David Johnson

TL;DR: In this paper, the authors describe the requirements for high reliability in the systems (diagnostics) that provide the measurements in the ITER environment, which is similar to those made on the present-day large tokamaks while the specification of the measurements will be more stringent.

TL;DR: In this article, a multidisciplinary study was conducted in East Sound, Washington, USA between June 10 and June 25, 1998, using a nested sampling strategy utilizing four major types of platforms: (1) an array of 3 moored acoustical instrument packages and 2 moored optical instrument packages that recorded distributions and inten- sities of thin layers; (2) additional stationary instrumentation deployed outside the array comprised of meteorological stations, wave-tide gauges, and thermistor chains; (3) a research vessel anchored 150 m outside the western edge

TL;DR: The National Spherical Torus Experiment (NSTX) as discussed by the authors is one of the first ultra low a[P(input) up to 11 MW] in order to produce high-beta toroidal (25 to 40%), low collisionality, high bootstrap fraction (less than or equal to 70%) discharges.

TL;DR: In this article, the stability limits in the National Spherical Torus Experiment (NSTX) have increased significantly recently due to a combination of device and operational improvements, reaching (not simultaneously) βT = 35%, βN = 6.4, βN/li = 10, and βP = 1.4.

TL;DR: Neutral-beam-driven compressional Alfvén eigenmodes at frequencies below the ion cyclotron frequency have been observed and identified for the first time in the National Spherical Torus Experiment.