Preparation of High-Purity Silicon Tetrafluoride by Thermal Dissociation of Na2SiF6

The possibility of preparing high-purity silicon tetrafluoride by the thermal dissociation of pure grade Na₂SiF₆ was studied. The impurity composition of the product was studied by IR and atomic emission spectroscopy and by mass spectrometry.     

On rational approximation of convex functions with a given modulus of continuity

Доказывается, что для наименьших равномер ных рациональных уклоне нийR _n(f) выпуклой на [0,1] функции с модулем непрерывно сти, не превосходящемω(δ), сп раведлива оценка $$R_n (f) \leqq c\frac{{\ln ^2 n}}{{n^2 }}\mathop {\max }\limits_{e^{ - n} \leqq \theta< 1} \left\{ {\omega (\theta )\ln \frac{1}{\theta }} \right\},$$ гдес — абсолютная по стоянная.     

High-energy ions from near-critical density plasmas via magnetic vortex acceleration

Ultraintense laser pulses propagating in near-critical density plasmas generate magnetic dipole vortex structures. In the region of decreasing plasma density, the vortex expands both in forward and lateral directions. The magnetic field pressure pushes electrons and ions to form a density jump along the vortex axis and induces a longitudinal electric field. This structure moves together with the expanding dipole vortex. The background ions located ahead of the electric field are accelerated to high energies. The energy scaling of ions generated by this magnetic vortex acceleration mechanism is derived and corroborated using particle-in-cell simulations.     

Observation of magnetized soliton remnants in the wake of intense laser pulse propagation through plasmas

Slowly evolving, regularly spaced patterns have been observed in proton projection images of plasma channels drilled by intense (?101? W?cm?2) short (～1 ps) laser pulses propagating in an ionized gas jet. The nature and geometry of the electromagnetic fields generating such patterns have been inferred by simulating the laser-plasma interaction and the following plasma evolution with a two-dimensional particle-in-cell code and the probe proton deflections by particle tracing. The analysis suggests the formation of rows of magnetized soliton remnants, with a quasistatic magnetic field associated with vortexlike electron currents resembling those of magnetic vortices.     

Fundamental processes in relativistic laser plasmas

A review is given of processes fundamental for current relativistic regimes of laser matter interaction such as the generation and evolution of relativistic coherent nonlinear electromagnetic structures; generation of extremely high intensity electromagnetic waves and extremely high energy charged particle beams; novel regimes of electromagnetic wave interaction with matter and of the prospects for using laser accelerators for the high energy physics and for the laboratory relativistic astrophysics with relativistic laser plasmas.     

Plasma ion evolution in the wake of a high-intensity ultrashort laser pulse

Experimental investigations of the late-time ion structures formed in the wake of an ultrashort, intense laser pulse propagating in a tenuous plasma have been performed using the proton imaging technique. The pattern found in the wake of the laser pulse shows unexpectedly regular modulations inside a long, finite width channel. On the basis of extensive particle in cell simulations of the plasma evolution in the wake of the pulse, we interpret this pattern as due to ion modulations developed during a two-stream instability excited by the return electric current generated by the wakefield.     

A conceptual design of a power-supply system of deflecting plates for multivariate injection into the NICA accelerator complex booster

The design of the complex envisions the installation of three pairs of electric deflecting plates in the booster ring. These plates are designed to carry out the ion-beam injection into the booster in regimes of single-turn, multiturn, and multiple injection. We present a feasible scheme of a power-supply circuit that allows for all the prospective injection regimes through independent unipolar charging and discharging of the plates.