Abstract
Transport and implosion experiments have been conducted on the OMEGA, 24-beam, uniform-irradiation facility that may result in significant revisions in our current understanding of thermal transport in laser-irradiated targets:
-
(a)
Thermal transport in spherical irradiation cannot be described in terms of a simple flux-limited inhibition model.
-
(b)
Classical transport is found to be inadequate also: the heat front has a different shape (falling more gradually) than that predicted by either classical or flux-limited transport models for any level of inhibition.
-
(c)
A multi-group (non-local) treatment of transport in which faster than the average thermal electrons penetrate deeper, results in a temperature profile which is in qualitative agreement with the present measurements.
-
(d)
The enhanced inward penetration studied here appears to supercede preheat by resonance-absorption electrons, but to have a weaker dependence on the irradiance than is the case for the latter mechanism; this would reduce the incentive to go to lower irradiance in order to reduce preheat.
-
(e)
Target implosion experiments show higher core temperatures than predicted by an inhibited flux model and lower densities than predicted by an uninhibited flux model.
-
(f)
Single-beam plane-target experiments appear to show flux inhibition only because of some 2D effects; these may be subtler than simple lateral heat transport.
-
(g)
There are indications that in short wavelength irradiation the higher collisionality suppresses the deeper penetration measured here. This would mean that for the same absorbed irradiance the shorter wavelength laser produces a higher pressure gradient (and efficiency).
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References
T.J. Goldsack, J.D. Kilkenny, B.J. MacGowan, P.F. Cunningham, C.L.S. Lewis, M.H. Key, and P.T. Rumsby, Phys. Fluids 25:1634 (1982).
B. Yaakobi, T. Boehly, P. Bourke, Y. Conturie, R.S. Craxton, J. Delettrez, J.M. Forsyth, R.D. Frankel, L.M. Goldman, R.L. McCrory, M.C. Richardson, W. Seka, D. Shvarts, and J.M. Soures, Optics Comm. 39:175 (1981).
Crystals calibrated by A.J. Burek, National Bureau of Standards, Gaithersburg, MD 20760. Our film calibration results agree (except for very high exposures) with published data: R.F. Benjamin, P.B. Lyons, and R.H. Day, App. Optics 16:393 (1977),
Crystals calibrated by A.J. Burek, National Bureau of Standards, Gaithersburg, MD 20760. Our film calibration results agree (except for very high exposures) with published data: CM. Dozier, D.B. Brown, L.S. Birks, P.B. Lyons, and R.F. Benjamin, J. App. Phys. 47:3732 (1976).
Earlier versions of LILAC are described in Laboratory for Laser Energetics Reports No. 16 (1973) and No. 36 (1976).
R.C. Malone, R.L. McCrory, and R.L. Morse, Phys. Rev. Lett. 34:721 (1975).
M.D. Rosen, D.W. Phillion, V.C. Rupert, W.C. Mead, W.L. Kruer, J.J. Thompson, H.N. Korublum, V.W. Slivinsky, G.J. Caporaso, M.J. Boyle, and K.G. Tirsell, Phys. Fluids 22:2020 (1979).
F.C. Young, R.R. Whitlock, R. Decoste, B.H. Ripin, D.J. Nagel, J.A. Stamper, J.M. McMahon, and S.E. Bodner, App. Phys. Lett. 30:45 (1977).
R. Fabbro, E. Fabre, F. Amiranoff, C. Garban-Labaune, J. Virmont, M. Weinfeld, and C.E. Max, Phys. Rev. A26:2289 (1982).
D. Shvarts, J. Delettrez, R.L. McCrory, and C.P. Verdon, Phys. Rev. Lett. 47:247 (1981).
B. Yaakobi, J. Delettrez, L.M. Goldman, R.L. McCrory, W. Seka, and J.M. Soures, Optics Comm. 41:355 (1982).
Annual Report, Rutherford Laboratory, RL-81–040, Chap. 4.3 (1981).
The energy fraction which reaches the critical surface by tunneling and is converted to fast electrons is calculated by W.L. Kruer, Lawrence Livermore Laboratory Report UCRL-81896 (1978).
K. Estabrook and W.L. Kruer, Phys. Rev. Lett. 40:42 (1978).
Annual Report, Rutherford Laboratory, RL-81–040, p. 4.13 (1981).
R.J. Mason, Phys. Rev. Lett. 47:652 (1981).
A.R. Bell, R.G. Evans, and D.J. Nicholas, Phys. Rev. Lett. 46:247 (1981).
“Thermal electron heat front calculations under laser-matter interaction conditions,” D. Shvarts, J. Delettrez, and R.L. McCrory (submitted for publication).
Annual Report, Rutherford Laboratory, RL-81–040, Chap. 4.4 (1981).
J. Murdoch, J.D. Kilkenny, D.R. Gray, and W.T. Toner, Phys. Fluids 24:2107 (1981).
D.W. Forslund and J.U. Brackbill, Phys. Rev. Lett. 48:1614 (1982).
J.G. Lunney and J.F. Seely, J. Phys. B15, L121 (1982).
P.C. Kepple and H.R. Griem, NRL Memorandum Report 3634 (1978).
B. Yaakobi, D.M. Villeneuve, M.C. Richardson, J.M. Soures, R. Hutchison, and S. Letzring, Optics Comm. 43:343 (1982).
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Yaakobi, B. et al. (1984). Thermal Transport Measurements in 1.05 µm Laser Irradiation of Spherical Targets. In: Hora, H., Miley, G.H. (eds) Laser Interaction and Related Plasma Phenomena. Springer, Boston, MA. https://doi.org/10.1007/978-1-4615-7332-6_46
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