On December 5, 2022, an indirect drive fusion implosion on the National Ignition Facility (NIF) achieved a target gain G_{target} of 1.5. This is the first laboratory demonstration of exceeding "scientific breakeven" (or G_{target}>1) where 2.05 MJ of 351 nm laser light produced 3.1 MJ of total fusion yield, a result which significantly exceeds the Lawson criterion for fusion ignition as reported in a previous NIF implosion [H. Abu-Shawareb et al. (Indirect Drive ICF Collaboration), Phys. Rev. Lett. 129, 075001 (2022)PRLTAO0031-900710.1103/PhysRevLett.129.075001]. This achievement is the culmination of more than five decades of research and gives proof that laboratory fusion, based on fundamental physics principles, is possible. This Letter reports on the target, laser, design, and experimental advancements that led to this result.

We have developed a conceptual design of a next-generation pulsed-power accelerator that is optimized for advanced high-energy-density-physics experiments. The prime power source of the machine consists of 210 impedance-matched Marx generators (IMGs). Each IMG drives a 150-ns-long coaxial-transmission-line impedance transformer. The coaxial lines provide a minimum of 300 ns of transit-time isolation between each pair of IMGs. The lines in turn drive six radial-transmission-line impedance transformers, which transport the power generated by the IMGs to a six-level vacuum-insulator stack. The stack is connected to six conical outer magnetically insulated vacuum transmission lines (MITLs); these are joined in parallel at a 12-cm radius by a triple-post-hole vacuum convolute. The convolute sums the electrical currents at the outputs of the six outer MITLs, and delivers the combined current to a single short inner MITL. The inner MITL transmits the combined current to the accelerator's physics load. Since the accelerator would be the largest and most-powerful pulsed-power machine developed to date, we refer to it as Jupiter. The conceptual design of Jupiter is 72 m in diameter, stores 140 MJ of electrical energy, and generates 960 TW of peak electrical power at the output of the IMG system. The design delivers 2700 TW, 67 MA, and 9.2 MJ in a 110-ns pulse to a 0D magnetized-liner inertial-fusion (MagLIF) target. The principal goal of the design is to achieve high-yield thermonuclear fusion; i.e., a fusion yield that exceeds the energy initially stored by the accelerator's capacitors.

We disucss the line broadening analysis of argon‐doped deuterium‐filled implosion cores driven by a dynamic hohlraum z‐pinch. The observed line spectra include emissions from the Lyα, Lyβ, Lyγ, Heα, Heβ, Heγ and Heδ lines in H‐ and He‐like argon ions, respectively. The data recorded using a crystal spectrometer with space‐resolving slits and coupled to a framing camera yields time‐ and spatially‐resolved argon line spectra in the implosion core. The analysis accounts for opacity and Stark line broadening to determine electron density, Ne, and areal‐density, NΔR, values for the ground state populations of H‐ and He‐like argon ions. In this connection, a set of Stark‐broadened line shapes was computed considering the effect of differing ion and electron temperatures, which impacts the calculation of the ion microfield distribution function, the Doppler broadening, and the ion dynamic’s effect. Analysis results will be discussed emphasizing the relevance of using these detailed Stark‐broadened line shapes.

Numerical simulations indicate that significant fusion yields (>100 kJ) may be obtained by pulsed-power-driven implosions of cylindrical metal liners onto magnetized and preheated deuterium-tritium fuel. The primary physics risk to this approach is the Magneto-Rayleigh-Taylor (MRT) instability, which operates during both the acceleration and deceleration phase of the liner implosion. We have designed and performed some experiments to study the MRT during the acceleration phase, where the light fluid is purely magnetic. Results from our first series of experiments and plans for future experiments will be presented. According to simulations, an initial axial magnetic field of 10 T is compressed to >100 MG within the liner during the implosion. The magnetic pressure becomes comparable to the plasma pressure during deceleration, which could significantly affect the growth of the MRT instability at the fuel/liner interface. The MRT instability is also important in some astronomical objects such as the Crab Nebula (NGC1962). In particular, the morphological structure of the observed filaments may be determined by the ratio of the magnetic to material pressure and alignment of the magnetic field with the direction of acceleration [Hester, ApJ, 456, 225 1996]. Potential experiments to study this MRT behavior using the Z facility will bemore » presented.« less