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•T-15MD project is the initial technical base for creating fusion neutron source for atomic energy needs.•The preassembly of the tokamak T-15MD magnet system together with the vacuum ...vessel was completed.•Most of tokamak systems were manufactured and preliminary tested before the final assembly of tokamak.•All the diagnostic equipment is available and part of it was used in experiments on tokamak T-10.•Physical start-up T-15MD is scheduled for December 2020 year.
At the present time, in the NRC Kurchatov Institute under the auspices of the Federal Target Program “Nuclear energy-technologies of new generation for period 2010–2015 and to the prospect until 2020” the tokamak T-15MD and supporting facilities are being built. The preassembly of the tokamak T-15MD magnet system together with the vacuum vessel was completed at a plant in Bryansk. All elements of the magnet system and vacuum vessel have been delivered to the NRC “Kurchatov Institute” in Moscow for the tokamak T-15MD assembly. It is expected that the T-15MD assembly will be completed in March of 2019. The reconstruction of the sub-station 110/10/04 kV for own needs was completed in 2017 and the reconstruction of the main sub-station 110/10/1 kV, 300 MW was completed in 2018. Twenty- two of the new transformers 10/1 kV and 20 new thyristor convertors will be installed during 2018–2019 period. One gyrotron with output power 1 MW for pre-ionization should be installed in 2019. Tokamak T-15MD connection to water and electrical communication and also the adjustment of control system will be completed in the middle of 2020. Physical start-up T-15MD is scheduled for December 2020 year.
In-plane hole g factors measured in quantum point contacts based on p-type heterostructures strongly depend on the orientation of the magnetic field with respect to the electric current. This effect, ...first reported a decade ago and confirmed in a number of publications, has remained an open problem. In this work, we present systematic experimental studies to disentangle different mechanisms contributing to the effect and develop the theory which describes it successfully. We show that there is a new mechanism for the anisotropy related to the existence of an additional B_{+}k_{-}^{4}σ_{+} effective Zeeman interaction for holes, which is kinematically different from the standard single Zeeman term B_{-}k_{-}^{2}σ_{+} considered until now.
Current status of tokamak T-15MD Khvostenko, P.P.; Anashkin, I.O.; Bondarchuk, E.N. ...
Fusion engineering and design,
March 2021, 2021-03-00, 20210301, Letnik:
164
Journal Article
Recenzirano
•T-15MD project is aimed at obtaining a database for creating a thermonuclear neutron source for atomic energy needs.•Magnet system of T-15MD will confine the hot plasma in the divertor ...configuration.•Toroidal magnetic field at the plasma axis is 2 T, plasma current is 2 MA.•Preparation to physical start-up of tokamak T-15MD is completed.•T-15MD should begin operation in 2021.
At the present time, the preparation to physical start-up of tokamak T-15MD is completed in the National Research Center “Kurchatov Institute”. The main parameters of T-15MD are: R = 1.48 m, a = 0.67 m, B = 2.0 T, Ipl = 2.0 MA. The magnet system is capable to maintain without overheating (more 60 °C) the plasma current of 2 MA for 4 s, 1 MA for 20 s, 700 kA for 40 s, 500 kA for 80 s, 300 kA for 160 s and 250 kA for 400 s. Plasma current drive can be maintained either by injection of fast neutrals or by electron cyclotron (EC)-, ion cyclotron (IC)- and low hybrid (LH) - waves. In August 2019 the electromagnetic system, consisting of TF and PF coils, together with vacuum vessel have been assembled in experimental hall. Power supply system of Tokamak T-15MD includes: two substations 110/10 kV, two substations 10/0.83 kV, thyristor convertors and different equipment. Total power consumption during the pulse with plasma current 2 MA and additional plasma heating of 20 MW will consist of 300 MVA. Power supply system is in the commissioning. Tokamak T-15MD will be operate using the information and control system. All the information and control system equipment, required for the implementation of physical start-up of tokamak T-15MD, is available. For plasma control the 250 different electromagnetic probes are installed inside vacuum vessel. The gyrotron with frequency 82.6 GHz and power of 1 MW will be used for pre-ionization.
III–V/Ge/Si(001), III–V/Ge/SOI(001), and III–V/GaAs(001) heterostructures are fabricated and investigated. The Ge buffer layer for the III–V/Ge/Si structure is grown by vapor deposition onto a ...Si(001) substrate via the decomposition of monogermane on a “hot wire”. In the case of III–V/Ge/SOI, the Ge buffer layer is obtained on a SOI(001) substrate by molecular-beam epitaxy via two-stage growth. The III–V layers are grown by metalorganic chemical-vapor deposition. It is shown that Ge/SOI formed by molecular-beam epitaxy using two-stage growth allows the fabrication of III–V layers that are highly competitive with those formed on Ge/Si in terms of crystalline and optical quality.
The results of model numerical calculations are presented, showing the effect of the TRT vacuum vessel on the amplitudes and phases of the magnetic sensors signals, which are located on the inner and ...outer vacuum vessel surfaces. It is shown that the characteristic times of loop voltage sensors considerably depend on their position on the TRT vacuum vessel. Therefore, their accurate mutual matching is required, especially in the dynamic stage of the discharge, when high eddy currents are induced in the vacuum vessel. The results of numerical calculations for the case of periodic disturbances in the plasma column are presented. They showed that the vacuum vessel almost completely shields the signals of the magnetic sensors located on the outer surface of the vacuum vessel. Moreover, it affects not only the amplitudes of magnetic sensors signals, but also their phases. Numerical studies brought us to conclusion that it is of priority to install the magnetic sensors just on the inner surface of the TRT vacuum vessel.
•Detail description of magnetic diagnostics of the new tokamak T-15MD.•Design and location in vacuum vessel of the inductive sensors.•Architecture of the data acquisition and plasma control system.
...Magnetic diagnostics plays an important role in tokamak operation. Magnetic data are used for the real-time control of plasma current, shape and position and for post-discharge analysis of magnetohydrodynamic (MHD) plasma instabilities and equilibrium reconstruction. The magnetic diagnostic of the T-15MD will consist of more than 350 inductive sensors of various types. Location and number of sensors is determined by the measured physical value.
The data acquisition system must simultaneously provide both the real-time data transfer of some sensors to the control loop and all sensors data storage for subsequent analysis. The requirements for the data acquisition depend on the data destination. For the data transferred to the control loop is sufficient to have a sampling rate up to 10 kHz, but this data must be transferred and processed in real-time mode. At the same time, for the study of fast processes (disruptions, tearing modes, Alfvén eigenmodes), sensor signals should be acquired with a sampling rate from 100 kHz to 2 MHz and transferred to the database in about 3 min after discharge.
The article describes the construction and location of inductive sensors, as well as the peculiarity of the magnetic diagnostics data acquisition system.
Impurity transport in the T-10 tokamak plasma with ohmic heating is studied in this paper. The values of various impurities densities, measured with the use of passive spectral diagnostics in the ...visible (Zeff), active charge exchange measurements (He, C, O), and integral bolometric measurements with absolute extreme ultraviolet detectors (Fe, W) are shown. The experimental data show that accumulation level is growing with impurity nuclear charge and determined by the parameter γ = n ¯ e Z eff I pl 1.5 , which is common for all sorts of impurities. Accumulation process is determined by neoclassical processes and begins with the increase of impurity content in the plasma and ends with the formation of density profiles more peaked than the ne(r). In discharges with low γ anomalous transport completely dominates. So it prevents the impurity accumulation and flattens their density profiles down to the ne(r). These observations correlates with measured negative (positive) plasma potential in discharges with high γ (low γ). 1D modelling using ASTRA and STRAHL transport codes is performed to describe the behaviour of impurities in a wide range of T-10 ohmic regimes. It is shown that the coefficients of anomalous transport Dan and Van established in Krupin et al (1983 Sov. J. Plasma Phys. 9 529-36) and Krupin et al (1985 12th EPS Conf. on Plasma Physics) by describing the density dynamics of injected argon and potassium ions are applicable for the modelling of the He, C, O, W impurity density profiles and their sources. The analysis of the obtained results allows us to state the existence of a common dependence of the anomalous transport for all ions (impurities and deuterons) on the discharge parameters in the T-10 ohmic regimes.
High-temperature annealing of hydrated forms of calcium silicate produced in the multicomponent system CaCl2Na2SiO3H2O yields the formation of a heterophase structure containing high-temperature ...phases of pseudo-wollastonite and silica. Under these conditions, it is observed that there is an increase in the calcium silicate crystal lattice energy, particle size, reflection coefficient in the visible and near-IR spectral ranges, and radiation stability of the synthesized powders. The improved characters make the work useful, interesting and important.
•High temperature annealing of calcium silicates.•Synthetic wollastonite produced from multicomponent system.•High-temperature phases of pseudo-wollastonite and silica.
•T-15 upgrade – the low aspect ratio tokamak with a high magnetic field, ECRH, NBI, ICRH, LH.•Main tasks: steady-state operation, plasma turbulence and confinement with an emphasis of the role of ...electric field.•Main diagnostics: CXRS/MSE, SXR, reflectometry, Thomson scattering.•Unique diagnostics: heavy ion beam probe.
Kurchatov Institute is upgrading now the T-15 tokamak to the machine with D-shaped plasma and copper magnetic system, capable for realizing lower and upper single-null and double-null magnetic configurations. The heating and current drive (CD) system consisting of the neutral beam injection (NBI), electron cyclotron resonance heating (ECRH/CD), electron Bernstein waves (EBW) heating and CD, ion cyclotron resonance heating (ICRH/CD), helicon and Lower Hybrid (LH) waves heating and CD is aiming to provide an effective heating of both electrons and ions, and on- and off-axis CD. The main research topics foreseen are the features of the confinement at high magnetic field and low aspect ratio, Advanced Tokamak regimes, steady-state operation, effects of turbulence with an emphasis on the role of the radial electric field Er, Geodesic Acoustic Modes (GAM) and Zonal Flows (ZF) in transport and confinement (including plasma self-organization, profile resiliency, influence of the q-profile), investigations of MHD effects and disruptions, Alfvén Eigenmodes (AE) and fast particles. Extended set of advanced diagnostics with identical equipment located at two toroidal positions will contribute to the 3D reconstruction of various types of the plasma structures like quasicoherent modes and long-range correlations.
Magnetotransport in mesoscopic samples with semiconductor artificial graphene has been simulated within the Landauer–Büttiker formalism. Model four-terminal systems in a high-mobility two-dimensional ...electron gas have a square shape with a side of 3–5 μm, which is filled with a short-period (120 nm) weakly disordered triangular lattice of antidots at the modulation amplitude of the electrostatic potential comparable with the Fermi energy. It has been found that the Hall resistance
in the magnetic field range of
B
= 10–50 mT has a hole plateau
, where
R
0
=
h/
2
e
2
= 12.9 kΩ, at carrier densities in the lattice below the Dirac point
n
<
n
1D
and an electron plateau
at
n
>
n
1D
. Enhanced disorder destroys the plateaus, but a carrier type (electrons or holes) holds. Long-range disorder at low magnetic fields suppresses quantized resistance plateaus much more efficiently than short-range disorder.
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