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1 14th IAEA-TM, Fast ion modeling with phase space modifications, M. Podestà, Sep. 2015

Review of Theory Papers at 14th IAEA technical meeting on Engertic Particles in

Magnetic Confinement systems

Presentation by Herb Berk University of Texas at Austin Institute for Fusion Studies in Vienna, Austria Sept. 1-4, 2015


Cartoon of Stiff Critical Gradient


O-6: Gorelenkov Assumes Marginal Stability Independent of Velocity Space matches neutron deficit using marginality to TAE +BAAE (EPM) modes

Can we infer transport from marginal stability alone


Kick Model (Podesta O-1)


Podesta (O-1) Treatment of fast ion phase space evolution relevant for consistent integrated simulations •  Two models tested for fast ion transport in integrated simulations:

–  Ad-hoc diffusion model, purely radial diffusion –  Phase space resolved “kick” model

  Retains correlation in E, Pf variations from resonant interactions •  Ad-hoc model OK for global quantities (e.g. neutrons, stored energy) •  But: substantial differences observed for profiles, time evolution of

–  Fast ion density, NB-driven current –  Fast ion distribution function

NSTX #139048 classical

ad-hoc Db

kick model

Profiles of NB-driven current from TRANSP

0.0 0.5 1.0 1.5 2.0JNB peaking - classical

0.0

0.5

1.0

1.5

2.0

J NB p

eaki

ng -

incr

.

ad-hoc Db

kick model

JNB peaking – classical transport

J NB p

eaki

ng –

incr

emen

tal t

rans

port


Neutron Deficit Reproduced


R. Waltz O-3


Heidbrink (I-3)


Guoyong Fu (I-6)


As frequency Pφ & E change

Pφ - nE/ω =constant (n=1 for fishbone)


X. Wang (I-9)


Surprise element, chirp without bucket?

chirp time ~ ½ trapping time; Constraint requirement |(dω/dt)/(ωb)2| <1 & nearly constant


Gogaccia & Vlad (P-30) Also see: M. Cole: (I:12);

NON-LINEAR GYROKINETIC CODE FOR REALISTIC TOKAMAK FOR HAS SPECIALIZED IN EPM & NONLINEAR EFFECTS


A. Bierwage (I-10) Introductory Talk that Asks the question of whether we can heat ions having unstable beta Alfven waves heat plasma by simultaneously resonating with acoustic branch (kinetically ion Landau damping)

See also Biancalani-(I-7) Attempting formulate a very generalized set of nonlinear kinetic equations.


Y. Todo (O-19)


Y. Todo

•  Beam deposition power (PNBI) scan was performed with multi-

phase hybrid simulation for DIII-D experiments. •  It was found in the simulation results:

– Fast-ion confinement degrades steadily with increasing power.

– Normalized fast-ion pressure profile converges to a “stiff” profile as the phase space is covered by the transport regions with PNBI increase.

– For the “stiff” profile, the whole phase space should be fully covered by the overlapped transport regions up to the particle loss location.

– Transport barrier exists at the edge. Careful modeling of the edge transport and particle loss is important. 17


Puzzle: How are avalanches explained??

Lauber: P-27

Asdex data

NSTX- Data


P. Rodrigues (O-11) Can anything be done to quench alpha driven Alfvenic Instability


J. Ferreira (P-22)

In this case continuum is very well aligned


D. Spong (O-16)

Stellarator, appears much harder calculation but often very similar; but with additional gaps


Melnikov (0-18) Chirping measured with HIBP on TJ-II stellarator

HIBP Bpol

High coherence (Coh ~ 0.9) between Bpol oscillations (HIBP) at = 0.6 and Mirnov probes signals is observed for chirping modes.

CohHIBP MP

MP Bpol

22

<ne> < 0.6 x1019 m-3


D. Pfefferle (I-4) Ripple due to toroidal field coils in Demo


How to analyze ripple?


Avalanche from relativistic “knock ons” (Rosenbluth & Putvinski) Papers: G. Papp O-21; A. Stahl (P-31) Z. Chen O-22 (runaways in J-TEXT tokamak)

Electron Runaways


G. Papp (O-21)


FINIS

29 14th IAEA-TM, Fast ion modeling with phase space modifications, M. Podestà, Sep. 2015 Supported by DOE contract no. DE-AC02-09CH11466

M. Podestà, M. Gorelenkova, E. Fredrickson, N. Gorelenkov, R. White – PPPL, Princeton USA

Acknowledgements: NSTX-U and DIII-D Energetic Particles groups

Effects of fast ion phase space modifications by instabilities on fast ion

modeling

14th IAEA-TM on Energetic Particles Vienna, Austria

September 1-4 2015


One scenario for particle containment (Berk-Breizman)

One scenario for particle containment (Berk-Breizman)


M. Schneller (O-8)

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