Diverse disruption mitigation strategies based on massive material injection have been developed in recent decades, aiming to uniformly deplete the thermal energy stored within plasmas during the thermal quench (TQ) while simultaneously elevating electron density to facilitate runaway electron suppression. Irrespective of the detailed dynamics of the material delivery scheme, deposition location and subsequent density mixing are pivotal in achieving highly efficient mitigation, however, which are markedly influenced by magnetohydrodynamic (MHD) activities. In order to assess the influence of MHD-induced transport on disruption mitigation, a simulation of TQ triggered by pure deuterium (D) deposition is conducted using a three-dimensional (3D) nonlinear reduced MHD code, JOREK. Steady density sources (the deposition rate of 1024 D atoms per second is greater than in real experiments) are introduced at various locations to explore the dynamics. The findings distinctly reveal two types of TQ processes, contingent on locations of deposition (LoD) of the neutral D source. Evidently, the results underscore the effectiveness of proper density mixing and moderated MHD in disruption mitigation. Nonlinear mode coupling emerges as a significant factor in shaping the final outcomes of TQ. Specifically, the 5/2 mode contributes to edge collapse, whereas the 3/2 mode is instrumental in core collapse. Additionally, the investigation indicates that the rise in core density is contingent on LoD, exhibiting threshold behavior. This threshold is observed within the q = 2/1 surface of equilibria, and a rapid increase in core density is witnessed when the density source crosses this threshold. The outcomes point toward the important role of E × B convection due to the 1/1 mode evolution in the process.

1.
T. C.
Hender
,
J. C.
Wesley
,
J.
Bialek
,
A.
Bondeson
,
A. H.
Boozer
,
R. J.
Buttery
,
A.
Garofalo
,
T. P.
Goodman
,
R. S.
Granetz
,
Y.
Gribov
et al, “
ITER physics basis chapter 3: MHD stability, operational limits and disruptions
,”
Nucl. Fusion
47
,
S128
S202
(
2007
).
2.
ITER Physics Expert Group on Disruptions, Plasma Control, and MHD
, “
Chapter 3: MHD stability, operational limits and disruptions
,”
Nucl. Fusion
39
,
2251
(
1999
).
3.
E. M.
Hollmann
,
P. B.
Aleynikov
,
T.
Fülöp
,
D. A.
Humphreys
,
V. A.
Izzo
,
M.
Lehnen
,
V. E.
Lukash
,
G.
Papp
,
G.
Pautasso
,
F.
Saint-Laurent
et al, “
Status of research toward the ITER disruption mitigation system
,”
Phys. Plasmas
22
,
021802
(
2015
).
4.
V.
Riccardo
and
JET EFDA Contributors,
Disruptions and disruption mitigation
,”
Plasma Phys. Controlled Fusion
45
,
A269
(
2003
).
5.
V.
Riccardo
,
A.
Loarte
, and
JET EFDA Contributors
, “
Timescale and magnitude of plasma thermal energy loss before and during disruptions in JET
,”
Nucl. Fusion
45
,
1427
(
2005
).
6.
D.
Hu
,
E.
Nardon
,
G. T. A.
Huijsmans
,
M.
Lehnen
,
D. C.
van Vugt
, and
JET Contributors
, “
JOREK simulations of shattered pellet injection with high Z impurities
,” in
Proceedings of the 45th EPS Conference on Plasma Physics
(
EPS
, Prague, Czech Republic, 2018), p.
P4.1043
.
7.
R.
Yoshino
,
S.
Tokuda
, and
Y.
Kawano
, “
Generation and termination of runaway electronsat major disruptions in JT-60U
,”
Nucl. Fusion
39
,
151
(
1999
).
8.
T. E.
Evans
,
A. G.
Kellman
,
D. A.
Humphreys
,
M. J.
Schaffer
,
P. L.
Taylor
,
D. G.
Whyte
,
T. C.
Jernigan
,
A. W.
Hyatt
, and
R. L.
Lee
, “
Measurements of non-axisymmetric halo currents with and without ‘killer’ pellets during disruptions in the DIII-D tokamak
,”
J. Nucl. Mater.
241
,
606
(
1997
).
9.
D. G.
Whyte
,
T. E.
Evans
,
A. W.
Hyatt
,
T. C.
Jernigan
,
R. L.
Lee
,
A. G.
Kellman
,
P. B.
Parks
,
R.
Stockdale
, and
P. L.
Taylor
, “
Rapid inward impurity transport during impurity pellet injection on the DIII-D tokamak
,”
Phys. Rev. Lett.
81
,
4392
(
1998
).
10.
E.
Nardon
,
A.
Fil1
,
M.
Hoelzl
,
G.
Huijsmans
, and
JET Contributors
, “
Progress in understanding disruptions triggered by massive gas injection via 3D non-linear MHD modelling with JOREK
,”
Plasma Phys. Controlled Fusion
59
,
014006
(
2017
).
11.
A.
Fil
,
E.
Nardon
,
M.
Hoelzl
,
G. T. A.
Huijsmans
,
F.
Orain
,
M.
Becoulet
,
P.
Beyer
,
G.
Dif-Pradalier
,
R.
Guirlet
,
H. R.
Koslowski
et al, “
Three-dimensional non-linear magnetohydrodynamic modeling of massive gas injection triggered disruptions in JET
,”
Phys. Plasmas
22
,
062509
(
2015
).
12.
V. A.
Izzo
, “
A numerical investigation of the effects of impurity penetration depth on disruption mitigation by massive high-pressure gas jet
,”
Nucl. Fusion
46
,
541
547
(
2006
).
13.
M.
Lehnen
,
S. N.
Gerasimov
,
S.
Jachmich
,
H. R.
Koslowski
,
U.
Kruezi
,
G. F.
Matthews
,
J.
Mlynar
,
C.
Reux
,
P. C.
de Vries
, and
JET Contributors
, “
Radiation asymmetries during the thermal quench of massive gas injection disruptions in JET
,”
Nucl. Fusion
55
,
123027
(
2015
).
14.
D. G.
Whyte
,
T. C.
Jernigan
,
D. A.
Humphreys
,
A. W.
Hyatt
,
C. J.
Lasnier
,
P. B.
Parks
,
T. E.
Evans
,
M. N.
Rosenbluth
,
P. L.
Taylor
,
A. G.
Kellman
et al, “
Mitigation of tokamak disruptions using high-pressure gas injection
,”
Phys. Rev. Lett.
89
,
055001
(
2002
).
15.
N.
Commaux
,
D.
Shiraki
,
L. R.
Baylor
,
E. M.
Hollmann
,
N. W.
Eidietis
,
C. J.
Lasnier
,
R. A.
Moyer
,
T. C.
Jernigan
,
S. J.
Meitner
,
S. K.
Combs
et al, “
First demonstration of rapid shutdown using neon shattered pellet injection for thermal quench mitigation on DIII-D
,”
Nucl. Fusion
56
,
046007
(
2016
).
16.
V. A.
Izzo
, “
Interpretive MHD modeling of dispersive shell pellet injection for rapid shutdown in tokamaks
,”
Nucl. Fusion
60
,
066023
(
2020
).
17.
E. M.
Hollmann
,
P. B.
Parks
,
D.
Shiraki
,
N.
Alexander
,
N. W.
Eidietis
,
C. J.
Lasnier
, and
R. A.
Moyer
, “
Demonstration of tokamak discharge shutdown with shell pellet payload impurity dispersal
,”
Phys. Rev. Lett.
122
,
065001
(
2019
).
18.
P. B.
Parks
,
M. N.
Rosenbluth
,
S. V.
Putvinskij
, and
T. E.
Evans
, “
High-velocity liquid jet injection into tokamak plasmas for disruption mitigation
,”
Fusion Technol.
35
,
267
(
1999
).
19.
M.
Hoelzl
,
G. T. A.
Huijsmans
,
S. J. P.
Pamela
,
M.
Bécoulet
,
E.
Nardon
,
F. J.
Artola
,
B.
Nkonga
,
C. V.
Atanasiu
,
V.
Bandaru
,
A.
Bhole
et al, “
The JOREK non-linear extended MHD code and applications to large-scale instabilities and their control in magnetically confined fusion plasmas
,”
Nucl. Fusion
61
,
065001
(
2021
).
20.
Y. P.
Zhang
,
Y.
Liu
,
G. L.
Yuan
,
M.
Isobe
,
Z. Y.
Chen
,
J.
Cheng
,
X. Q.
Ji
,
X. M.
Song
,
J. W.
Yang
,
X. Y.
Song
et al, “
Observation of the generation and evolution of long-lived runaway electron beams during major disruptions in the HuanLiuqi-2A tokamak
,”
Phys. Plasmas
19
,
032510
(
2012
).
21.
D. A.
Gates
and
L.
Delgado-Aparicio
, “
Origin of tokamak density limit scalings
,”
Phys. Rev. Lett.
108
,
165004
(
2012
).
22.
D.
Biskamp
,
Nonlinear Magnetohydrodynamics
(
Cambridge University Press
,
Cambridge
,
1993
).
23.
A.
Bondeson
,
R. D.
Parker
,
M.
Hugon
, and
P.
Smeulders
, “
MHD modeling of density limit disruptions in tokamaks
,”
Nucl. Fusion
31
,
1695
(
1991
).
24.
A. B.
Rechester
and
M. N.
Rosenbluth
, “
Electron heat transport in a tokamak with destroyed magnetic surfaces
,”
Phys. Rev. Lett.
40
(
1
),
38
(
1978
).
25.
S.
Mordijck
,
E. J.
Doyle
,
G. R.
Mckee
,
R. A.
Moyer
,
T. L.
Rhodes
,
L.
Zeng
,
N.
Commaux
,
M. E.
Fenstermacher
,
K. W.
Gentle
, and
H.
Reimerdes
, “
Changes in particle transport as a result of resonant magnetic perturbations in DIII-D
,”
Phys. Plasmas
19
,
056503
(
2012
).
26.
A.
Matsuyama
,
R.
Sakamoto
,
R.
Yasuhara
,
H.
Funaba
,
H.
Uehara
,
I.
Yamada
,
T.
Kawate
, and
M.
Goto
, “
Enhanced material assimilation in a toroidal plasma using mixed H2 + Ne pellet injection and implications to ITER
,”
Phys. Rev. Lett.
129
,
255001
(
2022
).
27.
N.
Commaux
,
B.
Pégourié
,
L. R.
Baylor
,
F.
Köchl
,
P. B.
Parks
,
T. C.
Jernigan
,
A.
Géraud
, and
H.
Nehme
, “
Influence of the low order rational q surfaces on the pellet deposition profile
,”
Nucl. Fusion
50
,
025011
(
2010
).
28.
H. W.
Müller
,
R.
Dux
,
M.
Kaufmann
,
P. T.
Lang
,
A.
Lorenz
,
M.
Maraschek
,
V.
Mertens
,
J.
Neuhauser
, and
ASDEX Upgrade Team
, “
High β plasmoid formation, drift and striations during pellet ablation in ASDEX Upgrade
,”
Nucl. Fusion
42
,
301
309
(
2002
).
29.
J. P.
Graves
,
D.
Zullino
,
D.
Brunetti
,
S.
Lanthaler
, and
C.
Wahlberg
, “
Reduced models for parallel magnetic field fluctuations and their impact on pressure gradient driven MHD instabilities in axisymmetric toroidal plasmas
,”
Plasma Phys. Controlled Fusion
61
,
104003
(
2019
).
You do not currently have access to this content.