A test-pedestal approach, with a test grating superimposed on a masking pedestal, was used to compare sinusoidal grating vernier acuity and contrast discrimination thresholds. The goal is to develop a simple model for vernier acuity without assumptions about underlying mechanisms. In the contrast discrimination task, subjects were asked to detect contrast increments in the presence of a base pe...

Mid-latitude pedestal craters on Mars offer crucial insights into the timing and extent of widespread icerich deposits during the Amazonian period. Our previous comprehensive analysis of pedestal craters strongly supports a climate-related formation mechanism, whereby pedestals result from impacts into ice-rich material at mid latitudes during periods of higher obliquity. The ice from this targ...

Pedestal profiles that span the ELM cycle have been obtained and used to test the idea that the pedestal pressure gradient in MAST is limited by the onset of Kinetic Ballooning Modes (KBMs). During the inter-ELM period of a regularly type I ELM-ing discharge on MAST, the pressure pedestal height and width increase together while the pressure gradient increases by only 15 % during the ELM cycle....

Density pedestal formation is studied experimentally during spontaneous low-to-high confinement transitions in the H-1 heliac. Poloidally extended potential structures, or zonal flows, seem to play the major role both in the spatial structure and in the temporal evolution of the pedestal formation. Zonal flows transiently generate radially localized maxima in the radial electric-field shear in ...

during archaeological survey in 2003, a unique pedestal has been found in a farm in owjtapeh (bukān) which, upon its artistic features, seemed to belong to iron age iii and to the site of qalaychi. this pedestal has been transferred to its present place after illegal excavations. there cannot be found a similar pedestal in iran, but there are some comparable samples in assyrian sites and inscri...

The ideal magnetohydrodynamic (MHD) stability limits for the edge transport barrier (ETB) region in tokamaks are explored, concentrating in particular on the intermediate to high toroidal mode number, n, modes. These calculations take full account of the effect of the edge bootstrap current on the stability of both ballooning and peeling modes. Because the current plays an important role in MHD...

The peeling-ballooning model for edge localized modes (ELMs) and pedestal constraints, based upon ideal MHD instabilities driven by pressure gradients and current in the edge barrier region, has been broadly applied toward understanding ELM and pedestal behavior in a number of tokamak experiments. Due in part to multiple driving terms, multiple wavelengths and second stability access physics, t...

Poloidal rotation is routinely observed in present-day tokamak experiments, in particular near the plasma edge and in the high-confinement mode of operation. According to the magnetohydrodynamic (MHD) equilibrium theory [R. Betti and J. P. Freidberg, Phys. Plasmas 7, 2439 (2000)], radial discontinuities form when the poloidal velocity exceeds the poloidal sound speed (or rather, more correctly,...

A dedicated series of ELMing H-Mode discharges on Alcator C-Mod spanning a broad range of plasma parameters, including plasma current (400-1000kA), magnetic field (3.5-8T), and plasma shaping, are presented with experimental scalings of the plasma pedestal with bulk plasma and engineering parameters. The H-modes presented achieve pedestals with densities spanning 5 × 10 − 2.5 × 10 m−3 and tempe...