3D equilibria with an anisotropic pressure component in the large helical device are analyzed with respect to their magnetic axis locations. The anisotropic extension of the 3D equilibrium solver variational moments equilibrium code, anisotropic neumann inverse moments equilibrium code, is used to compute fixed-boundary plasma equilibria based on a bi-Maxwellian distribution function describing the anisotropic particles. Different heating scenarios are assessed by means of parallel and perpendicular pressure anisotropies with different radial anisotropic pressure profiles imposed. A theoretical predicted scaling of the magnetic axis location with the auxiliary parameter βeq as predicted for classical stellarators and heliotrons by Hitchon [Nucl. Fusion 23, 383 (1983)] is found to be applicable to the large helical device in the case of a flat hot-particle profile for parallel or weak perpendicular dominated anisotropies with β/β2. For strong perpendicular or non-flat hot-particle profiles, a deviation from the predicted scaling of the magnetic axis location is found. Whereas center-peaked profiles show a stronger shift of the magnetic axis, edge-peaked profiles show no significant change of its radial location. High critical magnetic fields are identified as a necessary condition for strong perpendicular anisotropies. The observed deviations are ascribed to the magnetic field structure and negative pressure gradients. The invalidity of the theoretical predictions in the case of certain configurations is found to be caused by higher-order terms in the pressure components, which are not accounted for by the ordering on which the theory is based.

1.
K.
Watanabe
,
S.
Sakakibara
,
Y.
Narushima
,
H.
Funaba
,
K.
Narihara
,
K.
Tanaka
,
T.
Yamaguchi
,
K.
Toi
,
S.
Ohdachi
,
O.
Kaneko
,
H.
Yamada
,
Y.
Suzuki
,
W.
Cooper
,
S.
Murakami
,
N.
Nakajima
,
I.
Yamada
,
K.
Kawahata
,
T.
Tokuzawa
,
A.
Komori
, and
LHD Experimental Group
,
Nucl. Fusion
45
,
1247
(
2005
).
2.
T.
Yamaguchi
,
K.
Watanabe
,
S.
Sakakibara
,
Y.
Narushima
,
K.
Narihara
,
T.
Tokuzawa
,
K.
Tanaka
,
I.
Yamada
,
M.
Osakabe
,
H.
Yamada
,
K.
Kawahata
,
K.
Yamazaki
, and
LHD Experimental Group
,
Nucl. Fusion
45
,
L33
(
2005
).
3.
K.
Watanabe
,
Y.
Suzuki
,
S.
Sakakibara
,
T.
Yamaguchi
,
Y.
Narushima
,
Y.
Nakamura
,
K.
Ida
,
N.
Nakajima
,
H.
Yamada
, and
LHD Experimental Group
,
Fusion Sci. Technol.
58
,
160
(
2010
).
4.
S.
Hirshman
and
O.
Betancourt
,
J. Comput. Phys.
96
,
99
(
1991
).
5.
W. A.
Cooper
,
S. P.
Hirshman
,
P.
Merkel
,
J. P.
Graves
,
J.
Kisslinger
,
H. F.
Wobig
,
Y.
Narushima
,
S.
Okamura
, and
K. Y.
Watanabe
,
Comput. Phys. Commun.
180
,
1524
(
2009
).
6.
W.
Cooper
,
J.
Graves
,
S.
Hirshman
,
T.
Yamaguchi
,
Y.
Narushima
,
S.
Okamura
,
S.
Sakakibara
,
C.
Suzuki
,
K.
Watanabe
,
H.
Yamada
, and
K.
Yamazaki
,
Nucl. Fusion
46
,
683
(
2006
).
7.
W.
Cooper
,
S.
Hirshman
,
S.
Merazzi
, and
R.
Gruber
,
Comput. Phys. Commun.
72
,
1
(
1992
).
8.
W.
Cooper
,
S.
Hirshman
,
T.
Yamaguchi
,
Y.
Narushima
,
S.
Okamura
,
S.
Sakakibara
,
C.
Suzuki
,
K.
Watanabe
,
H.
Yamada
, and
K.
Yamazaki
,
Plasma Phys. Controlled Fusion
47
,
561
(
2005
).
9.
Y.
Asahi
,
Y.
Suzuki
,
K.
Watanabe
, and
W. A.
Cooper
,
Plasma Fusion Res.
6
,
2403123
(
2011
).
10.
J.
Graves
,
W.
Cooper
,
S.
Coda
,
L.-G.
Eriksson
,
T.
Johnson
, and
J.-E. Contributors
, “Modelling ICCD Experiments for Sawtooth Control in JET” https://aip.scitation.org/doi/pdf/10.1063/1.2404569 (
American Institute of Physics
,
2006
), p.
350
.
11.
W.
Cooper
,
Y.
Asahi
,
Y.
Narushima
,
Y.
Suzuki
,
K.
Watanabe
,
J.
Graves
, and
M. Y.
Isaev
,
Phys. Plasmas
19
,
102503
(
2012
).
12.
13.
W.
Hitchon
and
P.
Fielding
,
Nucl. Fusion
21
,
775
(
1981
).
14.
J.
Greene
and
J.
Johnson
,
Phys. Fluids
4
,
875
(
1961
).
15.
G.
Chew
,
M.
Goldberger
, and
F.
Low
,
Proc. R. Soc. London, Ser. A
236
,
1204
(
1956
).
16.
V.
Pustovitov
,
Plasma Phys. Controlled Fusion
52
,
065001
(
2010
).
17.
P.
Fielding
and
W.
Hitchon
,
J. Plasma Phys.
24
,
453
(
1980
).
18.
19.
S.
Hirshman
,
W.
van Rij
, and
P.
Merkel
,
Comput. Phys. Commun.
43
,
143
(
1986
).
20.
K.
McClements
,
R.
Dendy
,
R.
Hastie
, and
T.
Martin
,
Phys. Plasmas
3
,
2994
(
1996
).
21.
W.
Cooper
,
J.
Graves
,
M.
Jucker
,
K.
Watanabe
,
Y.
Narushima
, and
T.
Yamaguchi
,
Plasma Phys. Controlled Fusion
49
,
1177
(
2007
).
22.
K.
Ogawa
,
M.
Isobe
,
H.
Kawase
,
T.
Nishitani
,
R.
Seki
,
M.
Osakabe
, and
L. E. Group
,
Plasma Phys. Controlled Fusion
60
,
044005
(
2018
).
You do not currently have access to this content.