A5050251419- Magnetic confinement fusion research
- Plasma Diagnostics and Applications
- Ionosphere and magnetosphere dynamics
- Particle accelerators and beam dynamics
- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Electron and X-Ray Spectroscopy Techniques
- Geological Studies and Exploration
- Laser Design and Applications
- Fusion materials and technologies
- Methane Hydrates and Related Phenomena
- Underwater Acoustics Research
- Superconducting Materials and Applications
- Atomic and Molecular Physics
- Marine and environmental studies
- Geological and Geophysical Studies
- Gyrotron and Vacuum Electronics Research
- Material Properties and Failure Mechanisms
- Solar and Space Plasma Dynamics
- Optical Systems and Laser Technology
- Pulsed Power Technology Applications
- Ultrasonics and Acoustic Wave Propagation
- Atomic and Subatomic Physics Research
- Neutrino Physics Research
- Dust and Plasma Wave Phenomena
Kurchatov Institute
1999-2024
Golder Associates (Canada)
2020
Baikov Institute of Metallurgy and Materials Science
2020
United States Geological Survey
2009
Udmurt State University
1995-2008
Ministry of Natural Resources and Environment
2008
Acoustic Institute named after NN Andreev
2006
Russian Academy of Sciences
2004
N. I. Lobachevsky State University of Nizhny Novgorod
1972
An amplitude modulation reflectometry system is in operation at the stellarator TJ-II. Recently, first electron density profiles were obtained, showing good agreement with measured by Thomson scattering and lithium beam diagnostics. In order to measure from plasma edge, extraordinary mode of polarization used. A hyper-abrupt varactor-tuned oscillator used combination active multipliers generate two frequency segments: 25-36 36-50 etc GHz sharing a unique common wave-guide (Ka band). The...
One of the main problems which arises in density profile measurements by reflectometry is need for continuous tracking phase delay; fast fluctuations and strong modulation on amplitude reflected signal can cause ‘‘fringe jumps’’ signal. Amplitude performs a time delay measurement determination modulating envelope millimeter wave plasma. The delays involved are small, not affected be directly performed without complicated fringe counters; method provides promising possibility real plasma...
High density experiments were carried out in T-10 with gas puffing and electron cyclotron resonance heating (with absorbed power value up to 1.4 MW) oblique perpendicular launch. Densities exceeding the Greenwald limit (nGw) by a factor of 1.8 achieved regime high edge safety at current flat-top, q(a)≅8.2. The decrease q(a) 3 led reduction ratio (e) lim /nGw 1. Confinement degradation increase was not significant limit. However, typical linear energy confinement time saturates e⩾0.6nGw. This...
Tokamak plasmas have a tendency to self-organization: the plasma pressure profiles obtained in different operational regimes and even various tokamaks may be represented by single typical curve, called self-consistent profile. About decade ago local zones with enhanced confinement were discovered tokamak plasmas. These are referred as internal transport barriers (ITBs) they can act on electron and/or ion fluid. Here gradients largely exceed dictated profile consistency. So existence of ITBs...
The self-organization of a tokamak plasma is fundamental turbulent phenomenon, which leads to the formation self-consistent pressure profile. This phenomenon has been investigated in T-10 different experiments, excluding profiles with pronounced transport barriers. It will be shown that normalized profile can expressed by equation pN(r) = p(r, t)/p(0, t), over wide range densities. also independent heating power and deposition electron cyclotron resonance heating. Experiments show depends...
A modulated microwave reflectometry has been successfully developed on HL-2A, which can be used to measure the plasma density profile with time-delay method. This two frequency ranges (26.5 40 GHz and 60 GHz) it is suitable for measuring ranging from 0.8 × 1013 cm−3 4.5 cm−3. The temporal resolution 1 ms spatial about cm. paper will present basic principle of reflectometry, parameters calibration equipment experimental results HL-2A tokamak.
The study of the White Sea region and adjacent area aimed to model structure crystalline portion crust at contact northeastern slope Fennoscandian Shield Russian Plate. Modeling was based on geological, geophysical DSS profile data, State Geological Map Federation (scale 1:1 000 000), Explanatory Notes Sheets Q-35, 36, 37, 38 (third generation, 2009), Tectonic Adjacent Areas (2012). A constructed using GIS INTEGRO software (VNIIgeosystems), specifically its procedures for calculation...
A code, based on the WKB two-dimensional approximation, is used to simulate reflectometry measurements in a turbulent plasma. Fixed frequency simulations both for W7-AS and ITER parameters show an increase perturbations due turbulence as dominant wavelength becomes shorter. In larger devices perturbation stronger given level size. Density profile are simulated using pulse radar amplitude modulation (AM) (FM) reflectometers. Using some of averaging (which includes signal average time delay)...
The effect of the q(r) profile on transport barrier formation has been investigated in T-10 tokamak using rapid current ramp-up with electron cyclotron resonance heating (ECRH). enhanced core confinement (formation internal (ITB)) arises earlier than additional penetrates region. It is suggested that this process takes place due to decrease magnetic surface density region rational q = 2 βp decrease, which equivalent dq/dr near surface. At various q-profiles, and external barriers were...
In this article we present experimental results obtained with a heterodyne/amplitude modulated (AM) reflectometer at W7-AS and simulations [two-dimensional (2D) (WKB)] of reflection on rotating cutoff layer corrugated by turbulence for the conditions. When has large amplitude small size relative to illuminated spot, calculations show existence phase runaway reproduce typical behavior measured signals. It is not possible deduce plasma rotation from value “close normal” incidence, as depends...
The line-averaged electron density has been measured over a wide range of discharge conditions in low-aspect-ratio reversed field pinch (RFP) machine RELAX. A 104 GHz heterodyne interferometer was mainly used throughout the experiments. ne varied from ∼0.3 × 1019 m−3 to ∼3 m−3, depending upon conditions. new 60 homodyne interferometer, characterized by simplicity and low cost, developed for measurement particularly regime. results have shown good agreement with those system low-density...
A two-dimensional code based on the WKB (Wenzel–Kramers–Brillouin) approximation is used to simulate reflectometry measurements in plasmas with turbulence. In this work we aim understand, first role of turbulence determination density profiles and, second, ability techniques give reliable information characteristics itself. The effects profile a rotating structure nonperpendicular reflection are analyzed. influence level, fluctuation wavelengths and antenna beam size has been studied static...
Electron density profile measurements have been obtained on PBX-M by amplitude modulation reflectometry. With this technique, the measurement of time delay is from phase modulating envelope (200 MHz in PBX-M). The system operates with extraordinary mode, range 32–50 GHz. Under these conditions can be probed scrape-off layer up to typically r/a=0.7. a final bandwidth 40 kHz, reflectometer able obtain edge 1 ms. profiles are relatively noise free and good agreement Thomson scattering...
The electron density profile was measured using a microwave amplitude modulation (AM) reflectometer in Heliotron J plasmas, where plasma performance improved supersonic molecular beam injection (SMBI) as fueling method. Immediately after the SMBI pulse, for case which penetrates deeply, rapidly peaks, and increases both core edge regions. Afterward, while line-averaged is monotonically increasing, becomes more peaked. In this phase, by Langmuir probe decreases peaking factor of SX profiles...
A reflectometer, based on the amplitude modulation technique, has been developed and operated a PBX-M for measurement of electron density profile. The system, operating with extraordinary mode in range 32-50 GHz, is able to measure profile plasma edge from scrape-off layer up typically r/a=0.7. determination time delay each frequency achieved by measuring phase 200 MHz envelope superimposed millimetre wave probing signal. system final bandwidth 40 kHz obtain during 1 ms sweep microwave...
Abstract A microwave reflectometer is developed for electron density profile measurement in Heliotron J. An amplitude modulation (AM) type system adopted to reduce fluctuation effects. The carrier frequency ranges from 33 56 GHz, and the 200 MHz. X‐mode selected as propagation mode order measure a hollow which typically observed ECH plasmas. test‐bench examination using an aluminum reflection plate shows that measured phase shift agrees well with expected change position. initial results...