Shock Ignition: A New Approach to High Gain Inertial Confinement Fusion on the National Ignition Facility

Abstract

Shock ignition, an alternative concept for igniting thermonuclear fuel, is explored as a new approach to high gain, inertial confinement fusion targets for the National Ignition Facility (NIF). Results indicate thermonuclear yields of approximately 120-250 MJ may be possible with laser drive energies of 1-1.6 MJ, while gains of approximately 50 may still be achievable at only approximately 0.2 MJ drive energy. The scaling of NIF energy gain with laser energy is found to be G approximately 126E (MJ);{0.510}. This offers the potential for high-gain targets that may lead to smaller, more economic fusion power reactors and a cheaper fusion energy development path.

Simulation of stimulated Brillouin scattering and stimulated Raman scattering in shock ignition

“…The key process in SI is to generate a strong shock at the end of the compression stage by escalating the intensity of the incident laser to 10 15 ∼ 10 16 W/cm 2 [1,2]. In this high laser intensity regime, growth rates of many laser plasma instabilities (LPI) exceed their thresholds, such as the two plasmon decay (TPD), the stimulated Raman scattering (SRS), and the stimulated Brillouin scattering (SBS).…”

Laser requirements for a laser fusion energy power plant

“…A full test of this instability in the physical regime of the target designs will have to await a test with larger laser facilities than are currently available. The final ignitor pulse is well above instability threshold, but preheating from suprathermal electrons in this part of the pulse is not expected to be dangerous [14] unless the suprathermal electron energy exceeds 100-150 keV.…”

Low initial aspect-ratio direct-drive target designs for shock- or self-ignition in the context of the laser Megajoule

“…NRL has also addressed the interest of shock-ignition for the NIKE KrF laser project for sub-megajoule designs [3,24,41]. For NIF- [40] and LMJ-class [38] facilities, high thermonuclear gains are expected in direct drive approach. While NIF could mainly use the PDD [16,17], DD studies, in the context of LMJ, have exhibited the importance of illumination uniformity [48][49][50] to warrant fuel assembly sphericity in order to reduce ignitor spike powers [51].…”