Arc-based smoothing of ion beam intensity on targets
Abstract
By manipulating a set of ion beams upstream of a target, it is possible to arrange for a smoother deposition pattern, so as to achieve more uniform illumination of the target. A uniform energy deposition pattern is important for applications including ion-beam-driven high energy density physics and heavy-ion beam-driven inertial fusion energy ('heavy-ion fusion'). Here, we consider an approach to such smoothing that is based on rapidly 'wobbling' each of the beams back and forth along a short arc-shaped path, via oscillating fields applied upstream of the final pulse compression. In this technique, uniformity is achieved in the time-averaged sense; this is sufficient provided the beam oscillation timescale is short relative to the hydrodynamic timescale of the target implosion. This work builds on two earlier concepts: elliptical beams applied to a distributed-radiator target [D. A. Callahan and M. Tabak, Phys. Plasmas 7, 2083 (2000)] and beams that are wobbled so as to trace a number of full rotations around a circular or elliptical path [R. C. Arnold et al., Nucl. Instrum. Methods 199, 557 (1982)]. Here, we describe the arc-based smoothing approach and compare it to results obtainable using an elliptical-beam prescription. In particular, we assess the potential of thesemore »
- Authors:
-
- Lawrence Livermore National Laboratory, Livermore, California 94550 (United States) and The Virtual National Laboratory for Heavy Ion Fusion Science (United States)
- Publication Date:
- OSTI Identifier:
- 22072490
- Resource Type:
- Journal Article
- Journal Name:
- Physics of Plasmas
- Additional Journal Information:
- Journal Volume: 19; Journal Issue: 6; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 43 PARTICLE ACCELERATORS; ASYMMETRY; DEPOSITION; ENERGY DENSITY; HEAVY IONS; ICF DEVICES; IMPLOSIONS; INERTIAL FUSION DRIVERS; ION BEAM TARGETS; ION BEAMS; OSCILLATIONS; RADIATORS; ROTATION
Citation Formats
Friedman, Alex. Arc-based smoothing of ion beam intensity on targets. United States: N. p., 2012.
Web. doi:10.1063/1.4729841.
Friedman, Alex. Arc-based smoothing of ion beam intensity on targets. United States. https://doi.org/10.1063/1.4729841
Friedman, Alex. 2012.
"Arc-based smoothing of ion beam intensity on targets". United States. https://doi.org/10.1063/1.4729841.
@article{osti_22072490,
title = {Arc-based smoothing of ion beam intensity on targets},
author = {Friedman, Alex},
abstractNote = {By manipulating a set of ion beams upstream of a target, it is possible to arrange for a smoother deposition pattern, so as to achieve more uniform illumination of the target. A uniform energy deposition pattern is important for applications including ion-beam-driven high energy density physics and heavy-ion beam-driven inertial fusion energy ('heavy-ion fusion'). Here, we consider an approach to such smoothing that is based on rapidly 'wobbling' each of the beams back and forth along a short arc-shaped path, via oscillating fields applied upstream of the final pulse compression. In this technique, uniformity is achieved in the time-averaged sense; this is sufficient provided the beam oscillation timescale is short relative to the hydrodynamic timescale of the target implosion. This work builds on two earlier concepts: elliptical beams applied to a distributed-radiator target [D. A. Callahan and M. Tabak, Phys. Plasmas 7, 2083 (2000)] and beams that are wobbled so as to trace a number of full rotations around a circular or elliptical path [R. C. Arnold et al., Nucl. Instrum. Methods 199, 557 (1982)]. Here, we describe the arc-based smoothing approach and compare it to results obtainable using an elliptical-beam prescription. In particular, we assess the potential of these approaches for minimization of azimuthal asymmetry, for the case of a ring of beams arranged on a cone. It is found that, for small numbers of beams on the ring, the arc-based smoothing approach offers superior uniformity. In contrast with the full-rotation approach, arc-based smoothing remains usable when the geometry precludes wobbling the beams around a full circle, e.g., for the X-target [E. Henestroza, B. G. Logan, and L. J. Perkins, Phys. Plasmas 18, 032702 (2011)] and some classes of distributed-radiator targets.},
doi = {10.1063/1.4729841},
url = {https://www.osti.gov/biblio/22072490},
journal = {Physics of Plasmas},
issn = {1070-664X},
number = 6,
volume = 19,
place = {United States},
year = {Fri Jun 15 00:00:00 EDT 2012},
month = {Fri Jun 15 00:00:00 EDT 2012}
}