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Research drilling in young silicic volcanoes (open access)

Research drilling in young silicic volcanoes

Magmatic activity, and particularly silicic magmatic activity, is the fundamental process by which continental crust forms and evolves. The transport of magma from deep crustal reservoirs to the surface is a neglected but important aspect of magmatic phenomena. It encompasses problems of eruptive behavior, hydrothermal circulation, and ore deposition, and must be understood in order to properly interpret deeper processes. Drilling provides a means for determining the relationship of shallow intrusive processes to eruption processes at young volcanoes where eruptions are best understood. Drilling also provides a means for directly observing the processes of heat and mass transfer by which recently emplaced intrusions approach equilibrium with their new environment. Drilling in the Inyo Chain, a 600-year-old chain of volcanic vents in California, has shown the close relationship of silicic eruption to shallow dike emplacement, the control of eruptive style by shallow porous-flow degassing, the origin of obsidian by welding, the development of igneous zonation by viscosity segregation, and the character and size of conduits in relation to well-understood magmatic and phreatic eruptions. 36 refs., 9 figs.
Date: June 30, 1989
Creator: Eichelberger, J.C.
System: The UNT Digital Library
TF-ripple loss of suprathermal alphas in ITER (open access)

TF-ripple loss of suprathermal alphas in ITER

TF-ripple loss of alphas below the critical energy is calculated for a noncircular ITER plasma. For 14 toroidal field (TF) coils, the particle loss was found to be about 6%. About 0.6% of the initial alpha energy (3.5 MeV) is lost. 26 refs., 9 figs., 3 tabs.
Date: September 30, 1989
Creator: unknown
System: The UNT Digital Library
Small scale structure on cosmic strings (open access)

Small scale structure on cosmic strings

I discuss our current understanding of cosmic string evolution, and focus on the question of small scale structure on strings, where most of the disagreements lie. I present a physical picture designed to put the role of the small scale structure into more intuitive terms. In this picture one can see how the small scale structure can feed back in a major way on the overall scaling solution. I also argue that it is easy for small scale numerical errors to feed back in just such a way. The intuitive discussion presented here may form the basis for an analytic treatment of the small structure, which I argue in any case would be extremely valuable in filling the gaps in our resent understanding of cosmic string evolution. 24 refs., 8 figs.
Date: October 30, 1989
Creator: Albrecht, Andreas
System: The UNT Digital Library
The Advanced Light Source: A new 1. 5 GeV synchrotron radiation facility at the Lawrence Berkeley Laboratory (open access)

The Advanced Light Source: A new 1. 5 GeV synchrotron radiation facility at the Lawrence Berkeley Laboratory

The Advanced Light Source (ALS), now under construction at the Lawrence Berkeley Laboratory, is being planned as a national user facility for the production of high-brightness and partially coherent x-ray and ultraviolet synchrotron radiation. The ALS is based on a low-emittance electron storage ring optimized for operation at 1.5 GeV with insertion devices in 11 long straight sections and up to 48 bend-magnet ports. High-brightness photon beams, from less than 10 eV to more than 1 keV, will be produced by undulators, thereby providing many research opportunities in materials and surface science, biology, atomic physics and chemistry. Wigglers and bend magnets will provide high-flux, broad-band radiation at energies to 10 keV. 6 refs., 10 figs., 2 tabs.
Date: June 30, 1989
Creator: Schlachter, A.S.
System: The UNT Digital Library