This article is the first design study of a combined interferometer and polarimeter on a compact, high-field, high-density, net-energy tokamak. Recent advances in superconducting technology have made possible designs for compact, high magnetic field fusion power plants, such as ARC [Sorbom et al., Fusion Eng. Des. 100, 378 (2015)], and experiments, such as SPARC [Greenwald et al., PSFC Report No. RR-18-2 (2018)]. These new designs create both challenges and opportunities for plasma diagnostics. The diagnostic proposed in this work, called InterPol, takes advantage of unique opportunities provided by high magnetic field and density to measure both line-averaged density and poloidal magnetic field with a single set of CO2 and quantum cascade lasers. These measurements will be used for fast density feedback control, constraint of density and safety factor profiles, and density fluctuation measurements. Synthetic diagnostic testing using a model machine geometry, called MQ1 (Mission Q 1), and profiles simulated with Tokamak Simulation Code indicate that InterPol will be able to measure steady state density and poloidal magnetic field, as well as fluctuations caused by toroidal Alfvén eigenmodes and other phenomena on a high-field compact tokamak.

1.
J.
Wesson
,
Tokamaks
, International Series of Monographs on Physics, 4th ed. (
Oxford University Press
,
2011
).
2.
F.
Troyon
,
R.
Gruber
,
H.
Saurenmann
,
S.
Semenzato
, and
S.
Succi
, “
MHD-limits to plasma confinement
,”
Plasma Phys. Controlled Fusion
26
(
1A
),
209
(
1984
).
3.
R. T.
Mumgaard
,
M.
Greenwald
,
J. P.
Freidberg
,
S. M.
Wolfe
,
Z. S.
Hartwig
,
D.
Brunner
,
B. N.
Sorbom
, and
D. G.
Whyte
, “
Scoping study for compact high-field superconducting net energy tokamaks
,” in
APS Division of Plasma Physics Meeting Abstracts
(
APS Meeting Abstracts
,
2016
), Vol. 2016, p. BP10.029; available at https://ui.adsabs.harvard.edu/abs/2016APS..DPPB10029M.
4.
A. R.
Polevoi
,
V. S.
Mukhovatov
,
M.
Shimada
,
S. Y.
Medvedev
,
A. A.
Ivanov
,
A. S.
Kukushkin
, and
Y.
Murakami
, “
ITER confinement and stability modelling
,” in
Proceedings of Joint Conference of ITC-12 and APFA'01: Frontiers in Plasma Confinement and Related Engineering/Plasma Science
(
2003
).
5.
B.
Sorbom
,
J.
Ball
,
T.
Palmer
,
F.
Mangiarotti
,
J.
Sierchio
,
P.
Bonoli
,
C.
Kasten
,
D.
Sutherland
,
H.
Barnard
,
C.
Haakonsen
,
J.
Goh
,
C.
Sung
, and
D.
Whyte
, “
ARC: A compact, high-field, fusion nuclear science facility and demonstration power plant with demountable magnets
,”
Fusion Eng. Des.
100
,
378
(
2015
).
6.
M.
Greenwald
,
D.
Whyte
,
P.
Bonoli
,
Z.
Hartwig
,
J.
Irby
,
B.
LaBombard
,
E.
Marmar
,
J.
Minervini
,
M.
Takayasu
,
J.
Terry
,
R.
Vieira
,
A.
White
,
S.
Wukitch
,
D.
Brunner
,
R.
Mumgaard
, and
B.
Sorbom
, “
The high-field path to practical fusion energy
,”
PSFC Report No. RR-18-2
(
2018
).
7.
R.
Mumgaard
and
SPARC Team
, “
SPARC and the high-field path
,” in
60th Annual Meeting of the APS Division of Plasma Physics
(
2018
).
8.
E.
Marmar
,
D.
Brunner
,
M.
Greenwald
,
Z.
Hartwig
,
A.
Hubbard
,
J.
Irby
,
B.
LaBombard
,
J.
Minervini
,
R.
Mumgaard
,
B.
Sorbom
,
E.
Tolman
,
D.
Whyte
,
A.
White
, and
S.
Wukitch
, “
The high field tokamak path to fusion energy: C-Mod to SPARC to ARC
,” in
60th Annual Meeting of the APS Division of Plasma Physics
(
2018
).
9.
A.
White
,
S.
Ballinger
,
A.
Creely
,
S.
Frank
,
A.
Kuang
,
B.
Linehan
,
W.
McCarthy
,
L.
Milanese
,
K.
Montes
,
T.
Mouratidis
,
J.
Picard
,
P.
Rodrigues Fernandez
,
A.
Rosentha
,
A.
Sandberg
,
F.
Sciortino
,
R.
Simpson
,
R.
Tinguely
,
E.
Tolman
,
M.
Zhou
,
B.
Sorbom
,
Z.
Hartwig
, and
J.
Irby
, “
Diagnostics for a SPARC-like, high-field, compact, net-energy tokamak
,” in
APS Division of Plasma Physics Meeting Abstracts
(
APS Meeting Abstracts
,
2018
), p. UP11.707; available at https://ui.adsabs.harvard.edu/abs/2018APS..DPPU11070W.
10.
R. A.
Tinguely
,
A.
Rosenthal
,
R.
Simpson
,
S. B.
Ballinger
,
A. J.
Creely
,
S.
Frank
,
A. Q.
Kuang
,
B. L.
Linehan
,
W.
McCarthy
,
L. M.
Milanese
,
K. J.
Montes
,
T.
Mouratidis
,
J. F.
Picard
,
P.
Rodriguez-Fernandez
,
A. J.
Sandberg
,
F.
Sciortino
,
E. A.
Tolman
,
M.
Zhou
,
B. N.
Sorbom
,
Z. S.
Hartwig
, and
A. E.
White
, “
Neutron diagnostics for the physics of a high-field, compact, Q1 tokamak
,”
Fusion Eng. Des.
143
,
212
(
2019
).
11.
I. H.
Hutchinson
,
Principles of Plasma Diagnostics
(
Cambridge University Press
,
2002
).
12.
V. V.
Mirnov
,
W. X.
Ding
,
D. L.
Brower
,
M. A. V.
Zeeland
, and
T. N.
Carlstrom
, “
Finite electron temperature effects on interferometric and polarimetric measurements in fusion plasmas
,”
Phys. Plasmas
14
(
10
),
102105
(
2007
).
13.
J. H.
Irby
,
E. S.
Marmar
,
E.
Sevillano
, and
S. M.
Wolfe
, “
Two-color interferometer system for Alcator C-MOD
,”
Rev. Sci. Instrum.
59
(
8
),
1568
(
1988
).
14.
H.
Soltwisch
, “
Current distribution measurement in a tokamak by FIR polarimetry (invited)
,”
Rev. Sci. Instrum.
57
(
8
),
1939
(
1986
).
15.
W. F.
Bergerson
,
P.
Xu
,
J. H.
Irby
,
D. L.
Brower
,
W. X.
Ding
, and
E. S.
Marmar
, “
Far-infrared polarimetry diagnostic for measurement of internal magnetic field dynamics and fluctuations in the C-Mod tokamak (invited)
,”
Rev. Sci. Instrum.
83
,
10E316
(
2012
).
16.
C. P.
Kasten
,
J. H.
Irby
,
R.
Murray
,
A. E.
White
, and
D. C.
Pace
, “
A new interferometry-based electron density fluctuation diagnostic on Alcator C-Mod
,”
Rev. Sci. Instrum.
83
,
10E301
(
2012
).
17.
S. C.
Jardin
,
N.
Pomphrey
, and
J.
Delucia
, “
Dynamic modeling of transport and positional control of tokamaks
,”
J. Comput. Phys.
66
,
481
(
1986
).
18.
B.
Coppi
and
N.
Sharky
, “
Model for particle transport in high-density plasmas
,”
Nucl. Fusion
21
,
1363
(
1981
).
19.
W. M.
Tang
, “
Microinstability-based model for anomalous thermal confinement in tokamaks
,”
Nucl. Fusion
26
,
1605
(
1986
).
20.
M. A. V.
Zeeland
,
T. N.
Carlstrom
,
D. K.
Finkenthal
,
R. L.
Boivin
,
A.
Colio
,
D.
Du
,
A.
Gattuso
,
F.
Glass
,
C. M.
Muscatello
,
R.
O'Neill
,
M.
Smiley
,
J.
Vasquez
,
M.
Watkins
,
D. L.
Brower
,
J.
Chen
,
W. X.
Ding
,
D.
Johnson
,
P.
Mauzey
,
M.
Perry
,
C.
Watts
, and
R.
Wood
, “
Tests of a two-color interferometer and polarimeter for ITER density measurements
,”
Plasma Phys. Controlled Fusion
59
(
12
),
125005
(
2017
).
21.
H. Q.
Liu
,
J. P.
Qian
,
Y. X.
Jie
,
W. X.
Ding
,
D. L.
Brower
,
Z. Y.
Zou
,
W. M.
Li
,
H.
Lian
,
S. X.
Wang
,
Y.
Yang
,
L.
Zeng
,
T.
Lan
,
Y.
Yao
,
L. Q.
Hu
,
X. D.
Zhang
, and
B. N.
Wan
, “
Initial measurements of plasma current and electron density profiles using a polarimeter/interferometer (POINT) for long pulse operation in EAST
,”
Rev. Sci. Instrum.
87
,
11D903
(
2016
).
22.
M. A.
Van Zeeland
,
R. L.
Boivin
,
D. L.
Brower
,
T. N.
Carlstrom
,
J. A.
Chavez
,
W. X.
Ding
,
R.
Feder
,
D.
Johnson
,
L.
Lin
,
R. C.
O'Neill
, and
C.
Watts
, “
Conceptual design of the tangentially viewing combined interferometer-polarimeter for ITER density measurements
,”
Rev. Sci. Instrum.
84
(
4
),
043501
(
2013
).
23.
J. P.
Freidberg
,
F. J.
Mangiarotti
, and
J.
Minervini
, “
Designing a tokamak fusion reactor–How does plasma physics fit in?
,”
Phys. Plasmas
22
(
7
),
070901
(
2015
).
24.
V. S.
Voitsenya
,
A. J.
Donné
,
A. F.
Bardamid
,
A. I.
Belyaeva
,
V. L.
Berezhnyj
,
A. A.
Galuza
,
C.
Gil
,
V. G.
Konovalov
,
M.
Lipa
,
A.
Malaquais
,
D. I.
Naidenkova
,
V. I.
Ryzhkov
,
B.
Schunke
,
S. I.
Solodovchenko
, and
A. N.
Topkov
, “
Simulation of environment effects on retroreflectors in ITER
,”
Rev. Sci. Instrum.
76
(
8
),
083502
(
2005
).
25.
D.
Van Houtte
,
K.
Okayama
, and
F.
Sagot
, “
ITER operational availability and fluence objectives
,”
Fusion Eng. Des.
86
,
680
683
(
2011
).
26.
T. N.
Carlstrom
,
D. R.
Ahlgren
, and
J.
Crosbie
, “
Real–time, vibration–compensated CO2 interferometer operation on the DIII–D tokamak
,”
Rev. Sci. Instrum.
59
(
7
),
1063
(
1988
).
27.
P.
Innocente
,
S.
Martini
,
A.
Canton
, and
L.
Tasinato
, “
Upgrade of the RFX CO2 interferometer using in-vessel optics for extended edge resolution
,”
Rev. Sci. Instrum.
68
(
1
),
694
(
1997
).
28.
Y.
Kawano
,
A.
Nagashima
,
T.
Hatae
, and
S.
Gunji
, “
Dual CO2 laser interferometer with a wavelength combination of 10.6 and 9.27 m for electron density measurement on large tokamaks
,”
Rev. Sci. Instrum.
67
(
4
),
1520
(
1996
).
29.
D. R.
Baker
and
S.
Lee
, “
Dual laser interferometer for plasma density measurements on large tokamaks
,”
Rev. Sci. Instrum.
49
(
7
),
919
(
1978
).
30.
A. J. H.
Donne
,
A.
Costley
,
R.
Barnsley
,
H.
Bindslev
,
R.
Boivin
,
G.
Conway
,
R.
Fisher
,
R.
Giannella
,
H.
Hartfuss
,
M.
von Hellermann
,
E.
Hodgson
,
L.
Ingesson
,
K.
Itami
,
D.
Johnson
,
Y.
Kawano
,
T.
Kondoh
,
A.
Krasilnikov
,
Y.
Kusama
,
A.
Litnovsky
,
P.
Lotte
,
P.
Nielsen
,
T.
Nishitani
,
F.
Orsitto
,
B.
Peterson
,
G.
Razdobarin
,
J.
Sanchez
,
M.
Sasao
,
T.
Sugie
,
G.
Vayakis
,
V.
Voitsenya
,
K.
Vukolov
,
C.
Walker
,
K.
Young
, and ITPA
Topical Group on Diagnostics
, “
Chapter 7: Diagnostics
,”
Nucl. Fusion
47
,
S337
(
2007
).
31.
K.
Kawahata
,
A.
Ejiri
,
K.
Tanaka
,
Y.
Ito
, and
S.
Okajima
, “
Design and construction of a far infrared laser interferometer for the LHD
,”
Fusion Eng. Des.
34–35
,
393
(
1997
).
32.
A.
Mlynek
,
G.
Schramm
,
H.
Eixenberger
,
G.
Sips
,
K.
McCormick
,
M.
Zilker
,
K.
Behler
,
J.
Eheberg
, and ASDEX
Upgrade Team
, “
Design of a digital multiradian phase detector and its application in fusion plasma interferometry
,”
Rev. Sci. Instrum.
81
,
033507
(
2010
).
33.
A.
Mlynek
,
L.
Casali
,
O.
Ford
,
H.
Eixenberger
, and
ASDEX Upgrade Team
, “
Fringe jump analysis and implementation of polarimetry on the ASDEX Upgrade DCN interferometer
,”
Rev. Sci. Instrum.
85
,
11D408
(
2014
).
34.
G.
Braithwaite
,
N.
Gottardi
,
G.
Magyar
,
J. R. J.
O'Rourke
, and
D.
Veron
, “
JET polari-interferometer
,”
Rev. Sci. Instrum.
60
,
2825
(
1989
).
35.
K.
Kawahata
,
T.
Akiyama
,
K.
Tanaka
,
S.
Okajima
, and
K.
Nakayama
, “
Recent progress in two-color laser diagnostics
,”
J. Phys.
227
,
012022
(
2010
).
36.
K.
Kawahata
,
T.
Akiyama
,
K.
Tanaka
,
K.
Nakayama
, and
S.
Okajima
, “
Progress in development of two color laser diagnostics for the ITER poloidal polarimeter
,”
J. Instrum.
7
(
2
),
C02002
(
2012
).
37.
J.
Chen
,
G.
Zhuang
,
Q.
Li
,
Y.
Liu
,
L.
Gao
,
Y. N.
Zhou
,
X.
Jian
,
C. Y.
Xiong
,
Z. J.
Wang
,
D. L.
Brower
, and
W. X.
Ding
, “
High resolution polarimeter-interferometer system for fast equilibrium dynamics and MHD instability studies on joint-TEXT tokamak (invited)
,”
Rev. Sci. Instrum.
85
,
11D303
(
2014
).
38.
M. A.
Van Zeeland
,
R. L.
Boivin
,
T. N.
Carlstrom
, and
T. M.
Deterly
, “
CO2 laser polarimeter for Faraday rotation measurements in the DIII-D tokamak
,”
Rev. Sci. Instrum.
79
,
10E719
(
2008
).
39.
C. P.
Kasten
,
A. E.
White
, and
J. H.
Irby
, “
A new fast two-color interferometer at Alcator C-Mod for turbulence measurements and comparison with phase contrast imaging
,”
Phys. Plasmas
21
(
4
),
042305
(
2014
).
40.
W. W.
Heidbrink
, “
Basic physics of Alfvén instabilities driven by energetic particles in toroidally confined plasmas
,”
Phys. Plasmas
15
(
5
),
055501
(
2008
).
You do not currently have access to this content.