Measurements of the deuterium ion toroidal rotation in the DIII-D tokamak and comparison to neoclassical theorya)

TLDR: Luxon et al. as mentioned in this paper measured the main ion rotation in deuterium plasmas, particularly in regions of the plasma with steep pressure gradients where very large differences can be expected between bulk ion and impurity rotation.

Abstract: Bulk ion toroidal rotation plays a critical role in controlling microturbulence and MHD stability as well as yielding important insight into angular momentum transport and the investigation of intrinsic rotation. So far, our understanding of bulk plasma flow in hydrogenic plasmas has been inferred from impurity ion velocity measurements and neoclassical theoretical calculations. However, the validity of these inferences has not been tested rigorously through direct measurement of the main-ion rotation in deuterium plasmas, particularly in regions of the plasma with steep pressure gradients where very large differences can be expected between bulk ion and impurity rotation. New advances in the analysis of wavelength-resolved Dα emission on the DIII-D tokamak [J. L. Luxon et al., Fusion Sci. Technol. 48, 807 (2002)] have enabled accurate measurements of the main-ion (deuteron) temperature and toroidal rotation. The Dα emission spectrum is accurately fit using a model that incorporates thermal deuterium char...

Figures

FIG. 4. Profiles of absolute brightness FIDA Da emission intensity, beam Da emission intensity, and beam neutral density fractions for three times as the plasma density is ramped from (a) 2.5, (b) 4.5, and (c) 6.7 1019 m 3 at fixed beam power. Broken lines indicate modeled emission from FIDAsim.

FIG. 11. Bulk ion collisionality regime and poloidal flow velocity for Fig. 8 at 2130 ms. (a) The main-ion collisionality and the three collisionality regimes. (b) Poloidal flow computed with the NCLASS code (dash-dot), force balance relation Eq. (4) (solid), and the pure plasma banana regime approximation Eq. (2) (dashed). The ion (Vh > 0) and electron diamagnetic directions are indicated.

FIG. 12. (a) Safety factor value at the magnetic axis q0 and minimum safety factor qmin. Periods where q0 > qmin indicate reversed central magnetic shear. (b) Ion temperature evolution displaying core barrier formation when the central magnetic shear is reversed. (a) and (b) Times of rational qmin ¼ 2 crossing and sustained reversed shear are indicated by shaded region.

FIG. 5. Comparison of active spectral data with forward modeling with the FIDAsim. The sum of halo and DCX intensity is in good agreement with the experimentally measured thermal spectral radiance.

FIG. 6. Determination of deuterium temperature and toroidal rotation by correcting apparent values. (a) and (b) Profiles of apparent temperature and velocity from both co-Ip and ctr-Ip viewing Da systems, and spline fit of carbon temperature and carbon corrected velocity. (c) and (d) Profiles of corrected temperature and toroidal velocity, and carbon profiles [same as (a) and (b)].

FIG. 7. Variation of the apparent velocity correction for matched co and counter viewchords as the ion temperature is increased. At higher temperatures, the difference between apparent velocities from co and counter viewing systems becomes large.

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UC Irvine
UC Irvine Previously Published Works
Title
Measurements of the deuterium ion toroidal rotation in the DIII-D tokamak and comparison
to neoclassical theory
Permalink
https://escholarship.org/uc/item/0x94t54g
Journal
Physics of Plasmas, 19(5)
ISSN
1070-664X
Authors
Grierson, BA
Burrell, KH
Heidbrink, WW
et al.
Publication Date
2012-05-01
DOI
10.1063/1.3694656
Copyright Information
This work is made available under the terms of a Creative Commons Attribution License,
availalbe at https://creativecommons.org/licenses/by/4.0/
Peer reviewed
eScholarship.org Powered by the California Digital Library
University of California

Measurements of the deuterium ion toroidal rotation in the DIII-D
tokamak and comparison to neoclassical theory
a)
B. A. Grierson,
1,b),c)
K. H. Burrell,
2
W. W. Heidbrink,
3
M. J. Lanctot,
4
N. A. Pablant,
1
and W. M. Solomon
1
1
Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543, USA
2
General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
3
University of California, Irvine, California 92697, USA
4
Lawrence Livermore National Laboratory, Livermore, California 94551, USA
(Received 16 December 2011; accepted 30 January 2012; published online 28 March 2012)
Bulk ion toroidal rotation plays a critical role in controlling microturbulence and MHD stability as
well as yielding important insight into angular momentum transport and the investigation of
intrinsic rotation. So far, our understanding of bulk plasma flow in hydrogenic plasmas has been
inferred from impurity ion velocity measurements and neoclassical theoretical calculations.
However, the validity of these inferences has not been tested rigorously through direct measurement
of the main-ion rotation in deuterium plasmas, particularly in regions of the plasma with steep
pressure gradients where very large differences can be expected between bulk ion and impurity
rotation. New advances in the analysis of wavelength-resolved D
a
emission on the DIII-D tokamak
[J. L. Luxon et al., Fusion Sci. Technol. 48, 807 (2002)] have enabled accurate measurements of the
main-ion (deuteron) temperature and toroidal rotation. The D
a
emission spectrum is accurately fit
using a model that incorporates thermal deuterium charge exchange, beam emission, and fast ion D
a
(FIDA) emission spectra. Simultaneous spectral measurements of counter current injected and co
current injected neutral beams permit a direct determination of the deuterium toroidal velocity.
Time-dependent collisional radiative modeling of the photoemission process is in quantitative
agreement with measured spectral characteristics. L-mode discharges with low beam ion densities
and broad thermal pressure profiles exhibit deuteron temperature and toroidal rotation velocities
similar to carbon. However, intrinsic rotation H-mode conditions and plasmas with internal
transport barriers exhibit differences between core deuteron and carbon rotation which are
inconsistent with the sign and magnitude of the neoclassical predictions.
V
C
2012 American Institute
of Physics.[http://dx.doi.org/10.1063/1.3694656]
I. INTRODUCTION
Plasma toroidal rotation is generally considered a stabi-
lizing mechanism for deleterious magnetohydrodynamic
(MHD) instabilities such as the resistive wall mode
(RWM)
1,2
and neoclassical tearing mode (NTM),
3–5
as well
as contributing to E  B shear stabilization of turbulence
6
through the radial electric field E
r
. Intrinsic rotation,
7–9
which is toroidal rotation in absence of direct momentum
input, has been observed in many devices. Intrinsic rotation
may play a crucial role in determining the stability and trans-
port of future larger devices, such as ITER, with relatively
low torque provided by neutral beam injection.
10
In modern tokamaks, an impurity species is typically
used for the measurement of ion temperature and plasma
rotation in the toroidal and poloidal direction.
11,12
However,
neoclassical theory
13–15
predicts differences between the to-
roidal rotation of the main ions and impurities due to finite
poloidal flow and pressure gradients. In order to assess the
intrinsic rotation of the bulk ion species and extrapolate to
the rotation characteristics of future high performance
plasmas, direct measurements of the bulk ion toroidal rota-
tion are required.
Preliminary measurements which demonstrated the feasi-
bility of deuterium main-ion toroidal rotation measurements
in the core of DIII-D plasmas utilized a comprehensive spec-
tral fit model which incorporated all photoemission sources,
and complementary views of co and counter current directed
neutral beams.
16
Subsequently, the use of a fully three-
dimensional simulation of the photoemission sources, FIDA-
sim,
17
accurately reproduced the intensity of all processes,
and magnitude of cross-section distortions reported in Ref. 16.
A profile diagnostic which covers the plasma region from
magnetic axis to edge has been constructed to directly test the
neoclassical theory of differential toroidal rotation between
bulk ions and impurities in DIII-D. Due to the convoluted na-
ture of neutral beam attenuation, beam emission, charge
exchange, and halo neutral diffusion on plasma profiles, an
integrated modeling framework is employed with multiple
cross-checks to eliminate errors in interpretation of the
measurements.
This paper continues in Sec. II with the experimental con-
figuration and diagnostic specifications chosen to make neu-
tral beam induced spectroscopic measurements. Section III
a)
Paper NI2 5, Bull. Am. Phys. Soc. 56, 183 (2011).
b)
Invited speaker.
c)
Electronic mail: bgriers@pppl.gov.
1070-664X/2012/19(5)/056107/14/$30.00
V
C
2012 American Institute of Physics19, 056107-1
PHYSICS OF PLASMAS 19, 056107 (2012)

provides a brief overview of the technique of charge-
exchange and recombination (CER) spectroscopy for meas-
uring ion temperature and rotational velocity, as well as the
additional diagnostic information provided by the D
a
spec-
trum. Interpretation of the measurement is aided by the unique
neutral beam viewing configuration and three-dimensional
atomic modeling. Measurements of ion temperature and toroi-
dal velocity of deuterium and carbon in an L-mode discharge
are presented in Sec. IV, including the demonstration of
atomic corrections to the results of spectral fitting. Section V
provides a brief introduction into the neoclassical theory of
differential toroidal rotation between fuel ions and impurity
ions. Section VI displays measurements of the intrinsic toroi-
dal rotation of deuterium and carbon ions in H-mode plasmas
heated by electron cyclotron heating (ECH). Differences in
the toroidal rotation of the two ions species are evident, and
discrepancies with the neoclassical predictions are exposed.
Discussion of the influence of deuterium poloidal flow is pre-
sented. Section VII displays deuterium and carbon toroidal
rotation in the presence of an internal transport barrier and a
“notched” velocity profile near the radial region of steepest
pressure gradient. Similar discrepancies with the neoclassical
theory are exposed. Conclusions are provided in Sec. VIII.
II. EXPERIMENTAL CONFIGURATION AND
DIAGNOSTIC SPECIFICATIONS
A multi-chord profile diagnostic used in this work was
installed on the DIII-D tokamak
18
(R ¼ 1.66 m, a ¼ 0.67 m)
for measurement of core deuterium temperature and rotation.
A plan view of the tokamak and CER systems are displayed
in Fig. 1 with standard operation of plasma current I
p
and to-
roidal field B
T
being counter-clockwise and clockwise,
respectively, when the tokamak is viewed from above. All
sixteen of the sightlines are directed in the ctr-I
p
direction.
The profile diagnostic views intersect neutral beams which
inject both in the co-current and counter-current direction.
With independent views of the co and counter beams at the
same major radius, the true toroidal rotation velocity and
associated charge-exchange cross section correction can be
calculated,
19
and the sign and magnitude of the correction
can be compared to atomic modeling. Each neutral beam has
two ion sources directed at different angles, identified by
“RT” and “LT” for right or left ion source. The sixteen main
ion viewing chords intersect the 30

LT and 210

RT neutral
beams at matched radii pairs, spanning R ¼ 170.48 to
218.64 cm. Impurity CER channels which measure carbon
emission share the same major radius values with a small
elevation difference of approximately 4 cm. The neutral
beams are modulated to discriminate the spatially localized
“active” emission (defined in Sec. III) for determining tem-
perature, rotation, and density, and beam modulation is a
requirement for this measurement.
The photoemission from the tokamak is collected and
focused by f/4.0 lens optics and transmitted through
1500 lm core diameter fiber to McPherson 2/3 m spectrome-
ters. The visible light is dispersed by a 1200 g/mm grating
and collected by a CCD camera which is 768 pixels wide.
Each square pixel has an 18 lm width. In the first order, the
spectral reciprocal dispersion is 0.180 A
˚
/pixel. Spectral ac-
quisition is precisely timed such that the trigger for neutral
beam turn-on and CCD trigger occur simultaneously, ena-
bling clean “timeslice subtraction,” described in Sec. III.
Spectra are typically obtained at integration time of 2.5 ms.
Wavelength calibration for dispersion and fiducial (zero
of rotation) is performed after each tokamak discharge by
using a neon calibration lamp located at the diagnostic port.
Three neon lines at wavelengths 6506.5218 A
˚
, 6532.8824 A
˚
,
and 6598.9528 A
˚
(available from NIST) are used for shot-to-
shot calibration of dispersion and wavelength fiducial of
6561.03 A
˚
. While the dispersion does not change shot-to-
shot, there can be very slight drifts in the precise fiducial
location due to temperature fluctuations in the room which
houses the spectrometers and CCD cameras, necessitating
immediate waveleng th calibration following each shot. The
drift can result in as much as 1.0 km/s variation between sub-
sequent shots if uncompensated for. Additionally, the illumi-
nation of the spectrometer from the calibration lamp differs
slightly from the illumination from the beam-plasma interac-
tion. To compensate for this, the neutral beams are fired into
the tokamak pre-filled with neon gas. Neon excitation spectra
from beam interaction are analyzed to determine the offset
between tokamak illumination and calibration lamp illumi-
nation. The offset results in a correction of approximately
0.2 km/s. Data acquisition begins just prior to the breakdown
phase of the discharge, and the first D
a
spectrum of signifi-
cant intensity is fit. This breakdown D
a
photoemission pro-
vides further confirmation of accurate velocity fiducial, due
to the breakdown emission at the rest wavelength. Finally,
because the spectrometers are scannable to different wave-
lengths, the main-ion CER system has been tuned to the car-
bon C
þ6
(n ¼ 8 ! 7) transition to evaluate any systematic
differences between the main-ion and impurity CER sys-
tems, and none of significance has been found.
White light exposure provides the intensity response to
a broadband light source and is compensated for in the spec-
tral analysis. Absolute intensity calibration is performed with
FIG. 1. Top-down view of the DIII-D tokamak displaying three neutral
beam lines and CER sightlines. Viewchords of carbon (shaded) and main-
ion (lines) system core viewchords indicated viewing co-I
p
and counter-I
p
neutral beams.
056107-2 Grierson et al. Phys. Plasmas 19, 056107 (2012)

a calibrated integrating sphere oriented inside the vacuum
vessel along the neutral beam path. Absolute calibration is
performed prior to plasma operations and after operational
campaign with manned vessel entry.
III. IMPURITY AN D MAIN-ION CHARGE EXCHANGE
RECOMBINATION SPECTROSCOPY
Measurement of plasma toroidal rotation on many devi-
ces is accomplished by high power neutral beam injection
enabling a technique known as CER spectroscopy.
11,12
CER
which employs intrinsic impurities is used due to the relative
simplicity of the spectrum near the transition wavelength
and short lifetime of the excited states. On the DIII-D
tokamak, the fully stripped impurity carbon C
6þ
(n ¼ 8!7)
transition spectrum near 5290.50 A
˚
is dominated by two
Gaussian shapes which represent the cold edge and hot core.
This two-Gaussian shaped spectrum can be reduced to a
single Gaussian by modulation of the neutral beams and per-
forming timeslice subtraction, removing the “passive” edge
emission and obtaining the spatially localized “active” emis-
sion isolated to the region of the plasma where the viewchord
and neutral beam cross. Here, we define “passive” emission
as emission from the plasma edge and “active” emission fol-
lowing charge capture from a beam neutral to thermal ion.
The “active” emission is obtained by taking the difference
between the spectrum acquired when the beam is on and
when the beam is off, eliminating the passive contribution to
the photoemission.
Fitting of the charge-exchange spectrum results in an
apparent temperature and velocity from the Doppler width
and line shift that is different from the true temperature and
velocity, due to the energy dependence of the charge-
exchange cross-section.
20,21
The cross-section effect results
in a false line-shift which scales with the ion temperature
and with the viewing angle with respect to the neutral beam.
The measured apparent velocity can be rep resented as
V
app
¼ V
true
þ a
^
V
beam
, where a is a scalar quantity which
depends on the atomic cross-section and ion temperature,
and
^
V
beam
is the unit vector along the neutral beam. Correct-
ing for atomic physics considerations on toroidal and poloi-
dal flow measurements has become standard practice in
modern tokamaks and the reader is referred to the followin g
Refs. 11 and 19–25.
In contrast to the impurity spectrum, the spectrum near
the D
a
n ¼ 3!2 transition of 6561.03 A
˚
contains seven
complex features with distinct physical origins. Photoemis-
sion from the tokamak edge contains bright “passive” emis-
sion from (1) cold electron impact excited edge neutral gas
outside the scrape-off-layer (SOL), (2) warm edge emission
inside the SOL due to charge-exchange with thermal neutral
deuterium, as well as (3) two impurity lines of CII. The SOL
is the region between the last closed flux-surface and the vac-
uum vessel with a large neutral deuterium gas concentration,
and emission from (1) and (2) can be minimized by a large
gap between the separatrix and the vessel wall, as well as
reduced gas fueling. The temperature range of the edge emis-
sion is significantly lower than inside the plasma and the
emission occurs near the rest wavelength of the atomic tran-
sition, thus being distinguished from the “active” emission.
The “active” photoemission from the plasma interior associ-
ated with neutral beam injection contains (4) direct charge
exchange (DCX) emission between the beam neutrals and
the thermal deuterium ions, (5) “halo”
17,26,27
neutral emis-
sion from the excited product of charge-exchange between
the direct charge-exchange thermal neutral and thermal ions,
(6) charge exchange emission between the beam and fast
ions D
a
(FIDA), as well as (7) emission from the beam neu-
trals themselves. Direct charge-exchange and halo charge-
exchange emission appear as a single feature in the observed
spectrum. The former is distorted by the energy dependence
of the charge-exchange cross-section, and the latter emits
with the true local plasma temperature and rotation velocity,
albeit from a slightly larger spatial volume due to spatial dif-
fusion before ionization. The general effect of the halo is to
reduce the magnitude of the apparent velocity shift away
from the true velocity. The D
a
spectrum presents an enor-
mous amount of information which can be exploited for its
diagnostic potential and displays in excess of 30 spectral fea-
tures which need to be fit self-consistently.
26
An example of the D
a
spectrum and complete fit is pre-
sented in Fig. 2. This is a view of the co-I
p
beamline 30 LT
in an L-mode discharge with line averaged electron density
2  10
19
m
3
, central ion temperature of 1.5 keV, and toroi-
dal rotation near 5 km/s. The largest feature is the thermal
charge-exchange emission, which is fit by a single Gaussian
shape convolved with the instrumental function. The thermal
charge exchange emission contains the bulk temperature,
apparent velocity and density through the width, line shift,
and intensity of the Gaussian. Spectral fitting is performed in
pixel, rather than wavelength. The temperature of the emit-
ting ion is T
i
¼
1
2
mc
2
ðDw=k
0
Þ
2
, where m is the ion mass, c is
the speed of light, w is the Gaussian width, D is the spec-
trometer reciprocal dispersion (A
˚
/pixel), and k
0
is the rest
FIG. 2. Complete fit to active D
a
spectrum obtained by timeslice subtrac-
tion. The fit model incorporates the thermal charge-exchange feature local-
ized between channels 280–450, beam emission of 81 kV injection
indentified as full, half, and third, fast-ion emission (FIDA) and small contri-
butions from edge D
a
and carbon (CII). The spectral data are displayed in
black and sum of all contributions displayed in red. The low amplitude and
uniform weighted residuals is characteristic of a high quality fit.
056107-3 Grierson et al. Phys. Plasmas 19, 056107 (2012)

wavelength of the atomic transition. The line-of-sight (LOS)
apparent velocity is computed by V
app
los
¼ cDpD=k
0
, where
Dp is the difference between the fit pixel value and the fidu-
cial pixel value at 6561.03 A
˚
. The toroidal velocity V
app
u
is
computed by dividing the LOS velocity by the cosine of the
angle the viewchord makes with the toroidal direction at the
beam crossing.
The second largest feature is the beam emission which
is fit using the B-Stark model, detailed in Refs. 28–30. The
beam emission fit contains the beam neutral density of the
three energy components (full, half, and third), as well as the
local magnetic field strength jBj determined by the linear
wavelength separation of the Stark multiplet.
The third most intense feature originates from injected
fast ions which pass through the beam and halo neutrals,
recombine, and emit a D
a
photon. This FIDA emission has
received considerable interest in studies of fast-ion transport
by Alfve´n modes and turbulence.
31,32
FIDA emission is
incorporated into the spectral fit model through TRANSP
(Refs. 33 and 34) and NUBEAM (Ref. 35) production of the
fast ion distribution function. The distribution function from
NUBEAM is used as input to a three-dimensional, time-
dependent collisional-radiative modeling code FIDAsim,
detailed in Ref. 17. FIDAsim uses the complete experimental
configuration, including neutral beam source geometry and
sightlines across the vessel through the neutral beam. The
code requires equilibrium fitting code (EFIT) (Ref. 36) equi-
librium reconstruction, kinetic profiles of electron density
and temperature, ion temperature, toroidal rotation, fast ion
distribution, and impurity density. The code performs neutral
beam attenuation and emission calculations, direct charge-
exchange and emission, halo neutral pr oduction and spatial
diffusion and emission, as well as fast-ion charge-exchange
and emission. The FIDA spectral shape is used in the fitting
procedure at a fixed central wavelength, and amplitude of
the FIDA shape displayed in Fig. 2 is a free parameter. Previ-
ous work
37
on FIDA modeling indicated that the amplitude
varied much more strongly than the shape of the emission
spectrum in a wide variety of conditions; and therefore, mod-
ifications to the fast-ion distribution function will impose a
weak influence on the fit to the thermal charge exchange fea-
tures when the FIDA amplitude is un-constrained.
The final fitting step is to allow for small remaining
edge localized features which were not subtracted out per-
fectly. The contributions from the edge are highly con-
strained to be cold and emit near the rest wavelength of the
atomic transition. As disp layed in Fig. 2, the negligible in-
tensity of the edge emission gives confidence that the spec-
tral features being fit originate from deep inside the plasma
uncorrupted from the edge light.
A. Necessity of a fast-ion model
In plasma with low beam power (Fig. 2) and/or very
high density, the intensity of the FIDA contribution may be
nearly negligible, but is still included in the spectral fit to
eliminate systematic errors. However, in plasmas with high
beam power, the FIDA contribution can be significant. Dis-
played in Fig. 3 is a comparison of spectral fits wh en the
FIDA emission is omitted from the fit model, Fig. 3(a),
and when the FIDA contribution is included in the fit model
Fig. 3(b). The view displayed in Fig. 3 is of a ctr-I
p
beam,
such that the beam emission from the 210 RT beamline and
the fast-ion emission from the co-I
p
injected fast ions are on
opposite sides of the thermal Gaussian. It is clear from
Fig. 3(a) and examination of the weighted residual error that
the fit model is lacking a significant source of emission, and
the residual is unacceptably high. Comparison of the thermal
Gaussian properties between Figs. 3(a) and 3(b) indicates
that a difference in apparent ion temperature of approxi-
mately 0.1 keV and an apparent velocity difference of 8 km/s
would be incurred if the FIDA emission were neglected,
which is an unacceptably high error.
B. Qu antitative comparison of measured and modeled
emission
Due to the convoluted nature of the attenuation of the
three primary beam components on plasma profiles of elec-
tron and ion densities, and subsequent charge-exchange with
fuel ions and impurities, it is necessary to establish reasonable
agreement with all measured photoemission processes. The
injection of beam neutrals begins the process which leads to
charge-exchange emission, and hence must be modeled accu-
rately. The emission intensity from the beam neutrals is pro-
portional to the beam neutral density, I
BESðjÞ
¼ q
eff
ðv
j
Þn
eff
n
ðjÞ
b
,
FIG. 3. Comparison of spectral fitting when (a) FIDA is neglected and
(b) when FIDA is included. Neglecting the FIDA emission results in a poor
quality fit. Colors same as Fig. 2.
056107-4 Grierson et al. Phys. Plasmas 19, 056107 (2012)

Frequently asked questions

Q1. What are the contributions mentioned in the paper "Measurements of the deuterium ion toroidal rotation in the diii-d tokamak and comparison to neoclassical theory" ?

In this paper, the main ion rotation is systematically in the counter-current direction compared to carbon rotation, in significant disagreement with neoclassical theory. 

Q2. What is the subject of ongoing research efforts?

Characterization of the intrinsic rotation differences between bulk deuterium ions and carbon across operational regimes is the subject of ongoing research efforts. 

Q3. How many MW of ECH heating was used to enable H-mode access?

ECH was applied to LSN discharges in standard Ip and BT configurations (favorable rB) to enable H-mode access with approximately 0.9 MW of ECH heating. 

Q4. How is the emission of the beam incorporated into the spectral fit model?

31,32 FIDA emission is incorporated into the spectral fit model through TRANSP (Refs. 33 and 34) and NUBEAM (Ref. 35) production of the fast ion distribution function. 

Q5. What is the effect of the beam emission at high density?

At very high density, the beam can no longer penetrate effectively into the core, and the fast ion slowing down time is abbreviated considerably, such that the strength of the FIDA emission is greatly reduced. 

Q6. What is the true velocity of the co-Ip viewing system?

The true rotational velocity always lies between the two apparent velocity profiles and is closer to the ctr-Ip viewing chords due to the more perpendicular angle. 

Q7. How can the authors deduce the local properties of deuterium ion temperature?

By exploiting the large amount of information in the active Da spectrum, it is possible to deduce the local properties of thermal deuterium ion temperature, toroidal velocity and density, local beam emission intensity, beam neutral density and density fractions, fast ion emission intensity, and local magnetic field strength jBj. 

Q8. How are the corrections performed for atomic physics?

Corrections for atomic physics are performed by two separate methods; complementary views of co-current injected and counter-current injected neutral beams at matched major radii, and time-dependent collisional-radiative modeling of the atomic processes leading to thermal Da emission. 

Q9. What is the frequency of the AE activity in Figs. 15(a) and?

At 1500 ms, as qmin crosses 2.0, there is a clear burst of coherent AE activity in Figs. 15(a) and 15(b) observed as a frequency chirping, and increase in integrated cross-power. 

Q10. What is the sign of the poloidal flow in the neoclassical treatment?

It is of note that reversing the sign of the toroidal field will reverse the sign of the poloidal flow in the neoclassical treatment. 

Q11. What is the FIDA emission intensity in the plasma?

In Figs. 4(a)–4(c) (top), it can be seen that the FIDA emission intensity is peaked in the plasma core at low density, becomes flat at moderate density, and changesslope at the highest density. 

Q12. What is the subject of ongoing calculations?

The precise magnitude of the torque by fast-ion transport and required momentum diffusivity are the subject of ongoing calculations.