New solutions for target delivery systems are essential for advanced inertial fusion energy (IFE) laser facilities. Original target delivery concept based on magnetic levitation (MAGLEV) technology has been proposed at the Lebedev Physical Institute (LPI). The operational principle is the quantum levitation of Type-II, high-temperature superconductors (HTSC) in gradient magnetic fields. In doing so, a cryogenic target is placed inside a levitating HTSC-sabot, which is accelerated above a permanent magnet guideway system. In this paper, we continue our researches on building a cyclotron accelerator with a limited magnetic track for noncontact target delivery. The target sabot models were made from second-generation high-temperature superconductor (2G-HTSC) tapes with a J-PI-04-20Ag-20 Cu structure and high vortex pinning to ensure levitation stability of the acceleration process. Careful execution of demo experiments (T 80 K) clarify that the HTSC-sabot runs stably above the circular track during its acceleration. The calculation and experimental results are in a good agreement at T 80 K, which allows estimating the running performance of the cyclotron accelerator at operating temperature T 17 K. The estimations have shown that for magnetic fields В 2 T with induction gradients ∂B2/∂x 2 × 102 T2/m, the cyclotron accelerator with a radius of 4 m can overcome the target injection velocity v_inj = 200 m/s at a = 1000g, which is the lower limit for future IFE power plant. For existing laser facilities the velocities 20‒100 m/s can be easily reached for a more comfortable acceleration range a = 10‒250g. In addition, the article discusses promising research at the LPI in the field of cyclotron acceleration, both from the point of view of selecting new HTSC materials and improving the design of HTSC-sabots. The obtained results provide the design reference for building the higher-performance cyclotron accelerators for IFE.

Magnetic levitation technologies are studied as an innovative basis for developing contactless systems for delivering cryogenic targets to the laser focus of an ICF facility or future power plant. A necessary element of such systems is a special target carrier made of high-temperature superconductors (HTSC) with high vortex pinning. It is shown experimentally that an HTSC carrier in the form of an outer coating of the target makes it possible to completely eliminate mechanical friction during target acceleration due to its levitation in gradient magnetic fields. The prospects for further development of this direction in the area of creating HTSC nanostructured films and coatings are discussed.

Creation of an efficient system for the frequent delivery of cryogenic fuel targets (CFT) to the focus of a powerful laser facility is one of the key directions of research in inertial confinement fusion (ICF). The paper discusses prospects for the creation of a ring magnetic system based on the contactless acceleration of a levitating CFT carrier made of high-temperature type II superconductors (HTSC), up to specified injection velocities of 200–400 m/s. For this purpose, the temperature dependence of the magnetic moment of HTSC tapes in the range Δ T = 10–92 K was studied, prototype experiments on the acceleration of HTSC carriers at T ~ 80 K due to an external action on them with a frequency of ~1 Hz were carried out, and the speed for the stall of HTSC carriers from a circular trajectory were calculated. The calculation results are in good agreement with the experiment, which makes it possible to estimate the parameters of the ring magnetic accelerator for the operating temperature of the CFT injector T ~ 17 K. It is shown that the method proposed is promising for the creation of systems for noncontact delivery of CFT based on the principles of levitation and subsequent injection of CFTs into the center of the ICF reactor chamber at the required speed. The results of planning a new series of experiments are presented: acceleration of an HTSC carrier followed by injection of a surrogate target into the chamber of the GARPUN (LPI) KrF laser.

Creation of a delivery system based on noncontact positioning and transport of the cryogenic fuel targets represents one of the major tasks in a general program of inertial fusion energy (IFE) research. The purpose is to maintain the fuel layer quality during acceleration and injection of IFE targets at the focus of a powerful laser facility or IFE reactor. The program of the Lebedev Physical Institute (LPI) includes much development work on creation of different designs of the hybrid accelerators for IFE target transport with levitation. One of the main directions is an electromagnetic accelerator (EM-AC) + PMG system, where PMG is the permanent magnet guideway. The operational principle is based on quantum levitation of type-II high-temperature superconductors (HTSC) in the magnetic field. At the current stage, conceptual development of "EM-AC + PMG" hybrid accelerator is complete, and proof-of-principle experiments in mutually normal magnetic fields are made. This accelerator is a combination of the acceleration system (field coils generating the traveling magnetic waves) and the levitation system (PMG including a magnetic rail or magnetic track). The results obtained show that the HTSCs can be successfully used to maintain friction-free motion of HTSC sabots over the PMG, and also provide the required stability of the levitation height over the whole acceleration length due to the pinning effect. Additionally, using the driving body from MgB2 superconducting coils as a sabot component (critical current 5,000 A at magnetic induction 0.25 T) allows one to reach injection velocities of 200 m/s under 400 g at 5 m acceleration length.

A central element of a power plant based on inertial confinement fusion (ICF) is a target with cryogenic hydrogen fuel that should be delivered to the center of a reactor chamber with a high accuracy and repetition rate. Therefore, a cryogenic target factory (CTF) is an integral part of any ICF reactor. A promising way to solve this problem consists in the FST layering method developed at the Lebedev Physical Institute (LPI). This method (rapid fuel layering inside moving free-standing targets) is unique, having no analogs in the world. The further development of FST-layering technologies is implemented in the scope of the LPI program for the creation of a modular CTF and commercialization of the obtained results. In this report, we discuss our concept of CTF (CTF-LPI) that exhibits the following distinctive features: using a FST-layering technology for the elaboration of an in-line production of cryogenic targets, using an effect of quantum levitation of high-temperature superconductors (HTSCs) in magnetic field for noncontacting manipulation, transport, and positioning of the free-standing cryogenic targets, as well as in using a Fourier holography technique for an on-line characterization and tracking of the targets flying into the reactor chamber. The results of original experimental and theoretical investigations performed at LPI indicate that the existing and developing target fabrication capabilities and technologies can be applied to ICF target production. The unique scientific, engineering, and technological base developed in Russia at LPI allows one to make a CTFLPI prototype for mass production of targets and delivery thereof at the required velocity into the ICF reactor chamber.

1 Федеральное государственное бюджетное учреждение науки Физический институт им.П.Н.Лебедева Российской академии наук, Москва, Россия 2 Национальный исследовательский ядерный университет «МИФИ», Москва, Россия 3 ООО «ЦЭ Интер РАО ЕЭС», Москва

The target factory of an Inertial Fusion Energy (IFE) power plant (or reactor) must supply the targets with a rate of 1-10 Hz including their injection and transport through the chamber.HiPER is a proposed European High Power laser Energy Research facility dedicated to demonstrate the feasibility of laser driven fusion for IFE reactor. The work of HiPER facility requires formation & delivery of cryogenic free-standing targets with a rate of more than 1 Hz.To meet these requirements, an approach to fuel layering based on conduction cooling of a batch of moving spherical targets has been developed at the Lebedev Physical Institute (LPI). The approach demands to use free-standing targets in each production step: fuel filling, fuel layering, target characterization and injection.In this report, the expert results on the development of a specialized layering module prototype for a high reprate FST formation of HiPER cryogenic targets are presented.

Cylindrical cryogenic targets are required to carry out the Laboratory Planetary Science scheme of the experiments of the High Energy Density matter Generated by Heavy Ion Beams collaboration at FAIR. In this paper, for the first time a thorough analysis of the problem of such targets' fabrication, delivery and positioning in the center of the experimental chamber has been made. Particular attention is paid to the issue of a specialized cryogenic system creation intended for rep-rate supply of the High Energy Density matter Generated by Heavy Ion Beams experiments with the cylindrical cryogenic targets.

A method of ICF targets parameters reconstruction from the set of backlit shadowgraph images was developed. Proposed approach can be used for nondestructive inner (DT ice in the case of cryotarget) surface quality characterization of single- and double- layered targets and shells.Previously designed computer 3D ray-tracing model allowed us to carry out detailed investigation of the target shadowgraph image formation, to localize rays forming bright ring and to infer analytical description of this rays' group. Having been guided by this experience we designed an algorithm of inner surface shape determination using bright ring location on target's image and developed corresponding software package.This package provides a wide set of image processing tools: both general processing (pointwise operations, spatial filtering, maximums and edges localization, etc) and specific methods (3D reconstruction, inner and outer surfaces RMS and power spectra estimation, results' visualization in different forms, etc).Proposed method and its software implementation were tested using two kinds of image sets - set of backlit photographs of real one-layered shells and set of digitally synthesized shadowgraph images.

We present our results on developing a diagnostic complex for high-precision characterization of the parameters of laser-fusion microobjects, such as microspheres and cryogenic targets (the microobject size is 1–2 mm). The complex operates based on the principle of tomography. The complex consists of (a) the scanning system providing a set of shadow projections of a microobject in the visible range of radiation and (b) specially developed software for 3D reconstruction of the microobject from the set of projections. The spatial resolution of the optical system is 1 µm for a probing-radiation wavelength of 490 nm. The distinctive features of the diagnostic complex are (1) operation with both free-standing and mounted targets and (2) the possibility of scanning the targets from room to cryogenic temperatures. The operation of the complex was demonstrated in the reconstruction of polystyrene microspheres by a large set (80–90) of shadow projections at room and cryogenic temperatures.

In recent years, research into the development of reliable methods and techniques for characterization and quality control of ICF/IFE targets has been carried out very actively. This is motivated by the need to provide the means for precise and accurate knowledge of cryogenic target parameters. On the other hand, particular emphasis should be paid to the fact that fuelling of a commercial power plant requires similar to 6 targets each second. This indicates that the development of fast quality control techniques is of critical importance as well. Therefore, in this report we discuss the issues underlying the construction of different algorithms for characterization and quality control of ICF/IFE targets. Among them are: (a) algorithm banks and their structure, (b) algorithm testing, (c) target reconstruction experiments. The algorithm bank incorporates the algorithms for two stages of target production: the stage of fuel layering technique development (motionless target) and the stage of cryogenic target delivery (injected target). In the first case an inverse algorithm for individual target characterization (3D target reconstruction) and two threshold algorithms for fast control of target quality are presented. They are based on tomographic information processing methods. Experimentally, tomographic data acquisition is carried out by a hundred projections microtomograph. The spatial resolution of the optical system of the microtomograph is 1 mu m for 490 nm wavelength, the accuracy of target angular positioning is +/-1.5-2.5 min. In the second case we describe the algorithm based on Fourier transform holography for ultra fast target characterization during its injection. The performed computer experiments have demonstrated much promise of this approach in the following directions: recognition of the target imperfections in both low- and high-harmonics; quality control of both a single target and a target batch; simultaneous control of both an injected target quality and its velocity and trajectory.

We present a summary of the techniques used to produce hollow plastic microshells from solid polymer granules using drop tower techniques. Unlike solution drop tower techniques, the use of these granules allows one to produce good quality shells with diameters of 1 to 1.5 mm. The reasons for hollow plastic shell diameter limitations are discussed, and based on these studies we present a new drop tower furnace concept we call a ballistic furnace that has been designed to produce large (2 to 3 mm) polystyrene shells. The characteristics of the individual components such as the pellet injector and the fast cooling system are given.

An investigation was made of the problem of fabrication of targets for thermonuclear fusion. Experience with methods for the fabrication of large single-shell and multishell targets demonstrated that targets of the size needed for thermonuclear reactors should not be complicated or expensive. Investigations were made of the processes involved in the formation of hydrogen isotope layers in cryogenic targets. A unit for the fabrication, storage, and delivery of cryotargets to a laser focus (known as the cryogun) was proposed and tested.

Generation of DD neutrons in the experiments on heating and compression of high-aspect fusion pellets in the Del'fin-1 facility, I V Aleksandrova, N G Basov, B L Vasin, A A Galichiĭ, A E Danilov, A I Isakov, M P Kalashnikov, M V Kirillov-Ugryumov, V V Kushin, V M Kolobashkin, B V Kruglov, V K Lyapidevskiĭ, M Yu Mazur, A M Maksimchuk, Yu A Merkul'ev, Yu A Mikhaĭlov, A I Nikitenko, F A Nikolaev, Viktor V Orlov, V P Osetrov, V A Prorvich, V N Puzyrev, A V Rode, S M Savchenko, A V Sartori, G V Sklizkov, O I Stukov, S I Fedotov, A L Khitrov