ITG eigenmode-eigenfrequency prediction in general geometry — M.C.L. Morren

P29: An improved knock-on operator for runaway avalanche modelling — Isabel Muzio

P30: Direct optimization of steady-state plasma profiles in stellarators — E. Lascas Neto

P31: Theory of nonlinear zonal flow dynamics in toroidal geometry — R. Nies

P32: On the Shafranov shift in stellarators — P. Helander

P33: The role of different nonlinearities in two-dimensional fluid ITG models — G. Paramasivam

P34: Gradient-driven instabilities in 2D models for tokamak edge — F.I. Parra

P35: Stellarator-Tokamak Hybrid configurations for representative TCV discharges — L. Rais

P36: Convective-diffusive modeling of anomalous particle and energy transport in 2D interchange-dominated simulations. — O. Renders

P37: Nonlinear interactions between energetic particles, Alfvén eigenmodes and ITG driven turbulence in global, gyrokinetic, electromagnetic simulations — B. Rofman

P38: Assessing the effect of alpha-particle-driven modes on the fusion power gain in a burning plasma — J. Ruiz Ruiz

P39: Understanding the sensitivities of the radial electric field between favorable and unfavorable configurations using SOLEDGE3X simulations — G. El Saifi

P40: Plasma transport in a chaotic magnetic field using an MHD model — V. Simon

P41: Nonlocal integral kernels for ICRH – Progress with the implementation into PSYDAC — C. Slaby

P42: Guiding center motion in self-consistent axisymmetric mirror equilibria — C. D. Stephens

P43: Adjoint-based trust region method with DGSEM discretization for MRxMHD in HKT slab geometry — Rongping Tang

P44: Solving the phase-space relaxed MHD model: from cross-field flow to the weak ideal Ohm's law — A. Tavassoli

P45: Stellarator Coil Optimization for Beta-Resilient Divertor Island Positioning — M. Titze

P46: Electron-temperature-gradient turbulence and secondary-instability saturation with large density gradients — L.-P. Turica

P47: Kinetic solutions to the stationary collisionless magnetised plasma sheath — Nicole Vadot

P48: 3D JOREK simulations of runaway electron benign termination on TCV — C. Wang

P49: Impacts of effective diffusion caused by electron temperature gradient turbulence — Tomo-Hiko Watanabe

P50: Nonlinear frequency chirping of energetic-particle-driven geodesic acoustic modes — R. Wu

P51: On the kinetic continuous spectrum in toroidal plasmas — F. Zonca

Invited Speakers 2026

The following speakers have been invited to present at the 2026 Varenna-Lausanne Workshop, September 21–25, Varenna, Italy.

Acton, Georgia
IPP Greifswald, Germany
Computational and Theoretical Advances for Zonal Flows in Stellarators
Korger, David
IPP Garching, Germany
A nonlinear Schrödinger equation for the description of geodesic-acoustic-modes in tokamaks
Burby, Joshua
Austin University, Texas, USA
Statistical equilibrium model for stellarators
Liu, Shiyang
Zhejiang University, Hangzhou, China
Development of the Gyrokinetic-MHD Hybrid Code cuGMEC and Its Nonlinear Simulations of Alpha Particle-driven Alfvén Eigenmodes in ITER
Cai, Huishan
USTC, Hefei, China
Cross-scale Interaction between Microturbulence and Fishbone in Fusion Plasmas
Maiden, Felicity
UKAEA, UK
The theory behind solenoid-free microwave driven start-up in tokamaks
Choudhary, Sagar
Institute for Plasma Research, India
Gyrokinetic Transport in flat-Temperature Tokamak Plasmas
McClenaghan, Joey
General Atomics, USA
Integrating Gyrokinetic Flux Predictions with Ideal MHD Stability Boundaries
Costello, Paul
IPP Greifswald, Germany
Constrained optimal modes: tightening thermodynamic bounds on the linear growth rate of microinstabilities
Rivals, Nicolas
CEA, France
Understanding of the X-Point Radiator regimes in tokamaks through an example in the WEST device
De Gianni, Ludovica
CEA, France
Understanding Trapped Electron Modes in negative triangularity
Sengupta, Wrick
Princeton University, USA
Periodic Korteweg-de Vries soliton potentials generate quasisymmetric magnetic field strength in both vacuum and finite plasma-beta equilibrium
Devin, Emma G.
PPPL, USA
Nonlinear evolution of strongly driven perturbative kinetic instabilities
Schekochihin, Alex
University of Oxford, UK
Tutorial: "As simple as possible but not simpler": physics of turbulence and transport in fusion plasmas via reduced fluid models
Ekmark, Ida
Chalmers, Sweden
Runaway electrons in stellarators: Unlikely or unavoidable
Sun, Haomin
EPFL, Switzerland
The unusual dynamics of turbulent transport in spherical tokamaks with large field line pitch angle
Fitzgerald, Michael
UKAEA, UK
Conservation and destruction of alpha particle invariants in optimized stellarators
Thienpondt, Hanne
CIEMAT, Spain
Nonlinear critical gradients in W7-X: Insights from massive gyrokinetic simulations and experimental measurements of turbulent heat transport
Foster, Thomas
PPPL, USA
Analytical formulas for alpha-particle orbits in stellarators
Velasco, José Luis
CIEMAT, Spain
Tutorial: New avenues for stellarator design enabled by piecewise omnigenity
Goodman, Alan
IPP Greifswald, Germany
Searching for SQuIDs: Developments in the optimisation of Stable Quasi-Isodynamic Designs
Wang, Jialei
NIFS, Japan
Comprehensive simulations of bursting shear Alfvén waves in tokamaks and their control via phase space engineering with ICRF waves
Jurašić, Philipp
Proxima Fusion, Germany
Designing stellarator island divertors by controlling the island flux
Zhang, Kaiyu
IPP Garching, Germany
Exploring Tokamak Boundary Turbulence with GRILLIX Simulations: From L-Mode to H-Mode and the Quasi-Continuous Exhaust Regime

Varenna–Lausanne 2026 Conference Committee

The Scientific Committee selects speakers based on scientific excellence, while aiming to ensure a balanced program that reflects diversity in geographical location, professional background, and gender. The following lists show the current members of the Scientific Committee, in alphabetical order.

D. BORBA (Lisbon, Portugal)

E. BELLI (California General Atomics, USA)

I. CALVO (Madrid, Spain)

L. FIGINI (Milan, Italy)

G. FU (Zhejiang, China)

T. FÜLÖP (Chalmers, Sweden)

X. GARBET (Cadarache, France and NTU, Singapore)

R. GANESH (Bhat, IPR, India)

J.P. GRAVES (EPFL, CH and York, UK), Scientific Director

C.J. HAM (Culham, UK)

P. HELANDER (Greifswald, Germany), Chairman

S. HUDSON (Proxima Fusion, Germany)

M. HOLE (Canberra, Australia)

Y. KISHIMOTO (Naka, Japan)

M. MURAGLIA (Marseille, France)

R. MACKENBACH (EPFL, CH)

S. L. NEWTON (Culham, UK)

V.P. PASTUKHOV (Moscow, Russian Federation)

E. POLI (Garching, Germany)

F. PORCELLI (Torino, Italy)

O. SAUTER (EPFL, CH)

D. TSKHAKAYA (Prague, Czech Republic)

F. WAELBROECK (Austin, USA)

H.R. WILSON (UKIFS, UK)

A. WRIGHT (Wisconsin, USA)

F. ZONCA (Frascati, Italy)