Recent advances in GYRO allow simulations to map out the linear stability of many eigenvalues and eigenvectors of the gyrokinetic equation (as opposed to only the most unstable) at low computational cost. In this work, GYRO’s new linear capabilities are applied to a pressure scan about the pedestal region of DIII-D shot 131997. MHD calculations in the infinite-n limit of the ideal ballooning mo...

We investigated how two co-aligned adjacent stimuli (flankers) influence threshold versus pedestal contrast (TvC) functions in binocular, monocular, and dichoptic presentations. Targets were presented to the two eyes or to only one eye. Pedestals and flankers were presented to the same eye to which the target was presented (binocular or monocular presentations) or to the other eye (dichoptic pr...

Bisection is one of several spatial localization tasks that achieve hyperacuity performance levels. We find that optimal bisection thresholds, and hyperacuity tasks in general, are no better than might be expected from simple contrast detection and discrimination performance. The three-line bisection task can be described in terms of the test-pedestal paradigm where the test pattern is a horizo...

Three experiments have provided a rough evaluation of the pointing errors of the 28-foot paraboloid and its mount. One examined the errors introduced by the pedestal, including the azimuth bearing, the second evaluated the pointing of an optical telescope attached to the backup structure, and the third showed that the departure between the telescope boresight and the millimeter-wave boresight i...

We examined achromatic contrast discrimination in asymptomatic carriers of 11778 Leber's hereditary optic neuropathy (LHON 18 controls) and 18 age-match were also tested. To evaluate magnocellular (MC) and Parvocellular (PC) contrast discrimination, we used a version of Pokorny and Smith's (1997) pulsed/steady-pedestal paradigms (PPP/SPP) thought to be detected via PC and MC pathways, respectiv...

We report on DIII–D data that reveal the underlying processes responsible for transport of energy and particles from the edge pedestal to the divertor target during Type I edge-localized modes (ELMs). The separate convective and conductive transport of energy due to an ELM is determined by Thomson scattering measurements of electron density and temperature in the pedestal. Conductive transport ...

Several problems in the physics of L→H transition and pedestal formation are examined using a simple and universal sandpile model, which incorporates key features of a confined plasma, namely, diffusion, shear induced bistability of turbulent transport, and a local magnetohydrodynamic !MHD" limit on the gradient. The main focus of this study is the effect of ambient diffusion, representative of...

Experiments were carried out to study the similarity of H-mode (High confinement mode) physics on the Alcator C-Mod [1] and DIII-D [2] tokamaks comparing plasmas with matched local edge dimensionless parameters (β, ρ∗, ν∗, q95) and shape (ε, κ, δ). It was observed that matching local values of the dimensionless parameters on top of the H-mode pedestals produces similar Te and ne profiles across...

This study addresses the development of a scaling of the H-mode pedestal in tokamak plasmas with type I ELMs. In particular, the scaling studies carried out illustrate the dependence of the pedestal properties and the resulting divertor heat load width as a function of plasma elongation and plasma current. H-mode pedestal profiles for DIII-D and Alcator C-Mod tokamaks are considered: DIII-D for...

We investigated the spatial summation effect on pedestals with difference luminance. The targets were luminance modulation defined by Gaussian functions. The size of the Gaussian spot was determined by the scale parameter (standard deviation, σ) which ranged from 0.13 to 1.04. The local luminance pedestal (2 radius) had mean luminance ranged from 2.9 to 29cd/m. The no-pedestal condition had a m...