R. Ochoukov
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View article: Characterization of W production during ICRF operations: experiments and modeling
Characterization of W production during ICRF operations: experiments and modeling Open
For successfully heating plasma with waves in the ion cyclotron range of frequencies (ICRFs), mitigating impurity production is just as crucial as maximizing power coupling, especially in high- Z environments (Urbanczyk et al 2021 Nucl. Ma…
View article: FUSION RESEARCH IN STELLARATOR DEPARTMENT OF IPP NSC KIPT
FUSION RESEARCH IN STELLARATOR DEPARTMENT OF IPP NSC KIPT Open
This paper briefly describes intrinsic and collaborative scientific activities of the Stellarator Department (Institute of Plasma Physics of the National Science Center “Kharkiv Institute of Physics and Technology”) within last two years. …
View article: Observation of bi-directional global Alfvén eigenmodes in the MAST-U tokamak
Observation of bi-directional global Alfvén eigenmodes in the MAST-U tokamak Open
The first observations and classification of deuterium beam-driven sub-cyclotron frequency range Alfvén eigenmodes (AEs) are presented for the MAST-Upgrade tokamak. Sets of observed eigenmodes are separated in frequency by approximately 20…
View article: Experimental investigation of the radial structure of energetic particle driven GAM in TCV
Experimental investigation of the radial structure of energetic particle driven GAM in TCV Open
High amplitude energetic particle geodesic acoustic mode (EGAM) oscillations driven by Neutral Beam (NBI) injected in the direction counter to the toroidal plasma current are observed in the TCV tokamak. The modes appear at frequencies clo…
View article: ICRF resonance cones in the low-density scrape-off-layer of ASDEX Upgrade
ICRF resonance cones in the low-density scrape-off-layer of ASDEX Upgrade Open
The ICRF slow wave is a potential carrier for parallel RF electric fields known to cause unwanted plasma-wall interactions in magnetic confinement fusion experiments. In nowadays machines the slow wave is usually confined to the far scrape…
View article: Experimental and numerical investigation of the Doppler-shifted resonance condition for high frequency Alfvén eigenmodes on ASDEX Upgrade
Experimental and numerical investigation of the Doppler-shifted resonance condition for high frequency Alfvén eigenmodes on ASDEX Upgrade Open
The Doppler-shifted resonance condition for high frequency Alfvénic eigenmodes has been extensively studied on ASDEX Upgrade in the presence of one or a combination of two neutral beam injected (NBI) fast ion populations. In general, only …
View article: Observation of high frequency Alfvén eigenmodes excited by RF-accelerated minority hydrogen ions in the EAST tokamak
Observation of high frequency Alfvén eigenmodes excited by RF-accelerated minority hydrogen ions in the EAST tokamak Open
The paper presents the original observation of high frequency Alfvén eigenmode excited by fast minority hydrogen ions accelerated by ion cyclotron range of frequency waves in EAST. The frequency of high frequency Alfvén eigenmodes is aroun…
View article: ICRF-specific W sources: Advances in minimization in ASDEX Upgrade and near-field based extrapolations to ITER with W-wall
ICRF-specific W sources: Advances in minimization in ASDEX Upgrade and near-field based extrapolations to ITER with W-wall Open
Experimental data from the 2022 ASDEX Upgrade (AUG) helium (He) campaign reveals that a lower tungsten (W) content can be achieved during operation of the 3-strap antennas with the W-coated limiters. By fine-tuning of electrical feeding of…
View article: An extensive analysis of SOL properties in high-δ plasmas in ASDEX Upgrade
An extensive analysis of SOL properties in high-δ plasmas in ASDEX Upgrade Open
A set of dedicated H-mode discharges with constant heating power combining Neutral Beam Injection and Electron Cyclotron Resonance Heating have been executed at the ASDEX Upgrade tokamak using a high triangularity magnetic geometry in orde…
View article: Influence of sawtooth oscillations on fast ions in a stellarator
Influence of sawtooth oscillations on fast ions in a stellarator Open
Sawtooth oscillations in tokamaks frequently lead to the redistribution of energetic ions, mainly on passing orbits, causing their expulsion from the core. This paper discusses the first measurements of the interaction of fast ions and saw…
View article: Predicting ion cyclotron emission from neutral beam heated plasmas in Wendelstein7-X stellarator
Predicting ion cyclotron emission from neutral beam heated plasmas in Wendelstein7-X stellarator Open
Measurements of ion cyclotron emission (ICE) are planned for magnetically confined fusion plasmas heated by neutral beam injection (NBI) in the Wendelstein 7-X stellarator (W7-X). Freshly injected NBI ions in the edge region, whose velocit…
View article: Interpretation of ion cyclotron emission from sub-Alfvénic beam-injected ions heated plasmas soon after L-H mode transition in EAST
Interpretation of ion cyclotron emission from sub-Alfvénic beam-injected ions heated plasmas soon after L-H mode transition in EAST Open
Ion cyclotron emission (ICE) at deuterium ion cyclotron harmonics, driven by sub-Alfvénic beam-injected deuterium ions, has been observed by the high-frequency B-dot probe in the EAST tokamak. The origin of ICE shifts from the plasma core …
View article: Analysis of high frequency Alfvén eigenmodes observed in ASDEX Upgrade plasmas in the presence of RF-accelerated NBI ions
Analysis of high frequency Alfvén eigenmodes observed in ASDEX Upgrade plasmas in the presence of RF-accelerated NBI ions Open
High frequency Alfvén eigenmodes in the ion cyclotron frequency range are actively researched on the ASDEX Upgrade tokamak (AUG). The general properties of this particular mode type are: ( a ) the mode is beam-driven and, if excited, can p…
View article: Impact of ICRF fast-ions on core turbulence and MHD activity in ASDEX upgrade
Impact of ICRF fast-ions on core turbulence and MHD activity in ASDEX upgrade Open
Funding Information: This work has been carried out within the framework of the EUROfusion Consortium, funded by the European Union via the Euratom Research and Training Programme (Grant Agreement No 101052200 — EUROfusion). Views and opin…
View article: Progress with applications of three-ion ICRF scenarios for fusion research: A review
Progress with applications of three-ion ICRF scenarios for fusion research: A review Open
Proceedings of the 24TH TOPICAL CONFERENCE ON RADIO-FREQUENCY POWER IN PLASMAS 26–28 September 2022 Annapolis, USA
View article: Overview of plasma emissions observed in the ion cyclotron frequency range on ASDEX upgrade
Overview of plasma emissions observed in the ion cyclotron frequency range on ASDEX upgrade Open
In this work we present an overview of ion cyclotron emission (ICE) signals observed on ASDEX Upgrade (AUG) with a B-dot probe array [1]. The array was recently augmented with an 8 channel digitizer (up to 250 MHz sampling rate) that makes…
View article: The geometry of the ICRF-induced wave–SOL interaction. A multi-machine experimental review in view of the ITER operation
The geometry of the ICRF-induced wave–SOL interaction. A multi-machine experimental review in view of the ITER operation Open
As part of ITPA-Integrated Operational Scenario activities, this contribution reviews recent experimental characterizations of radio-frequency (RF)-induced scrape-off layer (SOL) modifications of various tokamaks worldwide and of the LArge…
View article: New High-Confinement Regime with Fast Ions in the Core of Fusion Plasmas
New High-Confinement Regime with Fast Ions in the Core of Fusion Plasmas Open
The key result of the present work is the theoretical prediction and observation of the formation of a new type of transport barrier in fusion plasmas, called F-ATB (fast ion-induced anomalous transport barrier). As demonstrated through st…
View article: The geometry of ICRF - Induced wave-SOL interaction
The geometry of ICRF - Induced wave-SOL interaction Open
As part of ITPA-IOS activities, this contribution reviews recent experimental characterization of Radio-Frequency
(RF)-induced Scrape-Off Layer (SOL) modifications on various tokamaks worldwide and on the LArge Plasma Device
(LAPD) at UC…
View article: Determining 1D fast-ion velocity distribution functions from ion cyclotron emission data using deep neural networks
Determining 1D fast-ion velocity distribution functions from ion cyclotron emission data using deep neural networks Open
The relationship between simulated ion cyclotron emission (ICE) signals s and the corresponding 1D velocity distribution function fv⊥ of the fast ions triggering the ICE is modeled using a two-layer deep neural network. The network archite…
View article: Development of the ion cyclotron emission diagnostic for the W7-X stellarator
Development of the ion cyclotron emission diagnostic for the W7-X stellarator Open
An ion cyclotron emission (ICE) diagnostic is prepared for installation into the W7-X stellarator, with the aim to be operated in the 2022 experimental campaign. The design is based on the successful ICE diagnostic on the ASDEX Upgrade tok…
View article: Development of pre-conceptual ITER-type ICRF antenna design for DEMO
Development of pre-conceptual ITER-type ICRF antenna design for DEMO Open
ICRF antenna development for DEMO for the pre-conceptual phase is carried out by merging the existing knowledge about multi-strap ITER, JET and ASDEX upgrade antennas. Many aspects are taken over and adapted to DEMO, including the mechanic…
View article: Physics and applications of three-ion ICRF scenarios for fusion research
Physics and applications of three-ion ICRF scenarios for fusion research Open
This paper summarizes the physical principles behind the novel three-ion scenarios using radio frequency waves in the ion cyclotron range of frequencies (ICRF). We discuss how to transform mode conversion electron heating into a new flexib…
View article: Edge ICRF simulations in 3D geometry: From MHD equilibrium to coupling determination
Edge ICRF simulations in 3D geometry: From MHD equilibrium to coupling determination Open
We present in this work a consistent numerical scheme that allows the computation of 3D magnetic fields a nd 3D density profiles and their usage in ion cyclotron range of frequencies (ICRF) coupling simulations. We first utilize the PARVME…
View article: Validation of high-fidelity ion cyclotron range of frequencies antenna coupling simulations in full 3D geometry against experiments in the ASDEX Upgrade tokamak
Validation of high-fidelity ion cyclotron range of frequencies antenna coupling simulations in full 3D geometry against experiments in the ASDEX Upgrade tokamak Open
We address the validation of finite elements ion cyclotron range of frequencies (ICRF) antenna coupling simulation against experiments performed in the ASDEX Upgrade tokamak. Measurements of the loading resistance in ICRF-heated, magnetica…
View article: Publisher’s Note: “Ion temperature measurement techniques using fast sweeping retarding field analyzer (RFA) in strongly intermittent ASDEX Upgrade tokamak plasmas” [Rev. Sci. Instrum. 91, 063506 (2020)]
Publisher’s Note: “Ion temperature measurement techniques using fast sweeping retarding field analyzer (RFA) in strongly intermittent ASDEX Upgrade tokamak plasmas” [Rev. Sci. Instrum. 91, 063506 (2020)] Open
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View article: Ion temperature measurement techniques using fast sweeping retarding field analyzer (RFA) in strongly intermittent ASDEX Upgrade tokamak plasmas
Ion temperature measurement techniques using fast sweeping retarding field analyzer (RFA) in strongly intermittent ASDEX Upgrade tokamak plasmas Open
This manuscript presents a new method of interpreting the ion temperature (Ti) measurement with a retarding field analyzer (RFA) that accounts for the intermittent/turbulent nature of the scrape off layer (SOL) plasmas in tokamaks. Fast me…