2020 Summer Team Meeting

Hidden Symmetries and Fusion Energy
(Virtual) Annual Team Meeting
August 3-7, 2020

Monday, August 3: Overviews  
   Time (UTC+4) Topic (Video Link) Speaker: Presentation (Slides Link)
8:00~9:00 AM Overview:
   MHD Overview
J. Loizu: Overview and Perspectives of MHD Research
Z. Qu
9:00~10:00 AM Overview:
   Nonlinear Dynamics
R. MacKay: Progress and Problems in Nonlinear Dynamics
J. Meiss: Near-Axis Expansions
10:00~10:30 AM Break  
10:30~11:30 AM Overview:
G. Stadler: Optimization for Stellerators
D. Bindel
11:30AM~12:30 PM Overview:
P. Helander: Known and Unknown in Stellarator Confinement (pptx)  (pdf)
E. Stenson: Envisioning EPOS: Electrons and Positrons in an Optimized Stellarator
12:30~01:00 PM Break  
01:00~02:00 PM Overview:
M. Landreman: SIMSOPT Overview
Tuesday, August 4: Breakout Sessions  
08:00~10:00 AM Breakout: MHD
   (Moderator: J. Loizu)
A. Cerfon: Progress and Challenges For the Robust Calculation of Equilibrium Configurations in BIEST and NSTAB
S. Hudson: An introduction to the free-boundary algorithm in the SPEC code
A. Baillod: Bootstrap current effect on classical stellarator beta limits with SPEC
A. Kumar: SPEC as 3D MHD stability code
A. Golab: Distance of Coils from Plasma Boundar
08:00~10:00 AM Breakout: Optimization
   (Moderator: G. Stadler)
A. Giuliani: Direct gradient-based coil design in vacuum fields: optimization for quasi-symmetry
F. Wechsung: Direct gradient-based coil design in vacuum fields: stochastic optimization
S. Glas: Optimization Under Uncertainty
A. Geraldini: Computing Magnetic Island Width Sensitivity 
10:00~10:30 AM Break  
10:30 AM~12:30 PM Breakout: Confinement
   (Moderator: P. Helander)
A. Boozer: Stellarators with Annular Confinement
J. Burby: Fast Neural Pointcare Maps
R. Jorge: The Use of Near-Axis Magnetic Fields for Stellarator Turbulence Simulations
G. Roberg-Clark: Turbulence optimization without turbulence
12:30~01:00 PM Break  
     Cross-Cutting Topics  
01:00~02:00 PM Quasi-Symmetric
3D Equilibria:

  How To Construct Them?
   (Moderator: A. Bhattacharjee)
D. Ginsberg: On Quasisymmetric Plasma Equilibria With Small Force
M. Landreman: Update On Near-Axis Quasisymmetry Construction, And Suggested Research Questions
E. Rodriguez: Avoiding the problem of Overdetermination in Quasisymmetric Near-axis Expansions: Anisotropic Solution
G. Plunk: Deforming A Tokamak Toward QAS
R. Mackay: Conditions For Quasi-Symmetries, Killing Field Or Kovalevskaya, And Generalised Grad-Shafranov Equations
01:00~02:00 PM Stochastic Optimization:
Theory and Practice
   (Moderators: D. Bindel/G. Stadler)
J. Lobsien: Improvements on Stochastic Stellarator Coil Optimization
F. Wechsung: Modeling of coil uncertainties and risk-neutral designs (no slides)
T. Pederson: Comments on building coils and resulting uncertainties
Wednesday, August 5: Breakout Sessions (Continued)  
8:00~10:00 AM Breakout: Nonlinear Dynamics
   (Moderator: J. Meiss)
Converse KAM
  R. MacKay: Formulation and Examples
  N. Duignan: Converse KAM for Foliations
Integrability of GC motion
  N. Kallinikos: First-Order Symmetries 
  E. Rodriguez: Weak Quasi-Symmetry
Near-Axis Expansions
  R. Jorge: Near-Axis Expansions to Arbitrary Order
  W. Sengupta: Mercier-Weitzner Formulation 
  J. Burby: Near-axis magnetic coordinates for integrable magnetic fields
  A. Boozer: Cantori, Turnstiles, and Divertors
10:00~10:30 AM Break  
10:30 AM~12:30 PM Breakout: SIMSOPT
   (Moderator: M. Landreman)
B. Medasani: Guidelines for Simsopt Development
C. Zhu: Python wrapper for Fortran legacy codes
E. Paul: Gradient-based fixed-boundary optimization of VMEC and SPEC equilibria
B. Faber: Towards a modular, high-performance, scalable stellarator optimizer
12:30~01:00 PM Break  
     Cross-Cutting Topics  
01:00~02:00 PM Non-Ideal Stability
   (Moderator: P. Helander)
J. Loizu: Direct Prediction of Saturated Island Widths using SPEC
A. Zocco: Sawtooth physics in W7-X
D. Spong: Optimizing for Energetic Particle Instability Suppression
Thursday, August 6: Cross-Cutting Topics  
08:00~10:00 AM Optimizing EPOS:
A Grand Challenge Problem

   (Moderator: E. Stenson)
08:00~10:00 AM Diagnostics for MRxMHD Codes and Integration Strategies Into SIMSOPT
   (Moderator: Z. Qu)
Z. Qu: Cross-cutting discussion: MRxMHD tools, nonlinear dynamics diagnostics and SIMSOPT
10:00~10:30 AM Break  
10:30 AM~12:30 PM Divertors: What directions should we pursue?
   (Moderator: P. Helander)
Y. Feng: Island Divertors
A. Bader: Non-resonant divertors
T. Pedersen: Non-divertor exhaust solutions
12:30~01:00 PM Break  
01:00~02:00 PM Diagnostics to Measure
Flux Surface Quality/Islands

   (Moderator: M. Landreman)
Friday, August 7: Summaries and Goals for the Next year and Beyond  
09:00-09:25 AM SIMSOPT
   M. Landreman
09:25~09:50 AM Nonlinear Dynamics
   J. Meiss
09:50~10:15 AM Optimization
   G. Stadler
10:15~10:45 AM Break  
10:45~11:10 AM MHD
   J. Loizu
Summaries and Goals
11:10~11:35 AM Confinement
   P. Helander
11:35 AM~12:30 PM Finalizing Goals/Milestones
   A. Bhattacharjee