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The novel points of view to the formation of shaped charge jets are described. The physics of so-called hypercumulation are described in details and confirmed by numerical simulations. It has been shown that hypercumulation effects allow to increase both the speed and mass of a cumulative jets much more than the theory by LavrentyevBirkhoff predict. The applications of novel effects are the oil-well perforations.

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The control methods of cinematic parameters of cumulative plasma jets (PJ) formed while exposing conical targets to high-energy radiation are considered. It is shown that realization of the principle of the forced Jet formation allows to increase the speed and pulse of the formed PJ considerably.For obtaining of high speed plasma jets, acceleration of macro-particles to hypervelocity it is suggested in work El] to use the action of high energy radiation to the profiled targets.The idea can be developed in the following directions: introduction of the space radiation focusing, dynamic formation of the profiled (conical) target and realization of the principle of the forced jet formation fox the increase of energetic and speed parameters of plasma Jets.While Jet formation at the collapse of the profiled (e.g.conical) targets we deal w i t h the processes taking place in cumdative charges 121. At the same time we have a number of characteristic features while loading the target surface by means of high-energy radiation action: the loading speeds of the generating line, of the target pressure on its surface and dynamics of the target loading differ considerably. The first two differences are evident and the third difference is in the fact that while using the pulse systems the loading o f the generating line of the target occurs not with a terminal speed, but practically unstantaneously and the pulse and pressure are distributed along the target surface uniformly. It is possible to control the cinematic parameters of the formed PJ by introducing radiation focusing (for example, laser radiation focusing) along the generating line of target. It is possible to show that the distribution of the ablatian pressure along the generating line of the target should be close to linear, incident to the cone base In order to provide the maximum speed of the PJ. Such radiation focusing can be provided by means of special efements of diffiaction optics and quasioptics 131 allowing to concentrate the incident radiation along the arbitrary 3D conf!guration. So, for focusing "into cone" the structure of zones on the surface of a flat diffraction element should be described by the expression:where w = k / sin@) + Q k -l),(a)/(ctg(a)+ctg(P), 0 -the semiangle of the cone, f -a focal distance, hradiation wavelength. The shape of the focusing region of such an element in (ZJ) coordinates simulating in computer complex [4], is shown in the Figure 1 , t = 1 / sin(a), w Fig.la. Laser radiation focusing "into cone".Fig.1 b. T h e scheme of PJ formation. 1 -Laser, 2 -DOE, 3 conical target.2. The application of conical targets is connected with some technological difficulties stipulated by small dimensions of the target. It is possible to do away with strict requirements to geometric sizes reverting to a flat target and to transfer all the difficulties to the devices of radiation focusing. In other words, for rather thin target it is possible to make such density distribution of the 0-7803-8943-3/05/%20.00 0 2005 IEEE Natural Sciences

Basic physical problems of jet formation process on the basis of Lavrentiev-Birkhoff classical scheme are analyzed. It is shown that in process of realization of hypercumulation conditions for jet formation without complete stagnation point involving formation of the inner zone of constant pressure (dead zone), the flow mass is always greater than slug mass, that is unachievable in the known models. Smoothing effect of this zone on the development of different types disturbances, particularly, smoothing Rayleigh-Taylor instability for thin liner may be expected and shown in simulations.