Summary of IAEA Theory Papers on Energetic Particle Physics

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Summary of IAEA Theory Papers on Energetic
Particle Physics

• Guoyong Fu

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Statistics

• A total of 15 papers presented
• 5 talks, 10 posters
• 4 papers on low frequency modes (GAM,BAAE)
• 2 papers on nonlinear simulations of AE
• 2 papers on EP transport due to micro-
  turbulence
• 5 papers on EP-related physics in 3D geometry
• 1 paper on control of sawteeth by NBI.

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TH/4-1 Chapman, I.T. The Physics of Sawtooth
Stabilisation in Tokamak Plasmas

• The application of off-axis NBI can destabilise
  sawteeth which had previously been strongly
  stabilised by simultaneous on-axis heating. This
  is explained qualitatively through the role of
  passing energetic ions with a positive pressure
  gradient at the q1 surface.

4
Weak Fast Particle Transport due to micro
turbulence
TH/8-3 Angioni, C. Germany 20 Gyrokinetic
Simulations of Impurity, He Ash and Alpha
Particle Transport and Consequences on ITER
Transport Modelling
5
Weak Fast Particle Transport due to micro
turbulence
TH/P3-14 Chen, L. Gyrokinetic Simulation of
Energetic Particle Turbulence and Transport
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4 papers on low frequency modes (GAM, BAAE)

• TH/P3-7 Zonca, F. Kinetic Theory of Geodesic
  Acoustic Modes Radial Structures and Nonlinear
  Excitations
• TH/P3-11 Kolesnichenko, Y.I. Sub-GAM Modes in
  Stellarators and Tokamaks
• TH/P3-15 Fu, G.Y. Energetic Particle-induced
  Geodesic Acoustic Mode
• TH/5-2 Gorelenkov, N.N. Theory and Observations
  of Low Frequency Eigen-modes due to Alfvén
  Acoustic Coupling in Toroidal Fusion Plasma

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TH/P3-7 Zonca, F. Kinetic Theory of Geodesic
Acoustic Modes Radial Structures and Nonlinear
Excitations

• Geodesic Acoustic Modes (GAM) are shown to
  constitute a continuous spectrum due to radial
  inhomogeneities.
• The existence of a singular layer causes GAM to
  mode convert to short-wavelength kinetic GAM
  (KGAM) via finite ion Larmor radii analogous to
  kinetic Alfven waves (KAW). KGAM are shown to
  propagate radially outward consistent with
  experimental observations and numerical
  simulation results.
• KGAM can be nonlinearly excited by drift-wave
  (DW) turbulence via 3-wave parametric interactions

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TH/P3-11 Kolesnichenko, Y.I. Sub-GAM Modes in
Stellarators and Tokamaks

• Equations describing eigenmodes with the
  frequencies of the order of the geodesic acoustic
  frequency and the electron/ion diamagnetic
  frequency in toroidal plasmas are derived and
  analyzed.
• It is shown that there exist drift-sound
  eigenmodes and new drift-Alfven eigenmodes.
• It is shown experimentally that the modes
  rotating in different directions can be
  destabilized simultaneously, which agrees with
  theory predictions (W7AS).

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TH/5-2 Gorelenkov, N.N. Theory and Observations
of Low Frequency Eigen-modes due to Alfvén
Acoustic Coupling in Toroidal Fusion Plasma
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TH/5-2 Gorelenkov, N.N. Theory and Observations
of Low Frequency Eigen-modes due to Alfvén
Acoustic Coupling in Toroidal Fusion Plasma

• Due to large plasma beta in NSTX, characteristic
  frequency sweeping of RSAEs is suppressed.
• New low frequency modes (BAAE) are studied and
  observed in JET, NSTX and DIII-D. They exist in
  the BAAE gap with the frequency below GAM.
• Kinetic theory of BAAEs is formulated. It is
  shown that gap BAAEs are usually have smallest
  Landau damping in comparison with the sweeping up
  modes. If electron temperature exceeds thermal
  ion temperature BAAE dispersion is close to the
  MHD and has weak damping.
• Observed BAAE frequencies are low and within the
  experimental uncertainty agree with theory.

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TH/P3-15 Fu, G.Y. Energetic Particle-induced
Geodesic Acoustic Mode

• A new energetic particle-induced Geodesic
  Acoustic Mode (EGAM) is shown to exist. The mode
  frequency and mode structure are determined
  non-perturbatively by energetic particle kinetic
  effects.

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The mode width is determined by the particle
orbit width
r/a0.006
r/a0.016
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2 papers on nonlinear simulations of AE

• TH/P3-9 Todo, Y., Simulation Study of
  Interaction between Energetic Ions and Alfvén
  Eigenmodes in LHD
• TH/5-1 Vlad, G. Particle Simulation of Energetic
  Particle Driven Alfvén Modes

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TH/P3-9 Todo, Y., Simulation Study of
Interaction between Energetic Ions and Alfvén
Eigenmodes in LHD

• A numerical code that simulates the time
  evolution of energetic particles and AE mode
  amplitude and phase in a self-consistent way has
  been newly developed for three-dimensional
  equilibria such as LHD. In the simulation code,
  AE mode spatial profiles are assumed constant.
• Simulation with neutral-beam injection and
  collisions taken into account was carried out in
  the LHD equilibrium using the two TAE modes. It
  was demonstrated that Alfvén eigenmode bursts can
  be simulated with the new code.

15
TH/5-1 Vlad, G. Particle Simulation of Energetic
Particle Driven Alfvén Modes

• Abstract The results of hybrid MHD-particle
  simulations of the Alfven mode dynamics in a
  reversed-shear beam-heated DIII-D discharge are
  reported and compared with the experimental
  observations. Specific attention is devoted to
  the inclusion, in the numerical model, of
  nonlinear coupling between different toroidal
  mode numbers

16
5 papers on EP-related physics in 3D geometry.

• TH3-4 Spong, Energetic Particle Physics Issues
  for 3-dimensional Toroidal Configurations
• TH/P3-5 Biancalani, A. Shear Alfvén Wave
  Continuous Spectrum in the Presence of aMagnetic
  Island
• TH/P3-9 Todo, Y., Simulation Study of
  Interaction between Energetic Ions and Alfvén
  Eigenmodes in LHD
• TH/P3-11 Kolesnichenko, Y.I. Sub-GAM Modes in
  Stellarators and Tokamaks
• TH/P3-12 Yakovenko, Y.V. Effect of the Toroidal
  Asymmetry on the Structure of TAE Modes in
  Stellarators

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Plasma Energetic Particle Simulation Center
(PEPSC)

• PEPSC team
• PPPL G.Y. Fu (PI), S. Ethier, N. N. Gorelenkov,
• R. Samtaney
• Jianying Lang (12/01/08)
• J. Breslau, J. Chen (CEMM)
• IFS H. L. Berk, B. N. Breizman, J. W. Van Dam
• E. Chen (01/01/09)
• Univ. of Colorado Y. Chen, S. E. Parker
• ORNL Scott A. Klasky

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PEPSC Plan

• Upgrade M3D-K code extension to 3D domain
  decomposition for particles add source and sink.
  
• Build a new gyrokinetic/MHD hybrid code GKM
  (start from M3D-K) that uses gyrokinetic closure
  to include kinetic effects of thermal ions as
  well as energetic particles.
• Implement advanced numerical methods nonlinear
  implicit method, high-order finite elements, and
  workflow method. Also, optimize code speed.
• Explore reduced models for comparison with GKM.
• Apply codes to experiments for code validation
  and physics understanding.
• Apply GKM to ITER for simulations of alpha
  particle-driven high-n TAEs.

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Research Plan (2008-2009)

• Extend particle domain decomposition to 3D (scale
  to gt1000 processors)
• Add source/sink (CU and PPPL)
• Formulate nonlinear GKM model (PPPL and IFS)
• Build GKM0 (initial GKM version)
• M3D-K simulations of beam-driven Alfven modes in
  NSTX.