Dettagli Progetti e Finanziamenti

Abstract: We aim to study and unlock key issues of the physics of laser direct-drive (DD) inertial fusion, and Shock Ignition (SI) in particular. Indeed, inertial fusion energy (IFE) requires high-gain, hardly compatible with the indirect-drive approach investigated at NIF and other major facilities. Our project would therefore complement the NIF approach by studying the physics of potentially higher-gain DD schemes. SI is based on separation of compression and ignition. First, the target is compressed and then a highintensity spike of several-hundred ps launches a strong shock (>300 Mbar) igniting the precompressed fuel. Since compression does not need to create a hot spot, implosion can take place at lower velocity and with thicker targets, reducing the impact of hydro instabilities. SI demonstration is compatible with
present-day laser technology and, with some modifications, target areas. In this respect, SI is one of the few IFE schemes that can be tested at ignition-scale within the next decade on facilities like NIF, LMJ, SGIII. The project is organized in five Work Packages, each including experiments and theory:
• WP1: characterization of hot electrons and hot-electron-driven SI;
• WP2: hydrodynamic instabilities and mitigation strategies in DD-SI, including use of foams;
• WP3: bipolar SI: direct drive compression and bipolar spike irradiation;
• WP4: parametric instabilities and cross beam energy transfer, and their mitigation using broadband lasers;
• WP5: magnetic-field-assisted inertial fusion implosion and ignition.
We emphasize the coupling of theory and experiments, especially the development of theoretically-based simulation tools relevant to DD and SI. In addition to usual radiation-hydrodynamics and nuclear packages, these include self-consistent description of parametric instabilities, hot electron generation, non-local electron transport, magnetic flux compression, etc. State-of-the-art codes, developed by the proponents (CHIC, DUED, IFRIIT) or made available to the proponents (ASTER, FLASH) will be used. We plan to perform experiments at European laser facilities, in particular PALS, currently the only facility in Europe allowing intensities of 1e16 W/cm2 in a sub-ns pulse, VULCAN, offering the possibility of multibeam irradiation, and LMJ/PETAL which will allow realizing experiments at full IFE scale. In addition, we
will collaborate with overseas groups and Large facilities: Omega (LLE, Rochester), Gekko (Osaka), SG II and III (China).
The present project builds on physics and community building achievements of our previous Enabling Research project ENR-IFE19.CEA-01 “Study of Direct Drive and Shock Ignition for IFE: Theory, Simulations, Experiments, Diagnostics development”. In particular, we will continue the fruitful collaboration with Rochester University, the birthplace of SI. Our objectives are answering key physics issues on SI and DD, consolidating the European community doing DD research, with the longer-term objective of designing and performing SI demonstration on NIF or LMJ.