While nuclear fusion ignition has been achieved at the National Ignition Facility in inertial confinement fusion (ICF) experiments, obtaining higher gain and more efficient burn is still desired. In that regard, increasing the compression of the fuel is an important factor. In recent indirect-drive capsule implosions, the SQ-n campaign is testing the hypothesis that reducing the hydrodynamic growth of perturbations is key to achieving higher compression of high-density carbon based-ablators for ICF. SQ-n uses a design at lower adiabat with a ramped foot laser pulse shape to minimize early-time hydrodynamic instability growth, predicted to be reduced by a factor of 10, and an optimized ablator dopant distribution. Subsets of experiments were conducted within the SQ-n campaign to study the implosion symmetry, laser backscatter, stability, and compression. Only the latter two will be reviewed here. Shock timing experiments using the velocity interferometer system for any reflector diagnostic enabled the development of a gently accelerating shock velocity. The ice–ablator interface acceleration, important for managing the Richtmyer–Meshkov phase growth, was observed with refraction enhanced radiography and the ablation front growth was measured using radiography of pre-imposed modulations. Finally, layered tritium-hydrogen-deuterium (∼75% H, ∼25% T, ∼2–10% D) and deuterium–tritium implosions demonstrate that between 15% ± 3% and 30% ± 6% improved compression has been achieved.

1.
G. H.
Miller
,
E. I.
Moses
, and
C. R.
Wuest
, “
The National Ignition Facility: Enabling fusion ignition for the 21st century
,”
Nucl. Fusion
44
,
S228
(
2004
).
2.
J.
Lindl
, “
Development of the indirect-drive approach to inertial confinement fusion and the target physics basis for ignition and gain
,”
Phys. Plasmas
2
(
11
),
3933
(
1995
).
3.
S.
Atzeni
and
J.
Meyer-ter-Vehn
,
The Physics of Inertial Fusion: Beam Plasma Interaction, Hydrodynamics, Hot Dense Matter
(
Oxford University Press
,
Oxford
,
2004
).
4.
E. I.
Moses
,
J.
Atherton
,
L.
Lagin
,
D.
Larson
,
C.
Keane
,
B.
MacGowan
,
R.
Patterson
,
M.
Spaeth
,
B.
Van Wonterghem
,
P.
Wegner
et al, “
The National Ignition Facility: Transition to a user facility
,”
J. Phys.: Conf. Ser.
688
,
012073
(
2016
).
5.
J. D.
Lindl
,
O. L.
Landen
,
J.
Edwards
,
E. I.
Moses
,
J.
Adams
,
P. A.
Amendt
,
N.
Antipa
,
P. A.
Arnold
,
R. C.
Ashabranner
,
L. J.
Atherton
et al, “
Review of the National Ignition Campaign 2009–2012
,”
Phys. Plasmas
21
,
020501
(
2014
).
6.
L.
Berzak Hopkins
,
S.
LePape
,
L.
Divol
,
A.
Pak
,
E.
Dewald
,
D. D.
Ho
,
N.
Meezan
,
S.
Bhandarkar
,
L. R.
Benedetti
, and
T.
Bunn
,
Plasma Phys. Controlled Fusion
61
,
014023
(
2019
).
7.
A. L.
Kritcher
,
C. V.
Young
,
H. F.
Robey
,
C. R.
Weber
,
A. B.
Zylstra
,
O. A.
Hurricane
,
D. A.
Callahan
,
J. E.
Ralph
,
J. S.
Ross
,
K. L.
Baker
et al, “
Design of inertial fusion implosions reaching the burning plasma regime
,”
Nat. Phys.
18
,
251
258
(
2022
).
8.
A. B.
Zylstra
,
O. A.
Hurricane
,
D. A.
Callahan
,
A. L.
Kritcher
,
J. E.
Ralph
,
H. F.
Robey
,
J. S.
Ross
,
C. V.
Young
,
K. L.
Baker
,
D. T.
Casey
et al, “
Burning plasma achieved in inertial fusion
,”
Nature
601
,
542
(
2022
).
9.
H.
Abu-Shawareb
,
R.
Acree
,
P.
Adams
,
J.
Adams
,
B.
Addis
,
R.
Aden
,
2P.
Adrian
,
B. B.
Afeyan
,
M.
Aggleton
,
L.
Aghaian
et al,
Phys. Rev. Lett.
129
,
075001
(
2022
).
10.
N. B.
Meezan
,
L. F.
Berzak Hopkins
,
S.
Le Pape
,
L.
Divol
,
A. J.
MacKinnon
,
T.
Döppner
,
D. D.
Ho
,
O. S.
Jones
,
S. F.
Khan
,
T.
Ma
et al, “
Cryogenic tritium-hydrogen deuterium and deuterium-tritium layer implosions with high density carbon ablators in near-vacuum hohlraums
,”
Phys. Plasmas
22
,
062703
(
2015
).
11.
D. S.
Clark
,
C. R.
Weber
,
J. L.
Milovich
,
A. E.
Pak
,
D. T.
Casey
,
B. A.
Hammel
,
D. D.
Ho
,
O. S.
Jones
,
J. M.
Koning
,
A. L.
Kritcher
et al, “
Three-dimensional modeling and hydrodynamic scaling of national ignition facility implosions
,”
Phys. Plasmas
26
,
050601
(
2019
).
12.
P. K.
Patel
,
P. T.
Springer
,
C. R.
Weber
,
L. C.
Jarrott
,
O. A.
Hurricane
,
B.
Bachmann
,
K. L.
Baker
,
L. F.
Berzak Hopkins
,
D. A.
Callahan
,
D. T.
Casey
et al, “
Hotspot conditions achieved in inertial confinement fusion experiments on the National Ignition Facility
,”
Phys. Plasmas
27
,
050901
(
2020
).
13.
L.
Divol
,
A.
Pak
,
L. F.
Berzak Hopkins
,
S. L.
Pape
,
N. B.
Meezan
,
E. L.
Dewald
,
D. D.-M.
Ho
,
S. F.
Khan
,
A. J.
Mackinnon
,
J. S.
Ross
et al, “
Symmetry control of an indirectly driven high-density-carbon implosion at high convergence and high velocity
,”
Phys. Plasmas
24
,
056309
(
2017
).
14.
S.
Le Pape
,
L.
Divol
,
L.
Berzak Hopkins
,
A.
Mackinnon
,
N. B.
Meezan
,
D.
Casey
,
J.
Frenje
,
H.
Herrmann
,
J.
McNaney
,
T.
Ma
et al, “
Observation of a reflected shock in an indirectly driven spherical implosion at the National Ignition Facility
,”
Phys. Rev. Lett.
112
,
225002
(
2014
).
15.
R. D.
Richtmyer
, “
Taylor instability in shock acceleration of compressible fluids
,”
Commun. Pure Appl. Math.
13
(
2
),
297
319
(
1960
).
16.
E. E.
Meshkov
, “
Instability of a shock wave accelerated interface between two gases
,”
Fluid Dyn.
4
,
101
(
1970
).
17.
G.
Dimonte
and
B.
Remington
, “
Richtmyer-Meshkov experiments on the Nova laser at high compression
,”
Phys. Rev. Lett.
70
,
1806
(
1993
).
18.
Lord
Rayleigh
, “
Investigation of the character of the equilibrium of an incompressible heavy fluid of variable density
,”
Proc. London Math. Soc.
s1–s14
,
170
(
1882
).
19.
G.
Taylor
, “
The instability of liquid surfaces when accelerated in a direction perpendicular to their planes. I
,”
Proc. R. Soc. London, Ser. A
201
,
192
(
1950
).
20.
K. A.
Flippo
,
F. W.
Doss
,
J. L.
Kline
,
E. C.
Merritt
,
D.
Capelli
,
T.
Cardenas
,
B.
DeVolder
,
F.
Fierro
,
C. M.
Huntington
,
L.
Kot
et al, “
Late-time mixing sensitivity to initial broadband surface roughness in high-energy-density shear layers
,”
Phys. Rev. Lett.
117
,
225001
(
2016
).
21.
F. W.
Doss
,
J. L.
Kline
,
K. A.
Flippo
,
T. S.
Perry
,
B. G.
DeVolder
,
I.
Tregillis
,
E. N.
Loomis
,
E. C.
Merritt
,
T. J.
Murphy
,
L.
Welser-Sherrill
et al, “
The shock/shear platform for planar radiation-hydrodynamics experiments on the National Ignition Facility
,”
Phys. Plasmas
22
,
056303
(
2015
).
22.
N.
Metzler
,
A. L.
Velikovich
, and
J. H.
Gardner
,
Phys. Plasmas
6
,
3283
(
1999
).
23.
D. S.
Clark
,
D. T.
Casey
,
C.
Weber
,
O. S.
Jones
,
K.
Baker
,
E. L.
Dewald
,
L.
Divol
,
A.
Do
,
A. L.
Kritcher
,
O. L.
Landen
et al, “
Exploring implosion designs for increased compression on the National Ignition Facility using high density carbon ablators
,”
Phys. Plasmas
29
,
052710
(
2022
).
24.
A.
Do
,
C. R.
Weber
,
E. L.
Dewald
,
D. T.
Casey
,
D. S.
Clark
,
S. F.
Khan
,
O. L.
Landen
,
A. G.
MacPhee
, and
V. A.
Smalyuk
,
Phys. Rev. Lett.
129
,
215003
(
2022
).
25.
R.
Tommasini
,
D. T.
Casey
,
D.
Clark
,
A.
Do
,
K. L.
Baker
,
O. L.
Landen
,
V. A.
Smalyuk
,
C.
Weber
,
B.
Bachmann
,
E.
Hartouni
et al,
Phys. Rev. E
(to be published).
26.
C. R.
Weber
,
D. S.
Clark
,
D. T.
Casey
,
G. N.
Hall
,
O.
Jones
,
O.
Landen
,
A. E.
Pak
, and
V. A.
Smalyuk
, “
Reduced mixing in inertial confinement fusion with early-time interface acceleration
,”
Phys. Rev. E
108
,
L023202
(
2023
).
27.
H. F.
Robey
,
P. M.
Celliers
,
J. L.
Kline
,
A. J.
Mackinnon
,
T. R.
Boehly
,
O. L.
Landen
,
J. H.
Eggert
,
D.
Hicks
,
S.
Le Pape
,
D. R.
Farley
et al,
Phys. Rev. Lett.
108
,
215004
(
2012
).
28.
P. M.
Celliers
and
M.
Millot
, “
Imaging velocity interferometer system for any reflector (VISAR) diagnostics for high energy density sciences
,”
Rev. Sci. Instrum.
94
(
1
),
011101
(
2023
).
29.
J. A.
Koch
,
O. L.
Landen
,
B. J.
Kozioziemski
,
N.
Izumi
,
E. L.
Dewald
,
J. D.
Salmonson
, and
B. A.
Hammel
, “
Refraction-enhanced x-ray radiography for inertial confinement fusion and laser-produced plasma applications
,”
J. Appl. Phys.
105
,
113112
(
2009
).
30.
K.
Baker
,
C.
Thomas
,
D.
Casey
,
S.
Khan
,
B.
Spears
,
R.
Nora
,
T.
Woods
,
J.
Milovich
,
R.
Berger
,
D.
Strozzi
et al,
Phys. Rev. Lett.
121
,
135001
(
2018
).
31.
D.
Casey
,
C.
Thomas
,
K.
Baker
,
B.
Spears
,
M.
Hohenberger
,
S.
Khan
,
R.
Nora
,
C.
Weber
,
D.
Woods
, and
O.
Hurricane
,
Phys. Plasmas
25
,
056308
(
2018
).
32.
M. M.
Marinak
,
G. D.
Kerbel
,
N. A.
Gentile
,
O.
Jones
,
D.
Munro
,
S.
Pollaine
,
T. R.
Dittrich
, and
S. W.
Haan
, “
Three-dimensional HYDRA simulations of National Ignition Facility targets
,”
Phys. Plasmas
8
(
5
),
2275
(
2001
).
33.
S.
Davidovits
,
C. R.
Weber
, and
D. S.
Clark
,
Phys. Plasmas
29
,
112708
(
2022
).
34.
J. A.
Koch
,
O. L.
Landen
,
L. J.
Suter
,
L. P.
Masse
,
D. S.
Clark
,
J. S.
Ross
,
A. J.
Mackinnon
,
N. B.
Meezan
,
C. A.
Thomas
, and
Y.
Ping
, “
Refraction-enhanced backlit imaging of axially symmetric inertial confinement fusion plasmas
,”
Appl. Opt.
52
,
3538
(
2013
).
35.
E.
Dewald
,
O.
Landen
,
D.
Ho
,
L.
Berzak Hopkins
,
Y.
Ping
,
L.
Masse
,
D.
Thorn
,
J.
Kroll
, and
A.
Nikroo
, “
Direct observation of density gradients in ICF capsule implosions via streaked refraction enhanced radiography (RER)
,”
High Energy Density Phys.
36
,
100795
(
2020
).
36.
A.
Kar
,
T. R.
Boehly
,
P. B.
Radha
,
D. H.
Edgell
,
S. X.
Hu
,
P. M.
Nilson
,
A.
Shvydky
,
W.
Theobald
,
D.
Cao
,
K. S.
Anderson
et al, “
Simulated refraction-enhanced x-ray radiography of laser-driven shocks
,”
Phys. Plasmas
26
,
032705
(
2019
).
37.
E. L.
Dewald
,
R.
Tommasini
,
A.
Mackinnon
,
A.
MacPhee
,
N.
Meezan
,
R.
Olson
,
D.
Hicks
,
S.
LePape
,
N.
Izumi
,
K.
Fournier
et al, “
Capsule ablator inflight performance measurements via streaked radiography of ICF implosions on the NIF
,” in
8th International Conference on Inertial Fusion Sciences and Applications
,
2016
.
38.
C.
Weber
,
T.
Doppner
,
D.
Casey
,
T.
Bunn
,
L.
Carlson
,
R.
Dylla-Spears
,
B.
Kozioziemski
,
A. G.
MacPhee
,
J.
Sater
,
A.
Nikroo
et al,
J. Phys.: Conf. Ser.
717
,
012057
(
2016
).
39.
V. A.
Smalyuk
,
S. X.
Hu
,
J. D.
Hager
,
J. A.
Delettrez
,
D. D.
Meyerhofer
,
T. C.
Sangster
, and
D.
Shvarts
,
Phys. Rev. Lett.
103
,
105001
(
2009
).
40.
E. L.
Dewald
,
R.
Tommasini
,
N. B.
Meezan
,
O. L.
Landen
,
S.
Khan
,
R.
Rygg
,
J.
Field
,
A. S.
Moore
,
D.
Sayre
,
A. J.
MacKinnon
et al,
Phys. Plasmas
25
(
9
),
092702
(
2018
).
41.
J. A.
Frenje
,
R.
Bionta
,
E. J.
Bond
,
J. A.
Caggiano
,
D. T.
Casey
,
C.
Cerjan
,
J.
Edwards
,
M.
Eckart
,
D. N.
Fittinghoff
,
S.
Friedrich
et al,
Nucl. Fusion
53
,
043014
(
2013
).
42.
V. Y.
Glebov
,
T. C.
Sangster
,
C.
Stoeckl
,
J. P.
Knauer
,
W.
Theobald
,
K. L.
Marshall
,
M. J.
Shoup
III
,
T.
Buczek
,
M.
Cruz
,
T.
Duffy
et al, “
The National Ignition Facility neutron time-of-flight system and its initial performance
,”
Rev. Sci. Instrum.
81
,
10D325
(
2010
).
43.
O. L.
Landen
,
D. T.
Casey
,
J. M.
DiNicola
,
T.
Doeppner
,
E. P.
Hartouni
,
D. E.
Hinkel
,
L. F.
Berzak Hopkins
,
M.
Hohenberger
,
A. L.
Kritcher
,
S.
LePape
et al,
High Energy Density Phys.
36
,
100755
(
2020
).
44.
A. J.
MacKinnon
,
N. B.
Meezan
,
J. S.
Ross
,
S.
Le Pape
,
L.
Berzak Hopkins
,
L.
Divol
,
D.
Ho
,
J.
Milovich
,
A.
Pak
,
J.
Ralph
et al, “
High-density carbon ablator experiments on the National Ignition Facility
,”
Phys. Plasmas
21
,
056318
(
2014
).
45.
S.
Ali
,
P.
Celliers
,
S.
Haan
,
T.
Boehly
,
N.
Whiting
,
S.
Baxamusa
,
H.
Reynolds
,
M.
Johnson
,
J.
Hughes
, and
B.
Watson
,
Phys. Plasmas
25
,
092708
(
2018
).
46.
M. J.
Edwards
,
P. K.
Patel
,
J. D.
Lindl
,
L. J.
Atherton
,
S. H.
Glenzer
,
S. W.
Haan
,
J. D.
Kilkenny
,
O. L.
Landen
,
E. I.
Moses
,
A.
Nikroo
et al, “
Progress towards ignition on the National Ignition Facility
,”
Phys. Plasmas.
20
,
070501
(
2013
).
47.
D. T.
Casey
,
J. L.
Milovich
,
V. A.
Smalyuk
,
D. S.
Clark
,
H. F.
Robey
,
A.
Pak
,
A. G.
MacPhee
,
K. L.
Baker
,
C. R.
Weber
,
T.
Ma
et al, “
Improved performance of high areal density indirect drive implosions at the National Ignition Facility using a four-shock adiabat shaped drive
,”
Phys. Rev. Lett.
115
,
105001
(
2015
).
48.
V. A.
Smalyuk
,
L. J.
Atherton
,
L. R.
Benedetti
,
R.
Bionta
,
D.
Bleuel
,
E.
Bond
,
D. K.
Bradley
,
J.
Caggiano
,
D. A.
Callahan
,
D. T.
Casey
et al,
Phys. Rev. Lett.
111
,
215001
(
2013
).
You do not currently have access to this content.