"Technical Physics Letters"

Balachenkov, I. M.; Petrov, Yu. V.; Gusev, V. K.; Bakharev, N. N.; Bulanin, V. V.; Varfolomeev, V. I.; Zhil’tsov, N. S.; Kiselev, E. O.; Kurskiev, G. S.; Minaev, V. B.; Patrov, M. I.; Petrov, A. V.; Ponomarenko, A. M.; Sakharov, N. V.; Tel’nova, A. Yu.; Tokarev, V. A.; Khromov, N. A.; Shchegolev, P. B.; Yashin, A. Yu.

doi: 10.1134/S1063785020120032pmid: N/A

On the spherical tokamak Globus-M2 in discharges with toroidal magnetic field of 0.7 T by means of magnetic probes and a number of other diagnostics during neutral beam injection at the current ramp up stage, magnetic field oscillations in the range of 100–300 kHz having their frequency increasing in time, had been observed. Eigenmodes with wavenumbers n = 1–3 and m = 2–4 were being registered. These oscillations were identified as Alfvén cascades. By means of multi-channel fluctuation reflectometer, observed eigenmodes were found to be localized near the magnetic shear reversal radius. Application of MHD-spectroscopy technique allowed us to determine safety factor temporal evolution and experimental values are in well agreement with modelling results, provided by ASTRA transport code.

Ginzburg, N. S.; Yurovskiy, L. A.; Nazarovsky, A. V.; Sergeev, A. S.; Zotova, I. V.

doi: 10.1134/S1063785020120068pmid: N/A

We analyze the possibility of generating pulses of superradiance in the terahertz range during the concurrent scattering of a laser pulse by a high-current relativistic electron beam with frequency conversion downward. The scattered radiation propagates in the opposite direction (with respect to the translational velocity of the particles). When pulses with an energy of 3 kJ are used as a pump at a wavelength of ~1 μm and the laser pulse duration and the length of the interaction region are optimized, it is possible to generate pulses of scattered counterpropagating (for the translational velocity of particles) radiation with a power of approximately 580 kW and a duration of 30 ps at 100 μm.

Epoletov, V. S.; Marichev, A. E.; Pushnyi, B. V.; Salii, R. A.

doi: 10.1134/S1063785020120056pmid: N/A

Results are reported of using subcontact layers with energy gap width Eg of 0.35 to 0.8 eV for obtaining low-resistivity electrical contacts to p-InP. An experimental dependence of the contact resistance on Eg of the subcontact material InxGa1 –xAs was obtained.

Khlebnikova, Yu. V.; Suaridze, T. R.; Akshentsev, Yu. N.

doi: 10.1134/S106378502012010Xpmid: N/A

The quality of the crystallographic texture is analyzed for thin ribbons made of ternary Cu–40% Ni–Me (Me = Nb, Mo, or W) alloys, which are promising materials for epitaxial substrates. Optimal regimes of recrystallization annealing of ~100-μm-thick ribbons made of these alloys are determined, which provide perfect cubic texture with a fraction of {001}〈100〉 grains of more than 96%. The proposed alloys are paramagnetic at operating temperatures of a high-temperature superconductor and less expensive than the nickel ones; therefore, they may be an alternative to the Ni–4.8 at % W alloy, which is most popular in the production of ribbon substrates.

Davydov, S. Yu.; Lebedev, A. A.; Zubov, A. V.; Bulat, P. V.

doi: 10.1134/S1063785020120044pmid: N/A

Using simple models, analytical estimates of quantum capacitance CQ are obtained for an infinite sheet, a nanoribbon, and a chain of two-dimensional analogs of the ANB8 –N compounds with a hexagonal structure (graphene-like compounds). It is demonstrated that there is a nonmonotonic dependence of CQ on the electrostatic potential.

Ishchenko, A. N.; Burkin, V. V.; Diachkovskii, A. S.; Maistrenko, I. V.; Rogaev, K. S.; Sammel, A. Yu.; Chupashev, A. V.

doi: 10.1134/S1063785020120081pmid: N/A

Peculiarities of the motion of one and two supercavitating strikers in water upon their simultaneous entry into water at speeds exceeding the speed of sound in the medium are considered. Conditions have been developed to ensure nondestructive entry of strikers into the water and stable movement along an aiming trajectory in the transonic speed range. A stable joint motion of two strikers in water at supersonic speed is obtained.

Torgashov, R. A.

doi: 10.1134/S1063785020120147pmid: N/A

A novel planar microstrip meander-line slow-wave structure (SWS) on dielectric substrate for a miniature low-voltage millimeter-band traveling-wave tube (TWT) with a high-aspect-ratio sheet electron beam is proposed. Main electromagnetic parameters of the SWS were studied. Using of such a slow-wave structure may lead to increase of the gain and output power of the TWT amplifier.

Sycheva, A. A.

doi: 10.1134/S1063785020120135pmid: N/A

Molecular dynamics (MD) method was used to study 200 eV Ar ion impact on silicon nanoparticles of various sizes . Based on the MD simulations, the analysis of sputtering mechanisms and differences in the ion energy deposition which are determined by the curvature of the target surface, is performed in the paper.

Glazov, A. L.; Muratikov, K. L.

doi: 10.1134/S106378502012007Xpmid: N/A

The nature of changes in laser photoacoustic signals near small-diameter holes in aluminum and steel layers in a bimetallic plate obtained by hot rolling is investigated. The experimental results are compared with the solution of the classical Kirsch problem for stress distribution around a circular hole in a prestressed material. The possibility of estimating internal stresses by the laser photoacoustic method in combination with the method of drilling holes in industrial bimetallic plates is shown.

Bakhadirkhanov, M. K.; Isamov, S. B.; Ibodullaev, Sh. N.; Koveshnikov, S. V.; Norkulov, N.

doi: 10.1134/S1063785020120020pmid: N/A

It is shown that the photoresponse threshold and photosensitivity in a photoresistor material based on silicon doped with manganese atoms with the formation of the Mn4B nanoclusters can be changed by varying the electric field in the range of 0.1–30 V/cm. It has been found that, by changing the electric field, one can shift the photoresponse threshold of the samples at T = 100 K from 4.6 to 8 μm. The monochromatic photosensitivity at hν = 0.4 eV increases by 2.5 orders of magnitude as the field changes from 1 to 3 V/cm.