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Title: Nuclear Diagnostics of ICF

Abstract

In inertial confinement fusion (ICF), a high temperature and high density plasma is produced by the spherical implosion of a small capsule. A spherical target capsule is irradiated uniformly by a laser beam (direct irradiation) or x-rays from a high Z enclosure (hohlraum) that is irradiated by laser or ion beams (indirect irradiation). Then high-pressure ablation of the surface causes the fuel to be accelerated inward. Thermonuclear fusion reactions begin in the center region of the capsule as it is heated to sufficient temperature (10 keV) by the converging shocks (hot spot formation). During the stagnation of the imploded shell, the fuel in the shell region is compressed to high density ({approx} 10{sup 3} times solid density in fuel region). When these conditions are established, energy released by the initial nuclear reactions in center ''hot-spot'' region can heat up the cold ''fuel'' region and cause ignition. They are developing advanced nuclear diagnostics for imploding plasmas of the ignition campaign on the National Ignition Facility (NIF). The NIF is a 1.8MJ, 192-beam glass laser system that is under construction at Lawrence Livermore National Laboratory. One objective of the NIF is to demonstrate ignition and gain in an inertial confinement fusion plasma.more » Extreme physical conditions characterize the imploded plasmas on the NIF. First, the thickness of the plasma, expressed by areal density (plasma density times radius), is large, up to {approx} 1 g/cm{sup 2}. Highly penetrating probes such as energetic neutrons, hard x-rays, or {gamma} rays are required to see deep inside the plasma. Second, the implosion time is quite short. The implosion process takes {approx} 20 ns and the duration of the fusion reaction is on the order of 100 picoseconds. To observe the time history of the nuclear reactions, time resolution better than 10 ps is required. Third, the size of the imploded plasma is quite small ({approx} 100 {micro}m). To see the shape of burning region, a spatial resolution of {approx} 5 {micro}m is required for imaging systems. Fourth, the diagnostics operate in a harsh background. In implosion experiments, strong bursts of electromagnetic pulses, x-rays, neutrons, and neutron-induced radioactivity are produced. Therefore the diagnostics have to be designed to survive in these backgrounds. In addition, to prevent materials ablated from diagnostic components close to the target from being deposited on the laser optics, these components are excluded from a zone around the target with a radius in the range of 0.5 m to 5 m. This exclusion zone has a large impact on diagnostic design.« less

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »; ; ; ; ; « less
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
15013377
Report Number(s):
UCRL-JC-144322
TRN: US0600128
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Conference
Resource Relation:
Conference: International Conference on Advanced Diagnostics for Magnetic and Inertial Fusion, Varenna, Italy, Sep 03 - Sep 07, 2001
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ELECTROMAGNETIC PULSES; INERTIAL CONFINEMENT; IMPLOSIONS; ION BEAMS; IRRADIATION; LAWRENCE LIVERMORE NATIONAL LABORATORY; NEUTRONS; NUCLEAR REACTIONS; RADIOACTIVITY; SPATIAL RESOLUTION; TIME RESOLUTION; US NATIONAL IGNITION FACILITY

Citation Formats

Izumi, N, Ierche, R A, Moran, M J, Phillips, T W, Sangster, T C, Schmid, G J, Stoyer, M A, Disdier, L, Bourgade, J L, Rouyer, A, Fisher, R K, Gerggren, R R, Caldwen, S E, Faulkner, J R, Mack, J M, Oertel, J A, Young, C S, Glebov, V Y, Jaanimagi, P A, Meyerhofer, D D, Soures, J M, Stockel, C, Frenje, J A, Li, C K, and Petrasso, R D. Nuclear Diagnostics of ICF. United States: N. p., 2001. Web. doi:10.1007/978-1-4419-8696-2_15.
Izumi, N, Ierche, R A, Moran, M J, Phillips, T W, Sangster, T C, Schmid, G J, Stoyer, M A, Disdier, L, Bourgade, J L, Rouyer, A, Fisher, R K, Gerggren, R R, Caldwen, S E, Faulkner, J R, Mack, J M, Oertel, J A, Young, C S, Glebov, V Y, Jaanimagi, P A, Meyerhofer, D D, Soures, J M, Stockel, C, Frenje, J A, Li, C K, & Petrasso, R D. Nuclear Diagnostics of ICF. United States. doi:10.1007/978-1-4419-8696-2_15.
Izumi, N, Ierche, R A, Moran, M J, Phillips, T W, Sangster, T C, Schmid, G J, Stoyer, M A, Disdier, L, Bourgade, J L, Rouyer, A, Fisher, R K, Gerggren, R R, Caldwen, S E, Faulkner, J R, Mack, J M, Oertel, J A, Young, C S, Glebov, V Y, Jaanimagi, P A, Meyerhofer, D D, Soures, J M, Stockel, C, Frenje, J A, Li, C K, and Petrasso, R D. Thu . "Nuclear Diagnostics of ICF". United States. doi:10.1007/978-1-4419-8696-2_15. https://www.osti.gov/servlets/purl/15013377.
@article{osti_15013377,
title = {Nuclear Diagnostics of ICF},
author = {Izumi, N and Ierche, R A and Moran, M J and Phillips, T W and Sangster, T C and Schmid, G J and Stoyer, M A and Disdier, L and Bourgade, J L and Rouyer, A and Fisher, R K and Gerggren, R R and Caldwen, S E and Faulkner, J R and Mack, J M and Oertel, J A and Young, C S and Glebov, V Y and Jaanimagi, P A and Meyerhofer, D D and Soures, J M and Stockel, C and Frenje, J A and Li, C K and Petrasso, R D},
abstractNote = {In inertial confinement fusion (ICF), a high temperature and high density plasma is produced by the spherical implosion of a small capsule. A spherical target capsule is irradiated uniformly by a laser beam (direct irradiation) or x-rays from a high Z enclosure (hohlraum) that is irradiated by laser or ion beams (indirect irradiation). Then high-pressure ablation of the surface causes the fuel to be accelerated inward. Thermonuclear fusion reactions begin in the center region of the capsule as it is heated to sufficient temperature (10 keV) by the converging shocks (hot spot formation). During the stagnation of the imploded shell, the fuel in the shell region is compressed to high density ({approx} 10{sup 3} times solid density in fuel region). When these conditions are established, energy released by the initial nuclear reactions in center ''hot-spot'' region can heat up the cold ''fuel'' region and cause ignition. They are developing advanced nuclear diagnostics for imploding plasmas of the ignition campaign on the National Ignition Facility (NIF). The NIF is a 1.8MJ, 192-beam glass laser system that is under construction at Lawrence Livermore National Laboratory. One objective of the NIF is to demonstrate ignition and gain in an inertial confinement fusion plasma. Extreme physical conditions characterize the imploded plasmas on the NIF. First, the thickness of the plasma, expressed by areal density (plasma density times radius), is large, up to {approx} 1 g/cm{sup 2}. Highly penetrating probes such as energetic neutrons, hard x-rays, or {gamma} rays are required to see deep inside the plasma. Second, the implosion time is quite short. The implosion process takes {approx} 20 ns and the duration of the fusion reaction is on the order of 100 picoseconds. To observe the time history of the nuclear reactions, time resolution better than 10 ps is required. Third, the size of the imploded plasma is quite small ({approx} 100 {micro}m). To see the shape of burning region, a spatial resolution of {approx} 5 {micro}m is required for imaging systems. Fourth, the diagnostics operate in a harsh background. In implosion experiments, strong bursts of electromagnetic pulses, x-rays, neutrons, and neutron-induced radioactivity are produced. Therefore the diagnostics have to be designed to survive in these backgrounds. In addition, to prevent materials ablated from diagnostic components close to the target from being deposited on the laser optics, these components are excluded from a zone around the target with a radius in the range of 0.5 m to 5 m. This exclusion zone has a large impact on diagnostic design.},
doi = {10.1007/978-1-4419-8696-2_15},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2001},
month = {10}
}

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