TFTR D-T results

Temperatures, densities and confinement of deuterium plasmas confined in tokamaks have been achieved within the last decade that are approaching those required for a D-T reactor. As a result, the unique phenomena present in a D-T reactor plasma can now be studied in the laboratory. Recent experiments on the Tokamak Fusion Test Reactor (TFTR) have been the first magnetic fusion experiments to study plasmas with reactor fuel concentrations of tritium. The injection of {approximately} 20 MW of tritium and 14 MW of deuterium neutral beams into the TFTR produced a plasma with a T/D density ratio of {approximately} 1 and yielded a maximum fusion power of {approximately} 9.2 MW. The fusion power density in the core of the plasma was {approximately} 1.8 MW m{sup {minus}3} approximating that expected in a D-T fusion reactor. A TFTR plasma with T/D density ratio of {approximately} 1 was found to have {approximately} 20% higher energy confinement time than a comparable D plasma, indicating a confinement scaling with average ion mass, A, of {tau}{sub E} {approximately} A{sup 0.6}. The core ion temperature increased from 30 keV to 37 keV due to a 35% improvement of ion thermal conductivity. Using the electron thermal conductivity from a comparable deuterium plasma, about 50% of the electron temperature increase from 9 keV to 10.6 keV can be attributed to electron heating by the alpha particles. The {approx} 5% loss of alpha particles was consistent with classical first orbit loss without anomalous effects. Initial measurements have been made of the confined energetic alphas and the resultant alpha ash density

Surface energy and stability of stress-driven discommensurate surface structures

A method is presented to obtain {\it ab initio} upper and lower bounds to surface energies of stress-driven discommensurate surface structures, possibly non-periodic or exhibiting very large unit cells. The instability of the stressed, commensurate parent of the discommensurate structure sets an upper bound to its surface energy; a lower bound is defined by the surface energy of an ideally commensurate but laterally strained hypothetical surface system. The surface energies of the phases of the Si(111):Ga and Ge(111):Ga systems and the energies of the discommensurations are determined within $\pm 0.2$ eV.Comment: 4 pages RevTeX. 2 Figures not included. Ask for a hard copy (through regular mail) to [email protected]

The RMS Survey: Far-Infrared Photometry of Young Massive Stars

Context: The Red MSX Source (RMS) survey is a multi-wavelength campaign of follow-up observations of a colour-selected sample of candidate massive young stellar objects (MYSOs) in the galactic plane. This survey is returning the largest well-selected sample of MYSOs to date, while identifying other dust contaminant sources with similar mid-infrared colours including a large number of new ultra-compact (UC)HII regions. Aims:To measure the far-infrared (IR) flux, which lies near the peak of the spectral energy distribution (SED) of MYSOs and UCHII regions, so that, together with distance information, the luminosity of these sources can be obtained. Methods:Less than 50% of RMS sources are associated with IRAS point sources with detections at 60 micron and 100 micron, though the vast majority are visible in Spitzer MIPSGAL or IRAS Galaxy Atlas (IGA) images. However, standard aperture photometry is not appropriate for these data due to crowding of sources and strong spatially variable far-IR background emission in the galactic plane. A new technique using a 2-dimensional fit to the background in an annulus around each source is therefore used to obtain far-IR photometry for young RMS sources. Results:Far-IR fluxes are obtained for a total of 1113 RMS candidates identified as young sources. Of these 734 have flux measurements using IGA 60 micron and 100 micron images and 724 using MIPSGAL 70 micron images, with 345 having measurements in both data sets.Comment: 10 pages, 10 figures, 2 Tables, accepted to A&A. A full version of table 1 is available from the lead author or at the CDS upon publicatio

A review of Quantum Gravity at the Large Hadron Collider

The aim of this article is to review the recent developments in the phenomenology of quantum gravity at the Large Hadron Collider. We shall pay special attention to four-dimensional models which are able to lower the reduced Planck mass to the TeV region and compare them to models with a large extra-dimensional volume. We then turn our attention to reviewing the emission of gravitons (massless or massive) at the LHC and to the production of small quantum black holes.Comment: 32 pages, invited revie

Magma Ascent along a Major Terrane Boundary: Crustal Contamination and Magma Mixing at the Drumadoon Intrusive Complex, Isle of Arran, Scotland

The composite intrusions of Drumadoon and An Cumhann crop out on the SE coast of the Isle of Arran, Scotland and form part of the larger British and Irish Palaeogene Igneous Province, a subset of the North Atlantic Igneous Province. The intrusions (shallow-level dykes and sills) comprise a central quartz-feldspar-phyric rhyolite flanked by xenocryst-bearing basaltic andesite, with an intermediate zone of dark quartz-feldspar-phyric dacite. New geochemical data provide information on the evolution of the component magmas and their relationships with each other, as well as their interaction with the crust through which they travelled. During shallow-crustal emplacement, the end-member magmas mixed. Isotopic evidence shows that both magmas were contaminated by the crust prior to mixing; the basaltic andesite magma preserves some evidence of contamination within the lower crust, whereas the rhyolite mainly records upper-crustal contamination. The Highland Boundary Fault divides Arran into two distinct terranes, the Neoproterozoic to Early Palaeozoic Grampian Terrane to the north and the Palaeozoic Midland Valley Terrane to the south. The Drumadoon Complex lies within the Midland Valley Terrane but its isotopic signatures indicate almost exclusive involvement of Grampian Terrane crust. Therefore, although the magmas originated at depth on the northern side of the Highland Boundary Fault, they have crossed this boundary during their evolution, probably just prior to emplacemen

Affordable Near-term Burning-plasma Experiments

Fusion energy is a potential energy source for the future with plentiful fuel supplies and is expected to have benign environmental impact. The issue with fusion energy has been the scientific feasibility, and recently the cost of this approach. The key technical milestone for fusion is the achievement of a self-sustained fusion fire, ignition, in the laboratory. Despite 40 years of research and the expenditure of almost $20B worldwide, a self-sustained fusion fire has not yet been produced in the laboratory. The fusion program needs a test bed, preferably more than one, where the dynamics of a burning plasma can be studied, optimized and understood so that the engineering requirements for an engineering test reactor can be determined. Engineering and physics concepts must be developed within the next decade that will lead to an Affordable Burning Plasma Experiment if fusion is going to be perceived as making progress toward a potential long-range energy source