Speaker
Henry Watkins
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P5.2001.pdf
Magnetised Thermal Filamentation and Self-Focussing Laser-Plasmas
H. C. Watkins1, R. J. Kingham1
1
Imperial College London, London, United Kingdom
The use of magnetic fields in Inertial Confinement Fusion (ICF) experiment 1,2 requires the
introduction of the Braginskii magnetised anisotropic transport coefficients3. We study the
effect of the magnetised thermal conductivity on the propagation of a long-pulse laser in the
underdense plasma regime relevant to ICF parameters. An analytic model is derived for the
laser self-focussing and shows the shortening of the self-focal length of a laser beam in a
plasma because of the magnetised reduction of the plasma thermal conductivity.
Furthermore the thermal mechanism filamentation4,5 of a laser under a magnetised plasma
has an increased spatial growth rate. These analytic results are compared with the
PARAMAGNET laser-plasma code and found to be in good agreement. We discuss the
effect of these results on recent magnetised inertial fusion experiments where filamentation
can be detrimental to laser propagation and uniform laser heating. The application of
external magnetic fields to laser-plasma experiments requires the inclusion of the extended
electron transport terms in simulation6.
References:
1
D.S. Montgomery, B.J. Albright, D.H. Barnak, P.Y. Chang, J.R. Davies, G. Fiksel, D.H.
Froula, J.L. Kline, M.J. Macdonald, A.B. Sefkow, L. Yin, and R. Betti, Phys. Plasmas
10703, (2015).
2
L.J. Perkins, D.D.M. Ho, B.G. Logan, G.B. Zimmerman, M.A. Rhodes, D.J. Strozzi, D.T.
Blackfield, and S.A. Hawkins, Phys. Plasmas (2017).
3
S. I. Braginskii, Rev. Plasma Phys. (1965).
4
E.M. Epperlein, Phys. Rev. Lett. 65, 2145 (1990).
5
P. Kaw, G. Schmidt, and T. Wilcox, Phys. Fluids 1522, (1988).
6
M. Read, R. Kingham, and J. Bissell, in J. Phys. Conf. Ser. (2016), p. 12111.
