Plasma and Fusion Research

Volume 18, 2404061 (2023)

Regular Articles

Effect of Kilo-Tesla Magnetic Fields on Ignition and Burn Dynamics in Fast Ignition Laser Fusion
Naoki MATSUMURA1), Tomoyuki JOHZAKI1,2), Wookyung KIM1) and Takuma ENDO1)
1)
Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima 739-8527, Japan
2)
Institute of Laser Engineering, Osaka University, Suita 565-0871, Japan
(Received 8 January 2023 / Accepted 7 June 2023 / Published 28 August 2023)

Abstract

In fast ignition laser fusion, electron beam guiding with a kilo-tesla magnetic field has been proposed to avoid divergence of the beam, which significantly enhances the core heating efficiency. In addition to beam guiding, magnetic fields affect electron heat conduction and alpha particle energy transport. The objective of this study is to estimate the effect of a magnetic field on ignition and burn propagation dynamics of a high-gain target in fast ignition (FI) laser fusion based on axially symmetric two-dimensional burn simulations. A uniformly compressed DT plasma sphere with a cylindrical hot spot was assumed as the initial condition. A magnetic field of 100 kT was applied along the symmetrical axis. In the ignition phase, the suppression of the alpha particle flux and heat conduction by the magnetic field fastens temperature rise in the hot spot. However, the magnetic field reduced the burn propagation speed and then increased the burning time, which enhanced the erosion of the fuel edge by rarefaction waves and decreased the effective areal density of the fuel. Consequently, the burnup fraction for a 100 kT magnetic field was 11% lower than that without a magnetic field.

Keywords

fast ignition, laser fusion, alpha particle transport, electron heat conduction, kilo-tesla magnetic field, radiation-hydro simulation

DOI: 10.1585/pfr.18.2404061

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References

  • [1] M. Tabak et al., Phys. Plasmas 1, 1626 (1994).
  • [2] J. Nuckolls et al., Nature 239, 139 (1972).
  • [3] D.J. Strozzi et al., Phys. Plasmas 19, 072711 (2012).
  • [4] H. Nagatomo et al., Nucl. Fusion 57, 086009 (2017).
  • [5] T. Johzaki et al., Plasma Phys. Control. Fusion 59, 014045 (2017).
  • [6] S. Sakata et al., Nat. Commun. 9, 3937 (2018).
  • [7] H. Daido et al., Phys. Rev. Lett. 56, 846 (1986).
  • [8] K.F.F. Law et al., Appl. Phys. Lett. 108, 091104 (2016).
  • [9] C.A. Walsh et al., Phys. Plasmas 26, 022701 (2019).
  • [10] S.A. Slutz and R.A. Vesey, Phys. Rev. Lett. 108, 025003 (2012).
  • [11] B. Appelbe et al., Phys. Plasmas 28, 032705 (2021).
  • [12] T. Johzaki et al., High Energy Density Phys. 36, 100841 (2020).
  • [13] J.P. Knauer et al., Phys. Plasmas 17, 056318 (2010).
  • [14] T. Johzaki et al., J. Phys. IV France 133, 385 (2006).
  • [15] R.M. More et al., Phys. Fluids 31, 3059 (1988).
  • [16] J. Young Ji and E.D. Held, Phys. Plasmas 20, 042114 (2013).
  • [17] C. Li and R.D. Petrasso, Phys. Rev. Lett. 70, 3059 (1993), Erratum-ibid. 114 199901 (2015).
  • [18] J.F. Hawley and J.M. Stone, Comput. Phys. Commun. 89, 127 (1995).
  • [19] H. Nagatomo et al., Nucl. Fusion 55, 093028 (2015).