The effects of compositional discontinuities of density and viscosity in the Earth's mantle on the ascent of mantle plume heads is studied using a boundary integral numerical technique. Three specific problems are considered: (1) a plume head rising away from a deformable interface, (2) a plume head passing through an.interface, and (3) a plume head approaching the surface of the Earth. For the...

We present simultaneous two-dimensional velocity and scalar concentrations measured on a central vertical plane in a turbulent plume. We use an edge-detection algorithm to determine the scalar plume edge, and compare the data obtained in both a fixed Eulerian frame and relative to local plume coordinates defined in terms of the instantaneous plume edge. We observe that the time-averaged distrib...

The intentional or unintentional release of a harmful atmospheric contaminant is a potentially devastating threat to homeland and defense security. Accurate identification of the source location and intensity is essential to predicting subsequent transport and dispersion of the contaminant. Insufficient spatial and temporal resolution of the available contaminant and wind-field observations mak...

The plume dynamics in the presence of an ambient gas is very intriguing physics. The expansion of a laser-produced plasma in the presence of an ambient gas leads to internal plume structures, plume splitting, sharpening, confinement, etc. We investigated propagation dynamics of an expanding tin plume for various spot sizes using a fast visible plume imaging and Faraday cup diagnostic tools. Our...

The hypothesis that thermal plumes contribute to the Cenozoic magmatism in East Africa is now widely accepted. The controversy lies on how many plumes exist and where they may be located. In this study we show numerical experiments of mantle convection models for a number of thermal plume models and discuss the implications for the melt generation in East Africa. We investigate how the plume(s)...