Pinch-Effect in Laser Produced Plasma
Pinch-Effect in Laser Produced Plasma
Tech Area / Field
- FUS-PLA/Plasma Physics/Fusion
8 Project completed
Senior Project Manager
Malakhov Yu I
Central Research Institute of Machine Building (TsNIIMash), Russia, Moscow reg., Korolev
- Kurchatov Research Center, Russia, Moscow
- Technische Universität Darmstadt, Germany, Darmstadt\nCEA / DSM / Département de Recherche sur l'Etat Condencé, les Atomes et les Molécules / Service des Photons, Atomes et les Molecules, France, Gif-sur-Yvette Cedex\nUniversité de Provence / Centre Saint Jerome, France, Marseille\nUniversité de Paris VI / Laboratoire pour l'Utilisation des Lasers Intenses (LULI) / Laboratoire de Physique Atomique dans les Plasmas Denses, France, Paris
Project summaryThe investigation of the pinch-effect in laser plasmas produced at the irradiation of solid targets by an ultra-short (~ 10-12 s) laser pulse with the peak intensity more than 1018 W/cm2 presents the natural continuation of the previous investigations of the pinching current plasmas.
The remarkable peculiarities of sub-picosecond laser plasmas are:
1. High electron number density – up to atomic number density in solids and higher.
2. Generation of spontaneous quasi-static super-strong magnetic fields; magnetic induction up to 500 MG had been measured in recent experiments.
3. Production of jets of charged particles with high kinetic energy that are responsible for generation of magnetic fields; electrons with kinetic energy up to 100 MeV are observed at the laser intensity ~ 1020 W/cm2.
These peculiarities of overdense laser plasmas result in great perspectives of such an approach for investigation of the pinch-effect under the qualitatively new conditions of its realization and higher values of above parameters. New physical effects appear in laser plasmas when the peak laser intensity is higher than the relativistic values of Il2 > 1.4ґ1018 W/cm2mm2. The laser pulse with such intensities generates currents of high density that produce magnetic fields with the magnetic induction of 100 MG. Quasi-static magnetic fields of the relativistic laser plasmas are of the great importance in the evolution both of atomic and plasma processes.
Production of high-energy electrons confirms the pinch-effect in laser plasmas when the magnetic field exceeds the threshold value. High values of magnetic induction provide the development of this process even under the conditions of solid densities, i.e. at the high values of the kinetic pressure. The condition of its equilibrium is well known as the Bennett condition in the classical theory of pinch-effect. In the case of laser plasmas modified form of the Bennett condition connects the laser intensity with the number density of particles, since the value of the magnetic induction produced in plasmas depends on the intensity of laser radiation.
Pinch-effect is developing when the laser intensity exceeds the threshold value. Its investigation is of a great fundamental and practical interest since it is the key process in sub-picosecond laser plasmas at relativistic intensities. This is related with the atomic and nuclear processes in plasmas in the pinch region. Generation of fast electrons and production of plasma channels is surrounding by acceleration of atomic ions up to ~ 1 MeV. Interaction of electrons and atomic ions with the target matter results in generation of X-ray, g-radiation and various nuclear and photo-nuclear reactions. Realization of pinch phenomenon as a collapse of vortex structures leads to local increasing of plasma density and temperature and, hence, to increase of yields of nuclear reactions during their duration time. Scale and lifetime of such vortex structures exceed significantly the duration of the laser pulse and they are determined by slower dissipative processes.
Experimental investigation of above phenomena is of a great interest for determination of conditions for realization of principally new energetic technologies.
The goals of our Project are:
1. Development of theoretical models of pinch-effect produced by anisotropic pressure at the ionization of atoms in sub-picosecond relativistic laser plasmas;
2. Experimental investigations of pinch-effect in picosecond laser plasmas at the laser intensity of 1018 – 1019 W/cm2, pulse duration of ~ 1 ps and the wavelength of 1 mm;
3. Elaboration of basics of new energetic technologies using pinch-effect in relativistic laser plasmas.
The competence of the participants of this proposal in the above cited investigations is based on the great experience of the previous investigations of dynamics of laser plasmas as well as of atomic and nuclear processes in laser plasmas. Central Research Institute of Machine Building has the experimental setup where the goals of this project can be realized.
Expecting results and their applications. This proposal refers to the category of the fundamental investigations. New results are expected during its realization:
1. Finding of the criteria of similarity for pinching structures in current and laser plasmas. Derivation of parameters required for appearance and development of stability of plasma structures responsible for pinch-effect in laser plasmas.
2. Theoretical model of the pinch-effect in solid state plasmas produced by relativistic laser radiation.
3. Derivation of parameters of atomic and nuclear processes and their optimization with respect to yield and parameters of particle jets (electrons, atomic ions, neutrons, alpha-particles), X-ray and g-radiation under the conditions of pinch-effect in laser plasmas.
4. Calculating parameters and results of optimization of energetic processes in pinch-structures of laser plasmas.
5. Modernization of the laser setup with the achievement of relativistic parameters of the radiation: the laser intensity of 1018 – 1019 W/cm2, pulse duration of ~ 1 ps and the wavelength of 1 mm.
6. The investigation methods developed on this laser setup (including multi-channel methods) for spectral, angular and energy distributions of neutron, X-ray, g-radiation and jets of charged particles produced in overdense relativistic laser plasmas.
7. Experimental results for determination of optimal conditions of pinch-effect in picosecond laser plasmas, namely, parameters of laser radiation, the experimental geometry, material and structure of the target.
8. Recommendations on applications of pinch-effect for increasing of the yield of nuclear reactions, including the fusion reactions with high ignition temperature.
9. Recommendations on creation of new atomic and nuclear technologies using pinch-effect in laser plasmas.
These expected results will supplement significantly today knowledge about physics of interaction between relativistic laser radiation and a matter, and allow to investigate new approaches to the diagnostics of processes inside the laser focus, and also to develop the suggestions for creation of new energetic technologies. Their principal elements are:
1. Elaboration of recommendations for creation of short-pulse source of relativistic electrons with the energy more than 100 MeV, the monochromatic source of fast neutrons and the short-pulse of soft and hard X-ray.
2. Elaboration of recommendations for using of pinch-effect with respect to increasing of the yield of nuclear reactions in laser plasmas.
Realization of goals and tasks of ISTC. The principal goals and tasks described in the Agreement about the institution and Charter of ISTC will be realized in the process of project fulfillment, namely:
1. The possibility to use their abilities in the elaboration of peaceful fundamental scientific problems will be leaved to the scientists which previously were busied in elaboration of the war rocket-space technology and nuclear weapons in Russia.
2. The additional possibilities of integration into the international scientific society via exchange by results of investigations, participation in the International conferences, meeting and seminars with the participation of the specialists of the leading foreign scientific centers will be leaved to these scientists.
3. The support for the fundamental investigations and creation of principal new ecology clear energetic technologies will be provided.
4. The assistance to the solution of both the national and international technical problem – creation and production of new ecology clear energy sources and technology for their using will be provided.
The volume of work. The work in this project includes theoretical (including numerical) calculations and experimental investigations as well as the creation of recommendations for production of new energetic technologies. The content of work is determined by the solution of the several tasks:
1. The development of the theoretical model of pinch-effect in overdense relativistic laser plasmas.
2. The modeling of atomic and nuclear processes in the magnetized pinching laser plasmas.
3. The investigation of energetic processes inside pinching structures in laser plasmas.
1. Modernization of the laser setup with the increasing of the peak laser intensity up to ~ 1019 W/cm2 and completing of the control methods for parameters of laser radiation.
2. The development of experimental methods for observation of the anisotropy in neutron, X-ray, g-radiation and jets of charged particles in order to investigate pinch-effect in laser picosecond plasmas.
3. Experimental investigations devoted to optimization of the appearing of the pinch-effect in picosecond laser plasmas with respect to parameters of laser radiation, experimental geometry, material and structure of targets.
4. Experimental investigations of the nuclear fusion reactions including reactions with the ignition temperature more than 100 keV in picosecond laser plasmas.
The functions of foreign collaborators consist of the exchange by information during the realization of the project, of the connection between the participants of this project and foreign institutions and scientists, which are interested for investigations in this branch, of comparison of obtained results with results of foreign centers, and finally of checking and confirmation of discovered effects and reliability of suggested approaches upon experimental setups of foreign centers, as well as organization of further investigations within the frames of common projects and programs.
The technical approach and methodology of the project provides using of the modern theoretical and experimental methods for investigation of atomic and nuclear processes at the pinch creation in laser plasmas. The theory of these processes will be created on the base of approaches developed during the fulfillment of the previous ISTC projects ## 0856 and 2155 and also on the base of methodology developed in “Kurchatov Institute” and scientific works of the participants of those projects. Experimental model investigations provide works on laser setup equipped by the diagnostic complex for observation of atomic and nuclear processes in laser plasmas.
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