As distinct from numerous papers where the problem of the electron thermal conductivity limitation is considered to be a consequence of arising plasma turbulence this paper deals with a "classic mechanism" of limitations. It has been shown that the above-mentioned limitation follows from the condition of the plasma quasi neutrality conservation on the absorption area near the surface of a target irradiated by a laser pulse, where the electron density is critical for the given laser wave length. The thermal conductivity limitation which is discussed below complies with experimental data.
As is known in literature are discussed the number of methods of high power EUV sources creation for EUV lithography including laser application, micro pinch, plasma focus, capillary discharge etc. The aim of this paper is to find the optimal physical conditions in plasma as EUV source taking into account, before all, the kinetics an transfer of light quantum. It is shown that the efficiency of plasma EUV source depends, in the main, on material of target, density of electrons and their temperature. In conclusion a variant of creating an alternative ("linear") EUV source on the basis of self-compression of plasma shells in the regime of slow energy input is considered.
In the experiments on the CO2-laser facility TIR with output pulse duration ~15 ns and pulse energy ~100 J high-current beams of ions with charge Z~20 ÷ 30 and energy up to ~1 MeV were obtained. High quality of spatial and temporal light beam characteristics as well as possibility to vary its parameters in accordance with required target irradiation conditions provide an opportunity for generation of ion beams with high charge and large number of particles. Results of measurements of ion energy spectra and ion fluxes for different expansion angles are presented. Technological and medical applications of such beams are discussed.
The problem of producing fast ion plasma fluxes on laser irradiation of a target with atomic number Z0>1 in a strong magnetic field is considered. It is shown that the energy of multiply charged ions in the plasma fluxes can achieve high values of the order of 1 MeV at relatively low temperatures of the order 3-5 keV in the plasma corona where the Pekle number Pe>>1. The flux intensity grows with rising a total radiation power, depends on the laser wavelength and attains values of the order of several mega amperes when the target irradiated with CO2-laser pulse with a relatively moderate power of the order of 10 TW.
A brief analytical review of basic data obtained in theoretical and experiments into the process of acceleration of solid bodies by a laser pulse in a mode of laser ablation in presented. It is noted the possibilities of laser acceleration methods have not been exposed yet. This can be ascribed to a great variety of physical conditions of acceleration by use of laser ablation depending on the problem stated and approach to its realization including the choice of material for ablation, type of laser facility, laser beam intensity and so on. The paper deals with the following: data on flat foil acceleration by a nanosecond laser pulse; conditions of accelerating frozen hydrogen pellets by a CO2-laser pulse in the regime of laser driven rocket thrust; and possibilities of launching satellites into low-altitude earth orbits by use of high- power lasers. Optimal physical conditions in a laser plasma corona (vapours near the surface irradiated) which enable the best results to be reached are discussed.
A problem of accelerating pellets of significant mass with a CO2-laser pulse (or a pulse train) is under consideration. As it is known, the highest magnitudes of the accelerated pellet velocity of about 100 km/s were observed in the experiments on accelerating flat foils with a nanosecond Nd-laser pulse. The acceleration efficiency achieved was 5 - 10%. However the accelerated target usually turned into a cloud of superdense low-temperature plasma in these experiments. To avoid pellet destruction and to achieve maximum acceleration it is necessary, depending on the task stated, to meet certain requirements to the laser wave-length, power density and pulse duration. So, for instance, to accelerate pellets of frozen hydrogen only long-wave lasers can be used. When pellets of other materials are to be accelerated the wave length range used can be broadened. However, the laser pulse duration must be large enough to avoid shock wave formation. The regime of laser-driven rocket traction seems to be the most acceptable. Difficulties in attaining this regime in the experiment mainly concern formation of a uniform and extended in the atmosphere laser beam. Acceleration of frozen hydrogen pellets for fuel injection in thermo-nuclear setups with magnetic confinement are discussed. It is shown that on the basis of laboratory CO2-lasers available pellet velocities up to 10 - 100 km/s can be obtained.
The possibility of creating magnetic configurations with improved confinement based on the laser ablation of a pellet of frozen hydrogen is considered. The advantageous characteristic of the proposed laser methods is that they allow a local control of the plasma parameters and magnetic field. To solve the above problems, a frozen-hydrogen pellet is injected into the plasma volume and irradiated by laser pulse. As a result of mutual diffusion of laser plasma and magnetic field, some profiles of plasma density and magnetic configuration are realized. It is shown that quasi- stationary equilibrium states of tokamak plasma column sustained by the uninterrupted fuel feeding ca be constructed. It is found that specified profiles of plasma density and magnetic field can be provided by using some plasma particles source whose intensity is determined by the laser flux density.