Page 1 - Impurity-ion rotation dynamics in C-2W

Goals
1. Analysis – interpretive modeling of C-2W experiment [1]
1. Infer plasma parameters and profiles from diagnostics
2. Estimate transport coefficients and confinement times
3. Integrated modeling to understand interactions between components
2. Simulation – predictive modeling of experiment
1. Validate models, suggest new operating scenarios
2. Predict behavior and help design next–step device
Public Private Partnerships
Current breakdown:
1. TAE in-house model development with emphasis on experimental interpretation and validation
2. Collaborations with Public entities with emphases on basic science and enabling technologies
• Collaboration with UCI GTC group for Kinetic micro-stability
• Collaboration with PPPL via INFUSE award for Kinetic global stability
• Other INFUSE awards in experimental team
• Participation in Exascale Computing Project Industrial Council
• DoE Leadership Computing Facility awards
• INCITE awards 2018 and 2019 at ALCF
• ALCC 2019/20 at ALCF and NERSC
Integrated Modeling Goal: Couple Enough Physics
Collaboration with PPPL via INFUSE award: Equilibrium and Global Stability
C-2W FRCs have enormous fast ion pressure, ~50% of total [1]
Collaboration with UC Irvine:
First Principles Simulation of Kinetic Microstability
Experiment finds Micro-Instabilities in SOL, not in FRC core [6]
à Validates theory [7,8] and global 1st principles simulation [9,10] @TAE: ANC code - see C.K. Lau et al, VP13.00018
• Blended Kinetic Simulations of Global Turbulent Transport
Global Transport: Hybrid MHD + Fast Ions
Q2D = Full Orbit MC + 2D thermal fluid
Global Transport physics
I! à Multi-species (fast ions + Hall MHD + neutrals)
à Self-organization and relaxation à Expander divertor physics
à Neutral transport
à See M. Onofri et al, APS 2019 Actuators
à Neutral Beam heating and current drive
à Electrode biasing effect on rotation
à Understandable model of interacting actuators and affect on 2D global transport
Coupled Ion and Neutral Transport
External Actuator Models
Coupled core and SOL
B ~ 0 regions; O-point and X-points; Self-organization Fully kinetic ions
Multi-species: fast p, thermal D, electrons, neutrals
Mirror sections; Loss cone physics
Expander Divertors; Parallel electron Dynamics, Pre-sheath, sheath
2D linear mode structure
@TAE – 3D Non-Linear Stability simulations with FPIC [4,5]
à Fast ion equilibrium from LR+MC code has fast ion “rings” at turning points at end of separatrix
à Non-linear saturation of n=1-4 modes observed
à See also F. Ceccherini et al, APS 2019
Linear eigenmode structure, 𝛿𝜙
Linear eigenmode structure, 𝛿𝜙
Electrode biasing; Rotation, Heating
RF
NB Injection;
Current drive & heating;
Pulsed power, Magnetics
@ UC-Irvine: GTC-X code [11]
Plasma Models
Acknowledgements
𝜔!×# = 0
1. H. Gota et al, Nuclear Fusion 59, 112009 (2019)
2. M. Tuszewski et al, Phys. Rev. Lett. 108, 255008 (2012)
3. E. Belova, et al. Phys. Plasmas 8, 1267 (2001)
4. F. Ceccherini, et al. APS DPP-Meeting PP.11.99 (2018)
5. S. Dettrick, et al. APS DPP-Meeting PP.11.97 (2018)
6. L. Schmitz et al, Nature Comm. 7, 13860 (2016)
7. M. Rosenbluth, N. Krall, N. Rostoker, Nucl. Fusion. Suppl, Pt 1, 143-150 (1962) 8. M. Binderbauer, N. Rostoker, J. Plasma Phys 56, 451 (1996)
9. D. Fulton, et al. Phys. Plasmas, 23, 012509 (2016)
10. C. Lau, et al. Nuclear Fusion 59, 066018 (2019)
11. J. Bao, et al. Phys. Plasmas, 26, 042506 (2019)
Simulations used the resources of DOE Office of Science User Facilities: National Energy Research Scientific Computing Center (DOE Contract No. DE-AC02-05CH11231) and Innovative and Novel Computational Impact on Theory and Experiment (INCITE) program at Argonne Leadership Computing Facility at Argonne National Laboratory (DOE Contract No. DE-AC02-06CH11357).
3D fast ion density isosurfaces
𝜔!×# = 0.57 = 𝛾$
(Figures from [6])
Simulation of Equilibrium, Stability, and Transport in Advanced FRCs
S.A. Dettrick1, D.C. Barnes1, E.V. Belova3, F. Ceccherini1, L. Galeotti1, S. A. Galkin1, S. Gupta1, K. Hubbard1, O. Koshkarov1, C.K. Lau1, Z. Lin2, Y. Mok1, A. Necas1, B. S. Nicks1, M. Onofri1, J. Park1, S.V. Putvinski1, L. S. Steinhauer1, T. Tajima1,2, W. Wang2, X. Wei2, K. Yakymenko1, P.N. Yushmanov1, and the TAE team
1 TAE Technologies, Inc., 19631 Pauling, Foothill Ranch, CA 92610; 2 University of California Irvine, Irvine, CA 92697, 3 Princeton Plasma Physics Laboratory, Princeton, NJ 08543
Contact: sean@tae.com Website: www.tae.com 62nd APS-DPP Meeting
à How does this change the equilibrium? @ PPPL - FRCIN code for HYM
HYM
Jb
fast
thermal
total
J φ
Jth
Radius (m)
Current density (A/m2)
Current density (a.u)
à Kinetic Grad-Shafranov equilibrium à Capability for NSTX-U and FRCs
@TAE - LR+MC code
→ →
Blended fully kinetic/gyrokinetic pusher allows efficient, cross-separatrix, global simulations
Unstable modes grow in the SOL where energy cascades from shorter to longer toroidal wavelengths; the smaller scale fluctuations can spread across the separatrix into the core
à
à à à
See L. Galeotti, VP13.00010 poster
Magnets and wall shaping
Thermal plasma species as fluids
Fast ions by Monte Carlo NB source/sink model
à Fast ion pressure anisotropic; not a flux function
400
300
200
100
0
LR+MC
MHD Modes can be stabilized in C-2U and C-2W experiments by combinationofendbiasingandneutralbeaminjection[2,1]
A Iondensity,ni(m-3)
Neutraldensity,n0(m-3)
Neutral density, n0 (m-3)
KNITPIC = Kinetic Neutral and Ion Transport by PIC
àStudy Ion current to electrode in different recycling regimes
àIonization, charge exchange àWall reflection coefficients
Ions Striking Electrode vs SOL source
B
A
Each point above is a different simulation run to equilibrium
à What more can we learn about stability boundaries in
presence of end biasing and large Pfast? δE @PPPL - 2D & 3D Linear Stability Simulation
with HYM code [3]
Fast Ions Can Drive Low Order Modes
à Linear 𝜹𝒇 simulations with unperturbed orbits
à Modes n=1 to 4 are driven by fast ion resonances. n=2 most unstable for beam parameters like C-2W
à In experiment, the same modes appear to saturate nonlinearly or be mitigated by applied sheared rotation
R,φ
δB
Z
à Nonlinear simulations with HYM to come
soon n=4
• Gyrokinetic Simulations of ITG instabilities in SOL
→ ITG saturates by self-generated zonal flows, which reduce ITG saturation
amplitude, turbulence eddy size, and the ion heat flux
→ Shear of equilibrium radial electric fields are found to reduce ITG linear growth rate, nonlinear fluctuation amplitude, and ion heat conductivity by tilting the turbulence eddies
→ See poster: X. Wei, W. Wang, Z. Lin, PO07.00001
àBifurcation to high recycling regime observed above a certain level of jet current
References
n=1
n=2
n=3
Wavenumber spectra [6]
Experiment (symbols, error bars) Simulation (lines, shaded areas)
B
Ion density, ni (m-3)
Electrostatic potential, 𝜹𝝓