6th ITPA MHD Topical Group Meeting combined with W60 IEA Workshop on Burning Plasmas Session II MHD Stability and Fast Particle Confinement - PowerPoint PPT Presentation

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6th ITPA MHD Topical Group Meeting combined with W60 IEA Workshop on Burning Plasmas Session II MHD Stability and Fast Particle Confinement

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Title: 6th ITPA MHD Topical Group Meeting combined with W60 IEA Workshop on Burning Plasmas Session II MHD Stability and Fast Particle Confinement


1
6th ITPA MHD Topical Group Meeting combined with
W60 IEA Workshop on Burning PlasmasSession
IIMHD Stability and Fast Particle Confinement
  • General scope of the meeting
  • A major goal of this workshop on "Burning Plasma
    Physics and Simulations" is to provide a road map
    for burning plasma research
  • After the workshop we would like to have a short
    paper, outlining what our present knowledge is
    and where the gaps in our knowledge are ("where
    are we"), what we want to achieve ("where do we
    want to go"), and how we want to achieve this
    ("how do we get there")

2
Progress in key physics areas is leading to next
step burning plasma experiment
3
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4
MHD Stability and Fast Particle Confinement
  • Ripple effects
  • Low frequency MHD
  • fishbones, kBMs
  • Sawteeth and NTMs
  • Fast particle thermalisation
  • High frequency MHD (Alfvén)
  • Linear stability
  • Nonlinear development (redistribution and losses)
  • Nonperturbative modes (EPMs)
  • Diagnostic use
  • Possibilities for burn control

5
Ripple effects
  • Ripple losses in ITER?
  • Relatively well understood
  • Optimization of ferritic inserts in ITER to
    reduce ripple alpha losses in reversed shear
    configurations by more than one order of
    magnitude
  • Not an issue for ITER?

6
Low frequency MHD and fast particles
  • Interaction of fast ions with low frequency MHD
  • Fishbones nonlinear modeling in qualitative
    agreement with experiments
  • Linear theory of kBMs interchange modes well
    advanced
  • Neoclassical tearing modes
  • Questions being addressed
  • Mechanisms for seed island formation, mode
    coupling in NTM triggering
  • Island size after sawtooth crash (effect of
    a-stabilised sawteeth)
  • Sawtooth stabilisation by NBI
  • Quantitative effect of sawteeth on a distribution
  • Fast ion motion with NTMs (Hamamatsu)
  • Robust control method for (2,1) mode (Strait)
  • ECCD for NTM control (Modulated or continuous)
    (Guenter)

7
Fast particle thermalisation
  • Is ? slowing down classical?
  • Large effort to develop methods to simulate
    fusion ?s in plasmas without significant fusion
    reactivity
  • ?fast and R??fast ? ITER
  • vpart/vA ? ITER
  • But ? slowing down time/?E gtgt ITER and ?fast gtgt
    ITER
  • Interaction between drift turbulence and fast
    ions an open question

8
At the core of burning plasma physicsEffect of
collective instabilities on self-heating
tae
tei
9
High frequency MHD and fast particles Linear
stability
  • Most unstable fast ion driven modes in ITER
    scenarios?
  • Parameters that control mode stability?
  • Large amounts of data on instability thresholds,
    all ns (anisotropic fast ion distribution)
  • Experimental techniques to launch and detect
    stable modes large experimental databases of ???
    for low-n AEs, starting for intermediate/high ns
    (Fasoli, Snipes)
  • Drive and damping mechanisms qualitatively
    understood
  • Quantitative predictions on damping to be
    improved, especially in regimes in which fluid
    and kinetic models give different results
    (Guenter, Gorelenkov)
  • Methods for systematic expt.-theory comparison
    when many modes coexist

10
High frequency MHD and fast particles
Nonperturbative modes (EPMs)
  • Effect of Energetic Particle Modes well above
    marginal stability on ? profile?
  • Ex. of simulation of a-AE interaction ?
    redistribution

11
High frequency MHD and fast particlesNonlinear
wave-particle interaction
  • Redistribution and losses
  • Limits to ITER operational scenarios?
  • Self-consistent fast particle profile in ITER?
  • Significant progress in qualitative
    understanding, particularly in weakly nonlinear
    regime, where even some quantitative aspects are
    reproduced
  • Limited experimental data on fast ion
    redistribution and losses (difficulty in
    achieving large amplitudes and in diagnosing
    radial distribution of fast ions)
  • Todo, Gorelenkov, Takechi

12
High frequency MHD and fast particlesDiagnostic
use
  • Information from MHD spectroscopy?
  • Background plasma (e.g. Alfvén Cascades qmin(t))
  • Fast particle distribution
  • Potential for stand alone use and real time
    applications to be demonstrated

13
High frequency MHD and fast particlesPossibilitie
s for burn control
  • Burn control tools and methods?
  • Some building blocks based on control of fast
    particles and related modes (AEs ICRH) are
    being tested (e.g. at JET)
  • Attempts at simulating burning plasmas using NBI
    to mimic ? heating (JT-60U)
  • Otherwise open question

14
6th ITPA MHD Topical Group Meeting combined with
W60 IEA Workshop on Burning PlasmasSession II
MHD Stability and Fast Particle Confinement  
14.30 Introduction A Fasoli
14.40 TAE and EAE damping in JET A Fasoli
1455 TAE damping rates compared with NOVA-K J Snipes
15.15 Fast particle driven modes - a new gyrokinetic code with full orbits S Guenter
15.35 Alfvén Eigenmode stability with beams and alpha-particle profile quasilinear relaxation in ITER N Gorelenkov
15.55 Nonlinear evolution of Alfven eigenmodes in an ITER-like plasma Y Todo
16.15 Coffee
16.35 Fast particle confinement and TAEs in JT-60U M Takechi
16.55 CAEs on MAST L Appel
17.15 Fast ion motion perturbed by NTM magnetic island K Hamamatsu
17.35 ECCD feedback on NTMs on AUG S Guenter
17.55 2/1 NTM stabilisation on DIII-D T Strait
18.15 Discussion Led by A Fasoli
1930 Close
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