A5027387723- Magnetic confinement fusion research
- Ionosphere and magnetosphere dynamics
- Fusion materials and technologies
- Superconducting Materials and Applications
- Particle accelerators and beam dynamics
- Laser-Plasma Interactions and Diagnostics
- Plasma Diagnostics and Applications
- Solar and Space Plasma Dynamics
- Antenna Design and Analysis
- Atomic and Subatomic Physics Research
- Laser-induced spectroscopy and plasma
- Energy Harvesting in Wireless Networks
- Electromagnetic Compatibility and Measurements
- Full-Duplex Wireless Communications
- Electrohydrodynamics and Fluid Dynamics
- Nuclear Materials and Properties
- Nuclear reactor physics and engineering
- Microwave Engineering and Waveguides
- Advanced Antenna and Metasurface Technologies
- Semiconductor materials and devices
- Dust and Plasma Wave Phenomena
- Atomic and Molecular Physics
- Spectroscopy and Laser Applications
- Antenna Design and Optimization
- Plasma Applications and Diagnostics
Princeton Plasma Physics Laboratory
2016-2025
Princeton University
2014-2024
Konya Technical University
2024
Advanced Research Projects Agency - Energy
2024
General Atomics (United States)
2022-2023
Centre National de la Recherche Scientifique
2010-2023
University of Bamako
2023
Physique des interactions ioniques et moléculaires
2023
Centre Interuniversitaire de Recherche et d’Ingénierie des Matériaux
2022
Université Toulouse III - Paul Sabatier
2011-2022
Several solutions are presented to reduce the mutual coupling between two planar inverted-F antennas (PIFAs) working in close radiocommunication standards and positioned on a finite-sized ground plane modeling printed circuit board (PCB) of typical mobile phone. First, PIFAs designed separate PCBs to, respectively, operate DCS1800 UMTS bands. In second step, they associated top edge same PCB. Realistic arrangements then theoretically experimentally studied. Finally, several investigated...
Abstract The objectives of NSTX-U research are to reinforce the advantages STs while addressing challenges. To extend confinement physics low- A , high beta plasmas lower collisionality levels, understanding transport mechanisms that set performance and pedestal profiles is being advanced through gyrokinetic simulations, reduced model development, comparison NSTX experiment, as well improved simulation RF heating. develop stable non-inductive scenarios needed for steady-state operation,...
The design of several universal mobile telecommunications system multi-antenna systems with radiators having a high isolation, total efficiency and low envelope correlation is presented. First, two planar inverted-F antennas (PIFAs), closely positioned at the top edge small ground plane whose size representative printed circuit board phone, are described. A technical solution then proposed to increase isolation between enhance their when still keeping them spaced. based on an optimal...
The mechanism for blob generation in a toroidal magnetized plasma is investigated using time-resolved measurements of two-dimensional structures electron density, temperature, and potential. blobs are observed to form from radially elongated structure that sheared off by the $\mathbf{E}\ifmmode\times\else\texttimes\fi{}\mathbf{B}$ flow. generated an interchange wave increases amplitude extends response decrease radial pressure scale length. dependence upon length discussed.
The object of this review is to summarize the achievements research on Alcator C-Mod tokamak [Hutchinson et al., Phys. Plasmas 1, 1511 (1994) and Marmar, Fusion Sci. Technol. 51, 261 (2007)] place that in context quest for practical fusion energy. a compact, high-field tokamak, whose unique design operating parameters have produced wealth new important results since it began operation 1993, contributing data extends tests critical physical models into parameter ranges regimes. Using only...
Abstract WEST is an MA class superconducting, actively cooled, full tungsten (W) tokamak, designed to operate in long pulses up 1000 s. In support of ITER operation and DEMO conceptual activities, key missions are: (i) qualification high heat flux plasma-facing components integrating both technological physics aspects relevant particle exhaust conditions, particularly for the monoblocks foreseen divertor; (ii) integrated steady-state at confinement, with a focus on power issues. During phase...
Abstract A theoretical model is presented that for the first time matches experimental measurements of pedestal width-height Diallo scaling in low-aspect-ratio high- β tokamak NSTX. Combining linear gyrokinetics with self-consistent equilibrium variation, kinetic-ballooning, rather than ideal-ballooning plasma instability, shown to limit achievable confinement spherical pedestals. Simulations are used find novel Gyrokinetic Critical Pedestal constraint, which determines steepest pressure...
<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> In this letter, a novel port-to-port isolation technique suitable for two-antenna system positioned at the top corner of mobile phone is presented. The chosen planar inverted-F antennas (PIFAs) are intended to operate in UMTS band [1.922.17] GHz and more precisely Rx diversity purpose. First, distance between PIFAs severely reduced 4 mm (0.027 $\lambda_{0}$ ) order obtain very compact system....
Liquid metal plasma-facing components (PFCs) have been proposed as a means of solving several problems facing the creation economically viable fusion power reactors. To date, few demonstrations exist this approach in diverted tokamak and we here provide an overview such work on National Spherical Torus Experiment (NSTX). The Lithium Divertor (LLD) was installed operated for 2010 run campaign using evaporated coatings filling method. LLD consisted copper-backed structure with porous...
With fusion device performance hinging on the edge pedestal pressure, it is imperative to experimentally understand physical mechanism dictating characteristics and validate improve predictive models. This Letter reports direct evidence of density magnetic fluctuations showing stiff onset an instability leading saturation Alcator C-Mod tokamak. Edge stability analyses indicate that unstable both ballooning mode kinetic in agreement with observations.
Direct measurements of the pedestal recovery during an edge-localized mode cycle provide evidence that quasi-coherent fluctuations (QCFs) play a role in inter-ELM dynamics. Using fast Thomson scattering measurements, density and temperature evolutions are probed on sub-millisecond time scales to show gradient compared gradient. The appears drive for onset (as measured with magnetic probe diagnostics) localized pedestal. amplitude evolution these QCFs tracks including its saturation. Such...
We use a new gyrokinetic threshold model to predict bifurcation in tokamak pedestal width-height scalings that depends strongly on plasma shaping and aspect-ratio. The arises from the first second stability properties of kinetic-ballooning-modes yields wide narrow branches, expanding space accessible widths heights. branch offers potential for edge-localized-mode-free pedestals with high core pressure. For negative triangularity, low-aspect-ratio configurations are predicted give steeper...
Abstract A gyrokinetic threshold model for pedestal width–height scaling prediction is applied to multiple devices. shaping and aspect ratio scan performed on National Spherical Torus Experiment (NSTX) equilibria, finding <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi mathvariant="normal">Δ</mml:mi> <mml:mi>ped</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>0.92</mml:mn> <mml:msup> <mml:mi>A</mml:mi>...
A unique parabolic relation is observed to link skewness and kurtosis of around ten thousand density fluctuation signals, measured over the whole cross section a toroidal magnetized plasma for broad range experimental conditions. All probability functions including those characterized by negative skewness, are universally described special case Beta distribution. Fluctuations in drift-interchange frequency necessary sufficient assure that can be this specific
In this letter, an innovative technique is proposed to enhance the port-to-port isolation of two closely spaced dual-band radiating elements in WLAN 2.4–2.5-GHz and 5.15–5.825-GHz frequency bands. This broadband consists inserting optimized parasitic element between antennas a multiple-input–multiple-output (MIMO) set-top box. High obtained, computation diversity performance shows suitability for enhanced MIMO applications.
Experimental results from NSTX indicate that the snowflake divertor (D. Ryutov, Phys. Plasmas 14, 064502 (2007)) may be a viable solution for outstanding tokamak plasma-material interface issues. Steady-state handling of heat flux and plate erosion remains to critical issues ITER future concept devices based on conventional spherical geometry with high power density divertors. Experiments conducted in 4–6 MW NBI-heated H-mode plasmas demonstrated is compatible high-confinement core plasma...
Joint experiment/theory/modelling research has led to increased confidence in predictions of the pedestal height ITER. This work was performed as part a US Department Energy Research Target FY11 identify physics processes that control H-mode structure. The study included experiments on C-Mod, DIII-D and NSTX well interpretation experimental data with theory-based modelling codes. provides ability models for peeling–ballooning stability, bootstrap current, width scaling make correct...
Understanding the dependence of confinement on collisionality in tokamaks is important for design next-step devices, which will operate at collisionalities least one order magnitude lower than present generation. A wide range has been obtained National Spherical Torus Experiment (NSTX) by employing two different wall conditioning techniques, with boronization and between-shot helium glow discharge (HeGDC+B), using lithium evaporation (Li EVAP). Previous studies HeGDC+B plasmas indicated a...
A significant fraction of high-harmonic fast-wave (HHFW) power applied to NSTX can be lost the scrape-off layer (SOL) and deposited in bright hot spirals on divertor rather than core plasma. We show that HHFW flows these along magnetic field lines passing through SOL front antenna, implying couples across entire width mostly at antenna face. This result will help guide future efforts understand minimize edge losses order maximize heating current drive.
Research on the National Spherical Torus Experiment, NSTX, targets physics understanding needed for extrapolation to a steady-state ST Fusion Nuclear Science Facility, pilot plant, or DEMO. The unique operational space is leveraged test theories next-step tokamak operation, including ITER. Present research also examines implications coming device upgrade, NSTX-U. An energy confinement time, τE, scaling unified varied wall conditions exhibits strong improvement of BTτE with decreased electron...
The National Spherical Torus Experiment (NSTX) has undergone a major upgrade, and the NSTX Upgrade (NSTX-U) Project was completed in summer of 2015.NSTX-U first plasma subsequently achieved, diagnostic control systems have been commissioned, H-mode accessed, magnetic error fields identified mitigated, physics research campaign carried out.During ten run weeks operation, NSTX-U surpassed record pulse-durations toroidal (TF), high-performance ~1 MA plasmas comparable to best sustained near...
We report the first successful use of lithium (Li) to eliminate edge-localized modes (ELMs) with tungsten divertor plasma-facing components in EAST device. Li powder injected into scrape-off layer upper successfully eliminated ELMs for 3–5 s EAST. The ELM elimination became progressively more effective consecutive discharges at constant delivery rates, and Dα baseline emission was reduced, both signatures improved wall conditioning. A modest decrease stored energy normalized confinement also...
Abstract We report an observation of robust suppression edge-localized modes (ELMs) in the Experimental Advanced Superconducting Tokamak (EAST), enabled by continuous boron (B) powder injection. Edge harmonic oscillations appear during B injection, providing sufficient particle transport to maintain constant density and avoid impurity accumulation ELM-stable plasmas. Quasi-steady ELM discharges are demonstrated with modest energy confinement improvement over a wide range conditions: heating...
Abstract Using a recently installed impurity powder dropper (IPD), boron (<150 μ m) was injected into lower single null (LSN) L-mode discharges in WEST. IPDs possibly enable real-time wall conditioning of the plasma-facing components and may help to facilitate H-mode access full-tungsten environment The this experiment featured I p = 0.5 MA, B T 3.7 T, q 95 4.3, t pulse 12–30 s, n e,0 ∼ 4 × 10 19 m −2 , P LHCD 4.5 MW. Estimates deuterium particle fluxes, derived from combination visible...