Search

The challenge in the field of inertial confinement fusion (ICF) research is related to the study of alternative schemes for fuel ignition on laser systems of medium and megajoule scales. At the moment, it is considered promising to use the method of shock ignition of fuel in a pre-compressed cryogenic target using a focused shock wave (shock- or self-ignition (SI) mode). To confirm the applicability of this scheme to ICF, it is necessary to develop technologies for mass-fabrication of the corresponding targets with a spherically symmetric cryogenic layer (hereinafter referred to as SI-targets). These targets have a low initial aspect ratio Acl (Acl = 3 and Acl = 5) because they are expected to be more hydrodynamically stable during implosion. The paper discusses the preparation of SI-targets for laser experiments using the free-standing target (FST) layering method developed at the Lebedev Physical Institute (LPI). It is shown that, based on FST, it is possible to build a prototype layering module for in-line production of free-standing SI-targets, and the layering time, τform, does not exceed 30 s both for deuterium and deuterium-tritium fuel. Very short values of τform make it possible to obtain layers with a stable isotropic fuel structure to meet the requirements of implosion physics. [ABSTRACT FROM AUTHOR]

Realization of fusion energy imposes considerable challenges in the areas of producing cryogenic targets with an isotropic fuel structure and developing noncontact target delivery means. It was shown that the FST-layering method using high cooling rates (1â€"50 K sâˆ'1) and high-melting additives to fuel content (0.3%â€"25%) makes solid layers isotropic and free of local defects. FST-layering in line-moving shells is usually realized in a vertical single-spiral layering channel. Here we present our first results with a double-spiral layering channel (DS-LC). The cryogenic layers (D2 + 20% Ne) were formed in 5 shells (2 R ∼ 1.8 mm) during their rolling in the DS-LC, and then they were gravitationally injected to the test chamber at T = 5 K. The obtained isotropic layers (W ∼ 87 ÎĽ m) are stable in the temperature range from 5 K to T tp = 18.7 K of D2. The total layering time <20 s. Another critical issue is the noncontact target delivery. It is shown that using transport of high-temperature superconductors in the magnetic fields provides stable noncontact target acceleration placed in a superconducting sabot. The proof-of-principle experiments have shown that using only 1 field coil allows one to accelerate such sabot up to 1 m sâˆ'1. Computationally, it has been shown that acceleration up to a velocity of 200 m sâˆ'1 will require about 200 field coils (0.25 T each) along the 5 m-length of the linear accelerator with overloads a = 400 g; the velocity of 400 m sâˆ'1 will require the acceleration length of 20 m at the same a = 400 g. First steps are made to reduce the dimensions of the linear accelerator using a cyclic permanent magnet guideway with less than 10 field coils to achieve target injection velocities in the range of V inj = 200â€"400 m sâˆ'1. [ABSTRACT FROM AUTHOR]

The paper presents the results of mathematical and experimental modeling of in-line production of inertial fusion energy (IFE) targets of a reactor-scaled design. The technical approach is the free-standing target (FST) layering method in line-moving spherical shells. This includes each step of the fabrication and injection processes in the FST transmission line (FST-TL) considered as a potential solution of the problem of mass target manufacturing. Finely, we discuss the development strategy of the FST-TL creation seeking to develop commercial power production based on laser IFE. [ABSTRACT FROM AUTHOR]