High-Gain Magnetized Inertial Fusion

Magnetized inertial fusion (MIF) could substantially ease the difficulty of reaching plasma conditions required for significant fusion yields, but it has been widely accepted that the gain is not sufficient for fusion energy. Numerical simulations are presented showing that high-gain MIF is possible in cylindrical liner implosions based on the MagLIF concept [S. A. Slutz et al Phys. Plasmas 17, 056303 (2010)] with the addition of a cryogenic layer of deuterium-tritium (DT). These simulations show that a burn wave propagates radially from the magnetized hot spot into the surrounding much denser cold DT given sufficient hot-spot areal density. For a drive current of 60 MA the simulated gain exceeds 100, which is more than adequate for fusion energy applications. The simulated gain exceeds 1000 for a drive current of 70 MA.

Figure 1

Schematic of a high-gain MagLIF.

Figure 2

Contours of the ratio $Y_{\mathrm{cold}}/Y_{\mathrm{hot}}$ from simulations are plotted (color shading and black curves). Regions of $Y_{\mathrm{cold}}/Y_{\mathrm{hot}}>1$ indicate propagating burn. The white dotted line corresponds to peak fuel temperature equal to 15 keV and indicates hot-spot ignition. This occurs at much lower hot-spot areal density than propagation. The areal density of the metal liner was $5.0\mathrm{g}/{\mathrm{cm}}^2$ in these simulations.

Figure 3

Simulated yields (solid curves) and gains (dashed curves) plotted as a function of peak drive current. The black curves are for standard MagLIF while the colored curves are the results for MagLIF simulations that include a cryogenic layer of DT ice on the inner surface of a liner (beryllium shown as red, aluminum as blue).

Figure 4

Contours of optimum initial magnetic field (black curves and colored background) and contours of constant yield (white curves) are plotted as a function of the logarithm of two arbitrary multipliers $M_{\alpha }$ and $M_e$ described in the text.

Figure 5

Simulated 2D yields plotted as a function of RMS surface roughness for different axial resolutions. Curves are labeled with the minimum resolved wavelength in $\mu \mathrm{m}$.