MODELS, METHODS, AND TECHNOLOGIES FOR CALCULATION OF CHARACTERISTICS OF THE PHYSICAL FACILITY URAGAN-2M

Models, methods, and algorithms for three-dimensional modeling of the screw winding of the Uragan-2M torsa-tron are considered. The application of the method of kinematic modeling is substantiated as the most acceptable for obtaining solid-state and surface models of elements of a magnetic system. Methods for calculating the stresses and strains arising in the elements of the magnetic system of a screw winding under the influence of ponderomotive forces are presented, which makes it possible to determine the strength of the structural elements of the facility.

Ponderomotive Forces in the System of Two Nanoparticles

Mechanical consequences of electromagnetic interaction of two nanoparticles have been studied theoretically. It has been shown that local field enhancement effect, which causes appearance of the local field gradients, can lead to ponderomotive forces acting on the nanoparticles. Distribution of the local field in the system has been calculated and ponderomotive forces directions and values were evaluated. It has been shown that in the system of two different-sized nanoparticles the forces act mainly on the surface of bigger nanoparticle and for some systems its value may acquire up to several tens of nanonewtons. Possible application of the results to study of biological systems has been also discussed.

Control of the Properties of Welded Joints in Wet Underwater Welding

The aquatic environment will negatively affect the processes that occur during the formation of a welded joint and leads to a deterioration in its properties. The welding conditions do not allow the use of traditional methods to improve the quality of the weld metal - preheating or subsequent heat treatment. One of the possible effective ways to solve this problem when welding with flux-cored wire is the use of external electromagnetic exposure. Generation of axial alternating control magnetic fields in the welding zone allows controlling the hydrodynamics of the molten weld pool. Because of the interaction of an external electromagnetic field with an electric field of the arc, ponderomotive forces appear in the weld pool, which leads to mixing of the liquid metal. Changing the direction of electromagnetic induction with a given frequency and interval, you can periodically change the direction of flow in the weld pool. Intensive reverse mixing of the melt occurs, during which the hydrogen accumulated in front of the crystallization front as a result of concentration compaction is removed from it, the melt temperature in the central and peripheral areas of the pool is averaged, which slightly reduces the crystallization rate of the weld pool, thereby increasing its degassing time. As a result, it was possible to significantly reduce the porosity of the weld metal (more than 8 times) and reduce the hydrogen content (more than 2.5 times). Metallographic studies showed a significant refinement of the structure both weld metal and the heat-affected zone (2 and 1.3 times, respectively), its homogenization and a decrease in the degree of defectiveness. Thus, the investigations showed that the external electromagnetic effect on the liquid metal pool in the process of wet welding underwater is a useful tool that allows you to control the processes that occur during the crystallization stage of the weld pool and significantly increase the ductility of the weld metal (more than 1.5 times).

Investigating the Origin of the First Ionization Potential Effect With a Shell Turbulence Model

The enrichment of coronal loops and the slow solar wind with elements that have low First Ionization Potential, known as the FIP effect, has often been interpreted as the tracer of a common origin. A current explanation for this FIP fractionation rests on the influence of ponderomotive forces and turbulent mixing acting at the top of the chromosphere. The implied wave transport and turbulence mechanisms are also key to wave-driven coronal heating and solar wind acceleration models. This work makes use of a shell turbulence model run on open and closed magnetic field lines of the solar corona to investigate with a unified approach the influence of magnetic topology, turbulence amplitude and dissipation on the FIP fractionation. We try in particular to assess whether there is a clear distinction between the FIP effect on closed and open field regions.

Charged particle guiding and beam splitting with auto-ponderomotive potentials on a chip

Electron and ion beams are indispensable tools in numerous fields of science and technology, ranging from radiation therapy to microscopy and lithography. Advanced beam control facilitates new functionalities. Here, we report the guiding and splitting of charged particle beams using ponderomotive forces created by the motion of charged particles through electrostatic optics printed on planar substrates. Shape and strength of the potential can be locally tailored by the lithographically produced electrodes’ layout and the applied voltages, enabling the control of charged particle beams within precisely engineered effective potentials. We demonstrate guiding of electrons and ions for a large range of energies (from 20 to 5000 eV) and masses (from 5 · 10−4 to 131 atomic mass units) as well as electron beam splitting for energies up to the keV regime as a proof-of-concept for more complex beam manipulation.

Electrostrictive polymer plates as electro-elastic material surfaces: Modeling, analysis, and simulation

In this article we discuss modeling of electrostrictive polymer plates as electro-elastic material surfaces. A complete direct approach is developed without the need to involve the three-dimensional formulation. Ponderomotive forces and couples as well as constitutive coupling by means of electrostriction are accounted for. We propose a rational formulation for the augmented free energy of electro-elastic material surfaces incorporating electrostriction by a multiplicative decomposition of the surface stretch tensor and an additive decomposition of the surface curvature tensor into elastic and electrical parts. Numerical results computed within the framework of this complete direct approach are compared to results computed with a method that requires the numerical integration of the three-dimensional augmented free energy through the thickness of the plate and to alternative formulations reported in the literature.