147 / 2025-03-15 20:47:19

Localized end-on heating for hotspot ignition in precompressed Isochoric plasmas

fast ignition,integrated simulation

In the fast ignition inertial confinement fusion (FI) scheme, inserting a guiding cone shortens the transport distance of the relativistic electron beam (REB) through the 100 μm-scale low-density region at the plasma edge, thereby reducing energy loss. However, the insertion depth of the heating cone is constrained by the pressure at the plasma edge and the temporal duration of its interaction with the plasma. In the double-cone ignition (DCI) scheme, head-on collision of two low-entropy DT plasma jets naturally forms a high-density isochoric plasma with sharp ends. The interaction time of the heating cone with the plasma is reduced from 1 ns to 0.2 ns, and the insertion depth from

the high-density plateau can be decreased to 30 μm while maintaining the structural integrity of the cone, improving the REB transport efficiency. Additionally, magnetohydrodynamic simulations of plasma jet collision, which self-consistently include the effect of magnetic flux freezing, demonstrate that an external magnetic field of only 80 T can be effectively amplified to over 2 kT, thus enabling efficient collimation of a soft-spectrum REB to a localized hotspot. Our multi-scale simulations identify the optimal ignition timing under 160 kJ laser compression, achieving fusion ignition with a gain of 6.8 using a 60 kJ heating laser.