Title: 6th ITPA MHD Topical Group Meeting combined with W60 IEA Workshop on Burning Plasmas Session II MHD Stability and Fast Particle Confinement
16th 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")
2Progress in key physics areas is leading to next
step burning plasma experiment
3(No Transcript)
4MHD 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
5Ripple 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?
6Low 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)
7Fast 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
8At the core of burning plasma physicsEffect of
collective instabilities on self-heating
tae
tei
9High 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
10High 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
11High 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
12High 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
13High 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
146th 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