Contribution Of Excited Hydrogen Atoms To Charge-exchange Excitation Of Impurities In Fusion Plasmas

Cross sections are calculated for charge transfer into excited states of C5+ and O7+ from collisions of C6+ and O8+ with hydrogen atoms in the n=2 and 3 levels. Effective emission cross sections that account for cascading is then derived for spectral lines emitted when the product ions decay. These are compared to the emission cross sections calculated for excitation by ground-state hydrogen. It is shown that in some circumstances the contribution from excited hydrogen atoms must be taken into account when visible lines are used to determine the oxygen or carbon density from charge-exchange spectroscopy in plasmas. Influences on Lyman-series spectra in the x-ray region are also discussed. © 1988 The American Physical Society

AVIAN SPECIATION IN THE PANTEPUI: THE CASE OF THE RORAIMAN ANTBIRD (PERCNOSTOLA [SCHISTOCICHLA] ‘‘LEUCOSTIGMA’’ SATURATA)

This is the published version. Copyright Central Ornithology Publication OfficeWe document the first records for Guyana of Roraiman Antbird (Percnostola [Schistocichla] “leucostigma” saturata), an endemic of the tepui highlands of southeastern Venezuela, northern Brazil and western Guyana. This form is well differentiated from nominate leucostigma (Spot-winged Antbird) of the Guianan lowlands in morphology, vocalizations, and genetics, and replaces it both altitudinally and ecologically. The two taxa are distributed parapatrically on the continuously forested northeastern slopes of the eastern tepuis, and they almost certainly come into contact, yet there is no evidence of intermediacy. We recommend that saturata be treated as a distinct species of Percnostola, and consider its' origin in the light of various models of speciation in the tepuis

Geometric Gravitational Forces on Particles Moving in a Line

In two-dimensional space-time, point particles can experience a geometric, dimension-specific gravity force, which modifies the usual geodesic equation of motion and provides a link between the cosmological constant and the vacuum $\theta$-angle. The description of such forces fits naturally into a gauge theory of gravity based on the extended Poincar\'e group, {\it i.e.\/} ``string-inspired'' dilaton gravity.Comment: 10 pages, CTP#214

Epinecrophylla, a new genus of antwrens (Aves: Passeriformes: Thamnophilidae)

We offer a new generic name for the stipple-throated assemblage of antwrens (Thamnophilidae) currently placed in the genus Myrmotherula. Molecular studies demonstrated that Myrmotherula is polyphyletic, with the stippled-throated group forming a clade that is not sister to any other currently recognized Myrmotherula species. The stipple-throated assemblage is distinguished morphologically by at least one sex having a black throat stippled white or buffy white combined with a comparatively long, unmarked tail, although three populations considered subspecies have lost one of these characters. The distinct evolution of this assemblage is supported by diagnostic behavioral characters derived from foraging behaviors, vocal repertoires, and nest architecture

Determination of Horizontal and Vertical Structure of a Novel Pattern of Short Period Gravity Waves Imaged During ALOHA-93

An all‐sky CCD imager has been used to measure the properties of short period gravity waves present over the Hawaiian Islands during the ALOHA‐93 campaign. Observations of emissions from four different altitudes provided a capability to describe the vertical as well as the horizontal structure of the wave field. On several occasions during this campaign an unusual morphology wave pattern was detected that consisted of a group of small‐scale waves oriented in the same direction. These were most noticeable in the OI (557.7 nm) emission, altitude ∼96 km, and were usually observed in association with a larger scale gravity wave. This paper presents a preliminary analysis of data recorded on the night of 22 October during which both types of waves were prominent. The small‐scale waves exhibited highly coherent phase structures at each emission altitude, consistent with a ducted wave motion. The spatial intensity and phase modulation of this display is indicative of interference between two waves with similar characteristics and slightly different propagation directions. The larger scale wave motion was observed to propagate perpendicular to the small‐scale waves, and showed evidence of phase progression with altitude, implying upward energy propagation. These data have been interpreted in the context of simultaneous wind measurements from an MF radar

Spectroscopy of divertor plasmas

The requirements for divertor spectroscopy are treated with respect to instrumentation and observations on present machines. Emphasis is placed on quantitative measurements.of impurity concentrations from the interpretation of spectral line intensities. The possible influence of non-Maxwellian electron distributions on spectral line excitation in the divertor is discussed. Finally the use of spectroscopy for determining plasma temperature, density, and flows is examined

Gauge Invariant Formulations of Lineal Gravity

It is shown that the currently studied ``string-inspired'' model for gravity on a line can be formulated as a gauge invariant theory based on the Poincar\'e group with central extension -- a formulation that complements and simplifies H.~Verlinde's construction based on the unextended Poincar\'e group.Comment: 11 p

Separation axioms in topological preordered spaces and the existence of continuous order-preserving functions

[EN] We characterize the existence of a real continuous order-preserving function on a topological preordered space, under the hypotheses that the topological space is normal and the preorder satisfies a strong continuity assumption, called IC-continuity. Under the same continuity assumption concerning the preorder, we present a sufficient condition for the existence of a continuous order-preserving function in case that the topological space is completely regular.Bosi, G.; Isler, R. (2000). Separation axioms in topological preordered spaces and the existence of continuous order-preserving functions. Applied General Topology. 1(1):93-98. doi:10.4995/agt.2000.3026.SWORD93981

Charge Exchange Processes between Excited Helium and Fully Stripped Ions

We made a classical trajectory Monte Carlo (CTMC) calculation of state selective cross sections for processes between some light ions and excited helium. The results, useful for analysis of spectroscopic data of fusion devices, are in good agreement with theoretical predictions of scaling laws.Comment: LaTex, 8 pages, 4 figures (available on request to the authors), DFPD/94/TH/57, to be published in Phys. Rev.