L. Delgado-Aparicio
A5002415651- Magnetic confinement fusion research
- Laser-Plasma Interactions and Diagnostics
- Fusion materials and technologies
- X-ray Spectroscopy and Fluorescence Analysis
- Ionosphere and magnetosphere dynamics
- Nuclear Physics and Applications
- Superconducting Materials and Applications
- Laser-induced spectroscopy and plasma
- Particle accelerators and beam dynamics
- Advanced X-ray Imaging Techniques
- Atomic and Molecular Physics
- Advanced X-ray and CT Imaging
- Plasma Diagnostics and Applications
- Atomic and Subatomic Physics Research
- Medical Imaging Techniques and Applications
- Physics of Superconductivity and Magnetism
- Solar and Space Plasma Dynamics
- X-ray Diffraction in Crystallography
- Particle Detector Development and Performance
- High-pressure geophysics and materials
- Radiation Detection and Scintillator Technologies
- Electron and X-Ray Spectroscopy Techniques
- Calibration and Measurement Techniques
- Particle Accelerators and Free-Electron Lasers
- Crystallography and Radiation Phenomena
Princeton Plasma Physics Laboratory
2014-2024
Princeton University
2006-2023
Mayo Clinic
2021
WinnMed
2021
University of Wisconsin–Madison
2021
University of Science and Technology of China
2021
National Synchrotron Radiation Laboratory
2021
Institute of Plasma Physics
2021
National Institutes for Quantum Science and Technology
2021
Kyushu University
2021
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 Ion temperatures of over 100 million degrees Kelvin (8.6 keV) have been produced in the ST40 compact high-field spherical tokamak (ST). excess 5 keV not previously reached any ST and only obtained much larger devices with substantially more plasma heating power. The corresponding fusion triple product is calculated to be <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>n</mml:mi> <mml:mi>i</mml:mi> <mml:mn>0</mml:mn>...
Disruption prediction and avoidance is a critical need for next-step tokamaks, such as ITER. Event Characterization Forecasting (DECAF) research fully automates analysis of tokamak data to determine chains events that lead disruptions forecast their evolution allowing sufficient time mitigation or complete the disruption. event related local rotating global magnetohydrodynamic (MHD) modes vertical instability are examined with warnings issued many off-normal physics events, including density...
The onset criterion for radiation driven islands [P. H. Rebut and M. Hugon, Plasma Physics Controlled Nuclear Fusion Research 1984: Proc. 10th Int. Conf. London, 1984, (IAEA, Vienna, 1985), Vol. 2] in combination with a simple cylindrical model of tokamak current channel behavior is consistent the empirical scaling density limit [M. Greenwald, Nucl. 28, 2199 (1988)]. Many other unexplained phenomena at are this novel physics mechanism.
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.
Abstract ST40 is a compact, high-field ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>B</mml:mi> <mml:mi mathvariant="normal">T</mml:mi> <mml:mn>0</mml:mn> </mml:mrow> </mml:msub> <mml:mtext>⩽</mml:mtext> <mml:mn>2.1</mml:mn> <mml:mstyle scriptlevel="0"/> <mml:mtext>T</mml:mtext> </mml:math> ) spherical tokamak (ST) with mission to expand the physics and technology basis for ST route commercial fusion. The research programme covers...
We report the observation of a correlation between shear Alfv\'en eigenmode activity and electron transport in plasma regimes where temperature gradient is flat, thus drive for microinstabilities absent. Plasmas having rapid central show intense, broadband global (GAE) 0.5--1.1 MHz range, while plasmas with low are essentially GAE-free. The first theoretical assessment GAE-electron connection indicates that overlapping modes can resonantly couple to bulk thermal electrons induce their...
This research describes advancements in the spectral analysis and error propagation techniques associated with x-ray imaging crystal spectroscopy (XICS) that have enabled this diagnostic to be used accurately constrain particle, momentum, heat transport studies a tokamak for first time. Doppler tomography been extended include of statistical uncertainty due photon noise, effect non-uniform instrumental broadening as well flux surface variations impurity density. These methods deployed suite...
Several seemingly unrelated effects in Alcator C-Mod ohmic L-mode plasmas are shown to be closely connected: non-local heat transport, core toroidal rotation reversals, energy confinement saturation and up/down impurity density asymmetries. These phenomena all abruptly transform at a critical value of the collisionality. At low densities linear regime, with collisionality ?*???0.35 (evaluated inside q?=?3/2 surface), transport exhibits behaviour, is directed co-current, edge profiles...
The characterization of plasma bursts produced after the pinch phase in a focus hundreds joules, using pulsed optical refractive techniques, is presented. A Nd-YAG laser at 532 nm and 8 ns FWHM pulse duration was used to obtain Schlieren images different times dynamics. energy, interaction time with target, power flux burst were assessed, providing useful information for application devices studying effects fusion-relevant pulses on material targets. In particular, it found that damage...
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...
The results from the investigation of neoclassical core transport and role radial electric field profile (Er) in first operational phase Wendelstein 7-X (W7-X) stellarator are presented. In plasmas, details Er expected to have a strong effect on both particle heat fluxes. Investigation is important understanding validation calculations. closely related perpendicular plasma flow (u⊥) through force balance equation. This allows be inferred measurements velocity, which can measured using x-ray...
Abstract A new record was set on the WEST Tokamak, designed to operate long duration plasmas in a tungsten (W) environment, with an injected energy of 1.15 GJ and plasma 364 s. Scenario development supported by integrated modeling using High Fidelity Plasma Simulator (HFPS), European IMAS-coupled version JETTO/JINTRAC, which integrates physics-driven modules into unified framework. In particular, reduced model for Lower-Hybrid heating Current-Drive (LHCD) quasi-linear turbulent transport...
Highly hydrophobic poly(tetrafluoroethylene) (PTFE) surfaces were modified with an air glow discharge plasma to improve their wettability. However, the hydrophilic character obtained diminishes time, due molecular movement in polymer. We have determined that ageing process is strongly affected by environment and temperature which are stored. A high temperatures promote faster recovery of original properties PTFE than low temperatures. Nonetheless, a environment, even at temperatures,...
Upgrade of the imaging X-ray crystal spectrometers continues in order to fulfill high-performance diagnostics requirements on EAST. For tangential spectrometer, a new large pixelated two-dimensional detector was deployed tokamaks for time-resolved imaging. This vacuum-compatible has an area 83.8 × 325.3 mm(2), framing rate over 150 Hz, and water-cooling capability long-pulse discharges. To effectively extend temperature limit, double-crystal assembly designed replace previous single crystals...
Core impurity transport has been investigated for a variety of confinement regimes in Alcator C-Mod plasmas from x-ray emission following injection medium and high Z materials. In ohmic L-mode discharges, is anomalous (Deff ≫ Dnc) changes very little across the LOC/SOC boundary. ion cyclotron range frequencies (ICRF) heated plasmas, core time decreases with increasing ICRF input power (and subsequent electron temperature) increases plasma current. Nearly identical characteristics are...
The major objective of the National Spherical Torus Experiment (NSTX) is to understand basic toroidal confinement physics at low aspect ratio and high βT in order advance spherical torus (ST) concept. In do this, NSTX utilizes up 7.5 MW neutral beam injection, 6 harmonic fast waves (HHFWs), it operates with plasma currents 1.5 MA elongations 2.6 a field 0.45 T. New facility, diagnostic modelling capabilities developed over past two years have enabled research team make significant progress...
The mission of the National Spherical Torus Experiment (NSTX) is demonstration physics basis required to extrapolate next steps for spherical torus (ST), such as a plasma facing component test facility (NHTX) or an ST based (ST-CTF), and support ITER. Key issues are transport, steady state high β operation. To better understand electron new high- k scattering diagnostic was used extensively investigate gyro-scale fluctuations with varying temperature gradient scale length. Results from n = 3...
New observations of the formation and dynamics long-lived impurity-induced helical ``snake'' modes in tokamak plasmas have recently been carried out on Alcator C-Mod. The snakes form as an asymmetry impurity ion density that undergoes a seamless transition from small helically displaced to large crescent-shaped structure inside $q<1$, with regularly sawtoothing core. show conditions for persistence snake cannot be explained by plasma pressure alone. Instead, many features arise naturally...
Performance predictions for future fusion devices rely on an accurate model of the pedestal structure. The candidate predictive structure is EPED, and it imperative to test underlying hypotheses further gain confidence ITER projections. Here, we present experimental work testing one EPED hypotheses, namely existence a soft limit set by microinstabilities such as kinetic ballooning mode. This extends recent Alactor C-Mod (Diallo et al 2014 Phys. Rev. Lett. 112 115001), include detailed...
In the National Spherical Torus Experiment (NSTX) [M. Ono et al., Nucl. Fusion 40, 557 (2000)], plasmas with strongly reversed magnetic shear, s≡(r∕q)(dq∕dr)&lt;0, in plasma core exhibit a marked improvement electron confinement compared to otherwise similar positive or only weakly shear. The q profile itself is determined by early evolution of current, cross section, and neutral-beam heating power. region shear reversal, thermal diffusivity can be significantly reduced. Detailed...
The National Spherical Torus Experiment (NSTX) has made considerable progress in advancing the scientific understanding of high performance long-pulse plasmas needed for future spherical torus (ST) devices and ITER.Plasma durations up to 1.6 s (five current redistribution times) have been achieved at plasma currents 0.7 MA with non-inductive fractions above 65% while simultaneously achieving β T N values 17% 5.7 (%m -1 ), respectively.A newly available motional Stark effect diagnostic...
First results of ion and electron temperature profile measurements from the x-ray imaging crystal spectrometer (XICS) diagnostic on Large Helical Device (LHD) are presented. This system has been operational since beginning 2011 LHD experimental campaign is first application XICS technique to helical plasma geometry. The provides profiles in with a spatial resolution 2 cm maximum time 5 ms (typically 20 ms). Ion possible under conditions where charge exchange recombination spectroscopy (CXRS)...
Application of lower hybrid (LH) current drive in tokamak plasmas can induce both co- and countercurrent directed changes toroidal rotation, depending on the core q profile. For discharges with q0<1, rotation increments direction are observed. If LH-driven is sufficient to suppress sawteeth increase q0 above unity, change cocurrent direction. This sign increment consistent a residual stress (the divergence which constitutes an intrinsic torque that drives flow) through its dependence...