We report on planar target experiments conducted on the OMEGA-EP laser facility performed in the context of the shock ignition (SI) approach to inertial confinement fusion. The experiment aimed at characterizing the propagation of strong shock in matter and the generation of hot electrons (HEs), with laser parameters relevant to SI (1-ns UV laser beams with I ∼1016 W/cm2). Time-resolved radiographs of the propagating shock front were performed in order to study the hydrodynamic evolution. The hot-electron source was characterized in terms of Maxwellian temperature, Th, and laser to hot-electron energy conversion efficiency η using data from different x-ray spectrometers. The post-processing of these data gives a range of the possible values for Th and η [i.e., Th[keV] (20, 50) and η (2%, 13%)]. These values are used as input in hydrodynamic simulations to reproduce the results obtained in radiographs, thus constraining the range for the HE measurements. According to this procedure, we found that the laser converts ∼10% ± 4% of energy into hot electrons with Th = 27 ± 8 keV. The paper shows how the coupling of different diagnostics and numerical tools is required to sufficiently constrain the problem, solving the large ambiguity coming from the post-processing of spectrometers data. The effect of the hot electrons on the shock dynamics is then discussed, showing an increase in the pressure around the shock front. The low temperature found in this experiment without pre-compression laser pulses could be advantageous for the SI scheme, but the high conversion efficiency may lead to an increase in the shell adiabat, with detrimental effects on the implosion.

1.
V. A.
Shcherbakov
, “
Ignition of a laser-fusion target by a focusing shock wave
,”
Sov. J. Plasma Phys.
9
(
2
),
240
241
(
1983
).
2.
R.
Betti
,
C. D.
Zhou
,
K. S.
Anderson
,
L. J.
Perkins
,
W.
Theobald
, and
A. A.
Solodov
,
Phys. Rev. Lett.
98
,
155001
(
2007
).
3.
D.
Batani
,
S.
Baton
,
A.
Casner
,
S.
Depierreux
,
M.
Hohenberger
,
O.
Klimo
,
M.
Koenig
,
C.
Labaune
,
X.
Ribeyre
,
C.
Rousseaux
 et al,
Nucl. Fusion
54
,
054009
(
2014
).
4.
D. W.
Forslund
,
J. M.
Kindel
, and
E. L.
Lindman
,
Phys. Fluids
18
,
1002
(
1975
).
5.
W.
Kruer
,
The Physics of Laser Plasma Interactions
, Frontiers in Physics Series (
Westview Press
,
2003
).
6.
A.
Colatis
,
X.
Ribeyre
,
E. L.
Bel
,
G.
Duchateau
,
P.
Nicolai
, and
V.
Tikhonchuk
,
Phys. Plasmas
23
,
072703
(
2016
).
7.
S. Yu.
Gus'kov
,
P.
Kuchugov
,
R.
Yakhin
, and
N.
Zmitrenko
, “
The role of fast electron energy transfer in the problem of shock ignition of laser thermonuclear target
,”
High Energy Density Phys.
36
,
100835
(
2020
).
8.
S. Yu.
Gus'kov
,
X.
Ribeyre
,
M.
Touati
,
J.-L.
Feugeas
,
P.
Nicolai
, and
V.
Tikhonchuk
,
Phys. Rev. Lett.
109
,
255004
(
2012
).
9.
S. Yu.
Gus'kov
,
A.
Kasperczuk
,
T.
Pisarczyk
,
S.
Borodziuk
,
M.
Kalal
,
J.
Limpouch
,
J.
Ullschmied
,
E.
Krousky
,
K.
Masek
,
M.
Pfeifer
 et al, “
Efficiency of ablative loading of material upon the fast-electron transfer of absorbed laser energy
,”
Quantum Electron.
36
(
5
),
429
434
(
2006
).
10.
S. Y.
Gus'kov
,
N. N.
Demchenko
,
A.
Kasperczuk
,
T.
Pisarczyk
,
Z.
Kalinowska
,
T.
Chodukowski
,
O.
Renner
,
M.
Smid
,
E.
Krousky
,
M.
Pfeifer
 et al, “
Laser-driven ablation through fast electrons in PALS-experiment at the laser radiation intensity of 1–50 PW/cm2
,”
Laser Part. Beams
32
(
1
),
177
195
(
2014
).
11.
W.
Theobald
,
R.
Nora
,
W.
Seka
,
M.
Lafon
,
K. S.
Anderson
,
M.
Hohenberger
,
F. J.
Marshall
,
D. T.
Michel
,
A. A.
Solodov
,
C.
Stoeckl
 et al, “
Spherical strong-shock generation for shock-ignition inertial fusion
,”
Phys. Plasmas
22
,
056310
(
2015
).
12.
L.
Antonelli
,
J.
Trela
,
F.
Barbato
,
G.
Boutoux
,
P.
Nicolai
,
D.
Batani
,
V.
Tikhonchuk
,
D.
Mancelli
,
A.
Tentori
,
S.
Atzeni
 et al,
Phys. Plasmas
26
,
112708
(
2019
).
13.
D.
Batani
,
L.
Antonelli
,
F.
Barbato
,
G.
Boutoux
,
A.
Colaïtis
,
J.-L.
Feugeas
,
G.
Folpini
,
D.
Mancelli
,
P.
Nicolai
,
J.
Santos
 et al,
Nucl. Fusion
59
,
032012
(
2018
).
14.
M. J.
Rosenberg
,
A. A.
Solodov
,
J. F.
Myatt
,
W.
Seka
,
P.
Michel
,
M.
Hohenberger
,
R. W.
Short
,
R.
Epstein
,
S. P.
Regan
,
E. M.
Campbell
 et al, “
Origins and scaling of hot-electron preheat in ignition-scale direct-drive inertial confinement fusion experiments
,”
Phys. Rev. Lett.
120
(
5
),
055001
(
2018
).
15.
L. J.
Waxer
,
D. N.
Maywar
,
J. H.
Kelly
,
T. J.
Kessler
,
B. E.
Kruschwitz
,
S. J.
Loucks
,
R. L.
McCrory
,
D. D.
Meyerhofer
,
S. F. B.
Morse
,
C.
Stoeckl
 et al,
Opt. Photonics News
16
,
30
(
2005
).
16.
L. C.
Jarrott
,
M. S.
Wei
,
C.
McGuffey
,
F. N.
Beg
,
P. M.
Nilson
,
C.
Sorce
,
C.
Stoeckl
,
W.
Theoboald
,
H.
Sawada
,
R. B.
Stephens
 et al,
Rev. Sci. Instrum.
88
,
043110
(
2017
).
17.
P. M.
Nilson
,
F.
Ehrne
,
C.
Mileham
,
D.
Mastrosimone
,
R. K.
Jungquist
,
C.
Taylor
,
C. R.
Stillman
,
S. T.
Ivancic
,
R.
Boni
,
J.
Hassett
 et al,
Rev. Sci. Instrum.
87
,
11D504
(
2016
).
18.
C. D.
Chen
,
J. A.
King
,
M. H.
Key
,
K. U.
Akli
,
F. N.
Beg
,
H.
Chen
,
R. R.
Freeman
,
A.
Link
,
A. J.
Mackinnon
,
A. G.
MacPhee
 et al,
Rev. Sci. Instrum.
79
,
10E305
(
2008
).
19.
A.
Curcio
,
P.
Andreoli
,
M.
Cipriani
,
G.
Claps
,
F.
Consoli
,
G.
Cristofari
,
R.
De Angelis
,
D.
Giulietti
, and
F.
Ingenito
,
J. Instrum.
11
,
C05011
(
2016
).
20.
D. K.
Bradley
,
P. M.
Bell
,
J. D.
Kilkenny
,
R.
Hanks
,
O.
Landen
,
P. A.
Jaanimagi
,
P. W.
McKenty
, and
C. P.
Verdon
,
Rev. Sci. Instrum.
63
,
4813
(
1992
).
21.
O. V.
Gotchev
,
P. A.
Jaanimagi
,
J. P.
Knauer
,
F. J.
Marshall
, and
D. D.
Meyerhofer
,
Rev. Sci. Instrum.
75
,
4063
(
2004
).
22.
G.
Boutoux
,
D.
Batani
,
F.
Burgy
,
J.
Ducret
,
P.
Forestier-Colleoni
,
S.
Hulin
,
N.
Rabhi
,
A.
Duval
,
L.
Lecherbourg
 et al,
Rev. Sci. Instrum.
87
,
043108
(
2016
).
23.
S.
Agostinelli
,
J.
Allison
,
K.
Amako
,
J.
Apostolakis
,
H.
Araujo
,
P.
Arce
,
M.
Asai
,
D.
Axen
,
S.
Banerjee
,
G.
Barrand
 et al, “
GEANT4: A simulation toolkit
,”
Nucl. Instrum. Methods Phys. Res., Sect. A
506
,
250
(
2003
).
24.
F.
Salvat
,
PENELOPE: A Code System for Monte Carlo Simulation of Electron and Photon Transport
(
Nuclear Energy Agency
,
2019
).
25.
S.
Pucella
,
Fisica Dei Plasmi
(
Zanichelli
,
2014
).
26.
S. T.
Perkins
,
D. E.
Cullen
,
M. H.
Chen
,
J.
Rathkopf
,
J.
Scofield
, and
J. H.
Hubbell
,
Tables and Graphs of Atomic Subshell and Relaxation Data Derived from the LLNL Evaluated Atomic Data Library (EADL), Z = 1–100
(
US Department of Energy, Office of Scientific and Technical Information
,
1991
).
27.
X.
Llovet
,
C.
Powell
,
F.
Salvat
, and
A.
Jablonski
,
J. Phys. Chem. Ref. Data
43
,
013102
(
2014
).
28.
J.
Breil
,
S.
Galera
, and
P.-H.
Maire
,
Comput. Fluids
46
,
161
167
(
2011
).
29.
J. F.
Myatt
,
J. G.
Shaw
,
R. K.
Follett
,
D. H.
Edgell
,
D. H.
Froula
,
J. P.
Palastro
, and
V. N.
Goncharov
,
J. Comput. Phys.
399
,
108916
(
2019
).
30.
A.
Solodov
and
R.
Betti
,
Phys. Plasmas
15
,
042707
(
2008
).
31.
R. M.
More
, “
Plasma processes in non-ideal plasmas
,” in
29th Scottish Universities Sumner School in Physics Laser Plasma Interactions
(
1985
).
32.
C.
Li
and
R.
Petrasso
,
Phys. Rev. E
73
,
016402
(
2006
).
33.
D.
Watteau
, in
La Fusion Thermonuclaire Inertielle Par Laser: Linteraction Laser-Matire Part 1
, French Edition, edited by CEA (
CEA
,
1991
), Vol.
1
.
34.
P.
Palmeri
,
G.
Boutoux
,
D.
Batani
, and
P.
Quinet
,
Phys. Rev. E
92
,
033108
(
2015
).
35.
J. J.
MacFarlane
,
I. E.
Golovkin
,
P.
Wang
,
P. R.
Woodruff
, and
N. A.
Pereyra
,
High Energy Density Phys.
3
,
181
(
2007
).
36.
B.
Afeyan
and
E. A.
Williams
,
Phys. Fluids
28
,
3397
(
1985
).
37.
A.
Colatis
,
G.
Duchateau
,
X.
Ribeyre
,
Y.
Maheut
,
G.
Boutoux
,
L.
Antonelli
,
P.
Nicolai
,
D.
Batani
, and
V.
Tikhonchuk
,
Phys. Rev. E
92
,
041101
(
2015
).
38.
J.
Lindl
,
Phys. Plasmas
2
,
3933
(
1995
).
39.
M.
Hohenberger
,
W.
Theobald
,
S. X.
Hu
,
K. S.
Anderson
,
R.
Betti
,
T. R.
Boehly
,
A.
Casner
,
D. E.
Fratanduono
,
M.
Lafon
,
D. D.
Meyerhofer
 et al,
Phys. Plasmas
21
,
022702
(
2014
).
40.
S.
Zhang
,
C.
Krauland
,
J.
Peebles
,
J.
Li
,
F.
Beg
,
N.
Alexander
,
W.
Theobald
,
R.
Betti
,
D.
Haberberger
,
M.
Campbell
 et al,
Phys. Plasmas
27
,
023111
(
2020
).
41.
W.
Theobald
,
R.
Nora
,
M.
Lafon
,
A.
Casner
,
X.
Ribeyre
,
K.
Anderson
,
R.
Betti
,
J.
Delettrez
,
J.
Frenje
,
V.
Glebov
 et al,
Phys. Plasmas
19
,
102706
(
2012
).
42.
O.
Klimo
,
V. T.
Tikhonchuk
,
X.
Ribeyre
,
G.
Schurtz
,
C.
Riconda
,
S.
Weber
, and
J.
Limpouch
,
Phys. Plasmas
18
,
082709
(
2011
).
43.
B.
Yaakobi
,
P.-Y.
Chang
,
A.
Solodov
,
C.
Stoeckl
,
D.
Edgell
,
S.
Craxton
,
S.
Hu
,
J.
Myatt
,
F.
Marshall
,
W.
Seka
 et al,
Phys. Plasmas
19
,
012704
(
2012
).
44.
A. A.
Solodov
,
M. J.
Rosenberg
,
W.
Seka
,
J. F.
Myatt
,
M.
Hohenberger
,
R.
Epstein
,
C.
Stoeckl
,
R. W.
Short
,
S. P.
Regan
,
P.
Michel
,
T.
Chapman
 et al, “
Hot-electron generation at direct-drive ignition-relevant plasma conditions at the National Ignition Facility
,”
Phys. Plasmas
27
,
052706
(
2020
).
45.
E.
Moses
and
C.
Wuest
, “
The National Ignition Facility: Status and plans for laser fusion and high-energy-density experimental studies
,”
Fusion Sci. Technol.
43
,
420
427
(
2003
).
46.
S.
Baton
,
A.
Colatis
,
C.
Rousseaux
,
G.
Boutoux
,
S.
Brygoo
,
L.
Jacquet
,
M.
Koenig
,
D.
Batani
,
A.
Casner
,
E. L.
Bel
 et al,
High Energy Density Phys.
36
,
100796
(
2020
).
47.
M.
Touati
,
J.-L.
Feugeas
,
P.
Nicolai
,
J. J.
Santos
,
L.
Gremillet
, and
V. T.
Tikhonchuk
,
New J. Phys.
16
,
073014
(
2014
).
48.
R. M.
More
, in
Proceedings of 29th St. Andrews Scottish Universities Summer School in Physics Fife, Scotland
(
SUSSP Publications
,
Edinburgh
,
1985
).
49.
J. D.
Jackson
,
Classical Electrodynamics
(
Wiley
,
New York
,
1975
).
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