Novel internal measurements of ion cyclotron frequency range fast-ion driven modes

Novel internal measurements and analysis of ion cyclotron frequency range fast-ion driven modes in DIII-D are presented. Observations, including internal density fluctuation (˜n) measurements obtained via Doppler backscattering, are presented for modes at low harmonics of the ion cyclotron frequency localized in the edge. The measurements indicate that these waves, identified as coherent ion cyclotron emission (ICE), have high wave number, k⊥ρfast1, consistent with the cyclotron harmonic wave branch of the magnetoacoustic cyclotron instability, or electrostatic instability mechanisms. Measurements show extended spatial structure (at least ∼1/6 the minor radius). These edge ICE modes undergo amplitude modulation correlated with edge localized modes (ELM) that is qualitatively consistent with expectations for ELM-induced fast-ion transport

DIRECT WATER INJECTION COOLING FOR MILITARY ENGINES AND EFFECTS ON THE DIESEL CYCLE PRACTICAL SYSTEMS

A study was conducted on the feasibility" of totally cooling a single-cylinder diesel engine by direct injection of water into the combustion chanlber. The term "total cooling" can be taken to mean stabilized cooling at all loads and speeds so as to eliminate need for conventional cooling jackets, cooling fins, or oil spray jets. The engine used was a CLR Direct Injection Diesel with 42.5 cubic inch displacement and a compression ratio of 16:1. Most of the running was at 1800 rpm and 92 psi IMEP. Separate measurements were made of heat rejection to the cylinder tread, liner, and crankease oil to determine more accurately where the cooling effect was being applied. Water injection was by means of a Bosch pnmp and various pencil-type nozzles installed, adjacent to the fuel injector in the cylinder head. Port injection and port induction were also briefly investigated. A five-hole, 90 ~ included angle nozzle was used, as was a three-hole, 30 ~ included angle unit. For comparison, a nozzle directing one spray obliquely at the cylinder wall was also tested. Firing pressure was monitored using a piezo-eleetric transducer; both pressure-time and pressure~volume (indicator) records were obtained. In order to determine timing of both fuel and water injection, needle lift was monitored using a differential transformer pickup. The results of this study indicate: Optimum total engine cooling by direct water injection was accomplished over a wide range of water injection timings (from 450 to 720 CA degrees after TDC power stroke) at water/fuel ratios of 2.9 to 3.7 with output power and brake specific fuel consumption improved 5 to 20%, respectively, over that with the standard jacket-cooled CLR engine. Emissions are affected in an expected manner by the presence of water: NOx is decreased, sometimes substantially, while the other emissions (HC, CO) tend to increase. When cooling the exhaust, the condensate becomes an effective scrubber of sulfur oxides. NO~ was not significantly reduced by scrubbing, but if the condensate is made su~eiently alkaline (pH :>8), CO2 was unintentionally scrubbed out. The quail W of the uncondensed exhaust for turbooharglng is attractive. A thenretical gain of about 17.5% in available exhaust enerKy due to generation of steam was calculated, along with a temperature decrease of several hundred degrees Fahrenheit. Water contamination of the lubricating oil varies from negligible to extreme, depending on injection quantity, timing, and spray pattern. By not directing water at the liner wall, and by keeping the oil above 212~ one can maintain the oil in a dry condition. Based on this work, several pertinent recommendations have been made: (1) utilize water injection fl)r short-duration, very high-output operation which would otherwise be destructive due to thermal overload ; (2) use water induction cooling in event of loss of conventional liqnid coolant; (3) utilize exhaust scrnbbing in stationary applications to permit burning of high-sulfur fuels without producing sulfur oxide emissions; nitrogen oxides could likewise be reduced by the injection of small amounts of water; and (4) since 2-stroke-cycle engines are an important category of diesel engines, some work similar to this effort should be done to this engine type; prospects are good for success, but conditions are apt to be more restrictive

Genetic associations of hemoglobin in children with chronic kidney disease in the PediGFR Consortium

BACKGROUND: Genome-wide association studies (GWAS) in healthy populations have identified variants associated with erythrocyte traits, but genetic causes of hemoglobin variation in children with CKD are incompletely understood

NSTX-U theory, modeling and analysis results

The mission of the low aspect ratio spherical tokamak NSTX-U is to advance the physics basis and technical solutions required for optimizing the configuration of next-step steady-state tokamak fusion devices. NSTX-U will ultimately operate at up to 2 MA of plasma current and 1 T toroidal field on axis for 5 s, and has available up to 15 MW of neutral beam injection power at different tangency radii and 6 MW of high harmonic fast wave heating. With these capabilities NSTX-U will develop the physics understanding and control tools to ramp-up and sustain high performance fully non-inductive plasmas with large bootstrap fraction and enhanced confinement enabled via the low aspect ratio, high beta configuration. With its unique capabilities, NSTX-U research also supports ITER and other critical fusion development needs. Super-Alfvenic ions in beam-heated NSTX-U plasmas access energetic particle (EP) parameter space that is relevant for both α-heated conventional and low aspect ratio burning plasmas. NSTX-U can also generate very large target heat fluxes to test conventional and innovative plasma exhaust and plasma facing component solutions. This paper summarizes recent analysis, theory and modelling progress to advance the tokamak physics basis in the areas of macrostability and 3D fields, EP stability and fast ion transport, thermal transport and pedestal structure, boundary and plasma material interaction, RF heating, scenario optimization and real-time control

NSTX/NSTX-U theory, modeling and analysis results

The mission of the spherical tokamak NSTX-U is to explore the physics that drives core and pedestal transport and stability at high-β and low collisionality, as part of the development of the spherical tokamak (ST) concept towards a compact, low-cost ST-based pilot plant. NSTX-U will ultimately operate at up to 2 MA and 1 T with up to 12 MW of neutral beam injection power for 5 s. NSTX-U will operate in a regime where electromagnetic instabilities are expected to dominate transport, and beam-heated NSTX-U plasmas will explore a portion of energetic particle parameter space that is relevant for both _-heated conventional and low aspect ratio burning plasmas. NSTX-U will also develop the physics understanding and control tools to ramp-up and sustain high performance plasmas in a fullynoninductive fashion. NSTX-U began research operations in 2016, but a failure of a divertor magnetic field coil after ten weeks of operation resulted in the suspension of operations and initiation of recovery activities. During this period, there has been considerable work in the area of analysis, theory and modeling of data from both NSTX and NSTX-U, with a goal of understanding the underlying physics to develop predictive models that can be used for high-confidence projections for both ST and higher aspect ratio regimes. These studies have addressed issues in thermal plasma transport, macrostability, energetic particlet-driven instabilities at ion-cyclotron frequencies and below, and edge and divertor physics

DIII-D research advancing the physics basis for optimizing the tokamak approach to fusion energy

Funding Information: This material is based upon work supported by the US Department of Energy, Office of Science, Office of Fusion Energy Sciences, using the DIII-D National Fusion Facility, a DOE Office of Science user facility, under Awards DE-FC02-04ER54698 and DE-AC52-07NA27344. Publisher Copyright: © 2022 IAEA, Vienna.DIII-D physics research addresses critical challenges for the operation of ITER and the next generation of fusion energy devices. This is done through a focus on innovations to provide solutions for high performance long pulse operation, coupled with fundamental plasma physics understanding and model validation, to drive scenario development by integrating high performance core and boundary plasmas. Substantial increases in off-axis current drive efficiency from an innovative top launch system for EC power, and in pressure broadening for Alfven eigenmode control from a co-/counter-I p steerable off-axis neutral beam, all improve the prospects for optimization of future long pulse/steady state high performance tokamak operation. Fundamental studies into the modes that drive the evolution of the pedestal pressure profile and electron vs ion heat flux validate predictive models of pedestal recovery after ELMs. Understanding the physics mechanisms of ELM control and density pumpout by 3D magnetic perturbation fields leads to confident predictions for ITER and future devices. Validated modeling of high-Z shattered pellet injection for disruption mitigation, runaway electron dissipation, and techniques for disruption prediction and avoidance including machine learning, give confidence in handling disruptivity for future devices. For the non-nuclear phase of ITER, two actuators are identified to lower the L-H threshold power in hydrogen plasmas. With this physics understanding and suite of capabilities, a high poloidal beta optimized-core scenario with an internal transport barrier that projects nearly to Q = 10 in ITER at ∼8 MA was coupled to a detached divertor, and a near super H-mode optimized-pedestal scenario with co-I p beam injection was coupled to a radiative divertor. The hybrid core scenario was achieved directly, without the need for anomalous current diffusion, using off-axis current drive actuators. Also, a controller to assess proximity to stability limits and regulate β N in the ITER baseline scenario, based on plasma response to probing 3D fields, was demonstrated. Finally, innovative tokamak operation using a negative triangularity shape showed many attractive features for future pilot plant operation.Peer reviewe