TORICTRANSP simulations of ICRH heating of JET plasmas

1
TORIC/TRANSP simulations of ICRH heating of JET
plasmas

• Summary of TORIC runs for JET (I. Voitsekhovitch)
  and discussion with TRANSP and ICRH experts (Yu.
  Baranov, J. Conboy, I. Jenkins, T. Johnson, D.
  Keeling, E. Lerche)

• Outline
• Brief information about TORIC
• TORIC namelist in TRANSP and TORIC related
  post-processing
• Benchmarking of old and new TORIC versions
• Benchmarking between TORIC and SPRUCE for
  minority heating
• Fundamental D heating with TORIC
• Mode Conversion simulations comparison with
  TOMCAT PION

2
What is TORIC?
TORIC is a FLR full wave code. It solves
Maxwells equations in the presence of plasma and
wave antenna. It does this with a fixed frequency
and a linear plasma response in a mixed
spectral-finite element basis. The oscillating
plasma current JP is considered as a moment of
the perturbed particle distribution from the
linearised Boltzmann eq. in the presence of the
electric field from the excited wave.
TORIC uses the FLR expansion to convert the
vector integro-differential Maxwell equation with
d/dt ? -i? into a 6-order partial differential
equation. This approximation retains the 2nd
harmonic wave frequency and is 2nd order in ?i.
TORIC works in combination with FP models
(FPPMOD, SSFPQL, CQL3D).
Refs M. Brambilla, PPCF 41, 1, (1999) M.
Brambilla and T. Krucken, NF 28, 1813 (1988) D.
G. Swanson, Phys. Fluids 24, 2035 (1981) P. T.
Colestock and R. J. Kashuba, NF 23 763 (1983) J.
C. Wright et al, PoP 11, 2473 (2004)
3
TORIC namelist in TRANSP
Suggested by Robert Budny, the convergency of
simulations with this namelist for JET shot has
been examined by MIT TORIC experts
NICRF8 ! ICRF model switch
(1new SPRUCE 5old SPRUCE, 8TORIC) ... NMDTORIC
31 ! N of poloidal modes Npol 2n-1, Npol is
calculated for given n RFARTR5.0 ! distance from
antenna to Faraday shield, cm ANTLCTR1.6 !
effective antenna propagation constant NFLRTR1 !
ion FLR contributions, 1 included, 0 ignored !
NFLRETR1 ! electron FLR contribution, was
commented in RB namelist ! FLRFACTR1.0 ! was
commented in RB namelist NBPOLTR1 ! poloidal
magn. field, 1 included, 0 ignored NQTORTR1 !
toroidal broadenning of plasma dispersion NCOLLTR
0 ! collisional contribution ENHCOLTR1.0 !
electron collision enhancement factor !
ALFVNTR(20) ad hoc collisional broadenning of
Alfven and ion-ion resonance ALFVNTR(1)0.0 ! 1
included, 0 ignored ALFVNTR(2)0.1 ! enhancement
factor ALFVNTR(3)3.0 ! value of abs((n//2-S)/R)
below which damping is added ALFVNTR(4)5.0 !
value of abs(w/(k//v_te)) below which damping is
calculated ! needed to maintain reasonable
values of RF current
TORIC documentation http//www.jet.efda.org/expe
rt/transp/Toric/Manual/frame.htm Parameter
variations for 66316 (H minority) RFARTR 2 -
5, ANTLCTR 1-1.6, ALFVNTR(1) 0 - 1,
ALFVNTR(3) 3 - 10 ? no effect on ICRH
deposition
4
Post-processing
The ICRH power deposition is transferred from
TORIC to TRANSP by default. For more detailed
information at given time steps (resonance
positions and heating of different species for
each antenna separately, wave fields, etc.) the
following lines should be added to the namelist
FI_OUTTIM(1) T1 ! T1 s is the time for first
output FI_OUTTIM(2) T2 ! T2 s is the time
for second output etc. TMAX9
Detailed results obtained with TORIC are saved in
Imp.tgz file. Steps to extract the TORIC
data tar xz f Imp.tgz (extracts the
files shotrunID_FI_TAR.GZ1 (2,3,etc.)
shotrunID_ICRF_TAR.GZ1 (2,3,etc.))
fi_gzn_unpack (creates directories
shotrunID_fi shotrunID_icrf. The
shotrunID_icrf directory contains the files
shotrunID_A_n-1Ntor_toric5.msgs (fppdata,
etc.), input equilibrium and plasma profiles. The
routines gfpprf and xfpprf can be used to look at
stored results)
5
Toric 4 / 5.2 Comparisons

• Toric 4.0 has been available for use with TRANSP
  for some years
• The latest Toric 5.2 code was obtained from
  Garching, and substituted for version 4 at the
  end of 2007. Regression testing uncovered a
  couple of bugs in the new code
• The current drive normalisation differs by 25
  between Torics 4 5.2 it is still unclear
  which version is correct.
• These differences raise doubts about the
  effectiveness of any regression testing of the
  latest version of the code, prior to its release
  ( see also http//www.jet.efda.org/expert/transp/T
  oric/index.htm).
• If the code is to play a significant role in
  analysis of the new ITER antenna at JET, then in
  house support by local ICRH experts will be
  required.

6
JET scenarios selected for benchmarking
1. H minority heating (66316) BT 2.6 T, Ipl
2.6 MA, nl ? 2e19 m-3, Te0 ? 4.8 keV 2. He3
minority heating in RS ITB plasma (69407) BT
3.45 T, Ipl 2.5 MA, nl lt 2.6e19 m-3, Te0 ? 6.5
keV 3. Fundamental D heating (68731) BT 3.3 T,
Ipl 2 MA, nl ? 2.5e19 m-3 4. Mode Conversion,
He3 minority, ITB (62077) BT 3.25 T, Ipl 2.6
MA, nl lt 3e19 m-3
66316
ICRH
NBI
69407
ICRH
NBI
LHCD
62077
NBI
68731
NBI
ICRH
LHCD
LHCD
ICRH
7
Benchmarking of old (TORIC/TRANSP) and new
(TORIC/TRANSP) versions for H minority heating

• - Total electron and ion heating power in perfect
  agreement
• Strong disagreement for ICRH electron heating
  profile
• It comes from disagreement from power absorbed
  by minorities

Pe at 6 s
Pe at 7.4 s
Wave power deposition on minority
Pi at 6 s
Pi at 7.4 s
Power from minority to electrons
ICRH electron and ion power depositions
8
Problem with resonance locations (ex. for 66316)
Wave frequency of A2/A3/A4 46.16/46.7/ 46.52
Mhz From _toric5.msgs files Main D A2
Fundam. resonance at X -168.291 cm - outside
the plasma on the HFS Harmonic resonance
at X -40.572 cm tangent to the surface r/a
0.52 on the HFS Beam D A2 Fundam. resonance at
X -168.291 cm - outside the plasma on the HFS
Harmonic resonance at X -40.572 cm tangent
to the surface r/a 0.52 on the HFS C
impurity A2 Fundam. resonance at X -168.291
cm - outside the plasma on the HFS
Harmonic resonance at X -40.572 cm tangent to
the surface r/a 0.52 on the HFS
similar
for A3 and A4 H minority A2 Fundam. resonance
at X -40.572 cm tangent to the surface r/a
0.520 on the HFS Harmonic resonance at X
224.605 cm - outside the plasma on the LFS A3
Fundam. resonance at X -43.822 cm tangent to
the surface r/a 0.553 on the HFS
Harmonic resonance at X 218.536 cm - outside
the plasma on the LFS A4 Fundam. resonance at X
-42.743 cm tangent to the surface r/a 0.542
on the HFS Harmonic resonance at X
220.547 cm - outside the plasma on the LFS
From tr.log file (simple estimation w/o
Doppler shift) Antenna 2 D harmonic 2 at R
333.7 cm, D_MCfi harmonic 2 at R 333.7 cm,
C12_6 harmonic 2 at R 333.7 cm, H_mino
harmonic 1 at R 333.7 cm.
Antenna 3 D harmonic 2 at R
336.6 cm, D_MCfi harmonic 2 at R 336.6 cm,
C12_6 harmonic 2 at R 336.6 cm, H_mino
harmonic 1 at R 336.6 cm.
Antenna 4 D harmonic 2 at R
335.6 cm, D_MCfi harmonic 2 at R 335.6 cm,
C12_6 harmonic 2 at R 335.6 cm, H_mino
harmonic 1 at R 335.6 cm.

9
Benchmarking of old (TORIC/TRANSP) and new
(TORIC/TRANSP) versions for He3 minority heating
Electron heating profile at 7 s
Total
Direct electron heating
Minority heating
Ion heating profile at 7 s
Direct ion heating
Fund. He3 resonance at r/a0.15 HFS (msgs)

• disagreement for total electron, ion and
  minority heating power as well as in Pe Pi
  deposition profiles
• discrepancy comes from different power absorbed
  on minority (like for 66316)

However, there is perfect agreement for 68731
(fund. D heating) where minorities are not
involved
10
Effect of re-normalisation of quasi-linear
operator (QLO) on power deposition for minority
heating
- ICRF wave codes specify both the damping power
density on minority fast ions, and the 2D wave
field (E, polarization, k?, kll). In theory, the
QLO coefficients are fully determined by the wave
field alone. - Because of differences in the
representation of fast ion distribution between
the FP model and wave code, the damping power
implied by QLO from the wave field alone may not
match the damping power expected by the wave
code, and the integrated profile will not match
the power-at-the-antenna that was specified to
wave code. - FPPMOD operator re-normalises the
original QL operator zone by zone while keeping
the total power constant. Low and upper limits of
normalisation constant are fixed in TRANSP. When
the normalisation constant exceeds one of these
limits it will be restricted by this limit, but
then the power should be re-distributed along the
radius to have the same total power. This creates
the distortion of deposition profiles and shift
of the maximum absorbed power with respect to
real resonance location.
old TORIC/TRANSP
new TORIC/TRANSP
PWAVEMIN (red) power damped on minority
calculated by TORIC PQSLMIN (blue) power
obtained with non-normalised QLO in TRANSP
PQLNORM power damped on minority after the
normalisation of QLO (scaled by PWAVEMIN/PQSLMIN)
11
Update of FPPMOD routine
Warning user should check the normalisation of
QLO (gfpprf ? xfpprf (last plot) or multigraph
RFHMIN_H (or _HE)) and compare original profile
of TORIC wave power deposited on minority,
non-normalised QL operator profile and normalised
QL operator by TRANSP FP module fppmod. The
profiles FWAVMIN and FQLNORM should
coincide. Immediate action Doug added the
minimum and maximum renormalization factors
"min_qlnorm" and "max_qlnorm" in the FPPMOD
namelist and raised the upper limit on the QL
re-normalisation from 3 to 20. To change these in
the FPPMOD namelist when running xfpprf from data
saved with FI_OUTTIM(...) in addition to the
values themselves one have to set mstate1 to
prevent the namelist changes from being
overwritten by the "state file" which is used
when xfpprf is run in this mode. Long-term
action include the limits for the normalisation
constants in the TRANSP namelist
12
Benchmarking between TORIC and SPRUCE for H
minority heating
This benchmarking has been done with the same
TRANSP version switching from SPRUCE to TORIC
Evolution of total powers
Power deposition at 6.6 s
Direct electron heating
Total absorbed power
Direct electron heating
Power to fast ions
Direct ion heating
Direct ion heating
Minority heating
Total power
Electron heating from minority
Ion heating from minority
Power to minority
13
Different power deposition in all channels ?
different electron and ion heating power profiles
QLO
6.6 s
Electron heating power profile
TORIC
TORIC
SPRUCE
Ion heating power profile
SPRUCE
SPRUCE
TORIC
14
Benchmarking between TORIC and SPRUCE for He3
minority heating (I)
Evolution of total powers
Power deposition at 7.5 s
Total absorbed power
Total
Direct electron heating
Direct electron heating
Direct ion heating
Minority heating
Minority heating
Direct ion heating
Electron heating from minority
Ion heating from minority
15
Benchmarking between TORIC and SPRUCE for He3
minority heating (II)
Electron heating power profile
TORIC
SPRUCE
Ion heating power profile
SPRUCE
TORIC
16
Fundamental D heating with TORIC (I)
Power deposition at 7.5 s
Evolution of powers
Total
Total
Direct electron
Direct ion heating
Fast ion
Direct ion
Direct electron heating
Minority
Fast ion
Minority ? electrons
Minority ? ions
17
Fundamental D heating with TORIC (II)
18
Mode Conversion case (62077) can be compared with
TOMCAT P. Mantica et al, PRL March 2006
Direct electron heating (FW)
Minority heating Minority to electrons
Minority to ions
Fast ion direct thermal ion heating
Smaller time step should be used
TORIC does not show mode conversion ? number of
poloidal modes should be strongly increased
19
Effect of the number of poloidal mode deposition
profiles at minimum (red pink) and maximum
(blue green) modulation amplitude obtained with
NMDTORIC31 (red blue) and NMDTORIC63 (pink
green)
Total absorbed power
Minority heating
Direct electron heating
Minority to electrons
Fast ion heating (small)
Minority to ions
Direct ion heating

• The results are weakly affected by the choice of
  poloidal modes
• Modulation affects direct electron and minority
  heating, but not the power given to electrons and
  ions from minority. Finally, only central
  electron heating is modulated

20
Electron and ion heating profiles at minimum (red
pink) and maximum (blue green) modulation
amplitude obtained with NMDTORIC31 (red blue)
and NMDTORIC63 (pink green)
21
Summary of simulation results and discussion

• Effect of inaccurate re-normalisation of QLO has
  been found and re-normalisation has been
  improved, but users should always check the
  re-normalisation
• There is still a problem with resonance locations
  in .msgs file
• These problems were not seen in Cmod test case ?
  JET discharges contributed to regression test
• Large difference between TORIC and SPRUCE for
  minority heating case negligible direct ion
  heating with TORIC (heating on second harmonic is
  not taken into account?), different heating
  profiles. Large and very localised central
  electron heating is not clear in ITB discharge.
  Benchmarking of SPRUCE and TORIC with the same
  number of modes is suggested.
• Fundamental heating edge absorption? More shots
  with proper antenna frequencies should be tested.
  The study of this scenario by Ernesto shows that
  mainly beam ions are heated by ICRH.
• Mode Conversion qualitatively in agreement with
  TOMCAT PION, but wrong resonance location in
  .msgs file and no MC. Suggestion of ICRH
  experts much larger number of poloidal modes (at
  least 200) should be used.

22

• Conclusion of TRANSP and ICRH experts
• TORIC does not provide an off the shelf
  solution to analysing JET RF pulses. At present
  we cannot explain or solve the problems found in
  TORIC simulations of JET plasmas, or the observed
  differences between the ICRH codes
• In the opinion of those present, development of
  ICRH modelling for JET will require the full time
  attention of an ICRH expert.