Coronal temperature measurements near a helmet structure base at the 1973 solar eclipse

Observations of coronal Fe XIV emission lines from the NE quadrant during the 1973 solar eclipse are reported. Temperatures are deduced from a pure thermal broadening model, and, in the region near an observed white-light enhancement, an alternative interpretation of halfwidth as being in part due to turbulent velocities is suggested.On leave from the Los Alamos National Laboratory 1981 - present.     

Infrasonic detection of a Leonid bolide: 1998 November 17

Abstract— During the early morning hours of the night of the peak of the annual Leonid meteor shower on 1998 November 17, a bright fireball (approximately ?12 to ?14 visual magnitude at 100 km in the zenith) was observed over northern New Mexico with visual sightings as far away from Los Alamos as Albuquerque (～150 km to the south of Los Alamos), including direct persistent trail observations at the U. S. A. F. Starfire Optical Range (SOR), which is also near Albuqerque. This event did not produce any sonic boom reports, presumably because of its high altitude. It was also detected locally by an infrared radiometer at Sandia National Laboratory and by an intensified charge-coupled device (CCD) camera located in Placitas, New Mexico. Subsequent investigations of the data from the six infrasound arrays used by Los Alamos National Laboratory (LANL) and operated for the Department of Energy as a part of the Comprehensive Test Ban Treaty (CTBT) Research and Development program for the International Monitoring System (IMS) showed the presence of an infrasonic signal from the proper direction at the correct time for this bolide from two of our six arrays (both located in Los Alamos). The infrasound recordings (i.e., the wave amplitude and period data) indicated that an explosion occurred in the atmosphere at a source height of ～93.5 km (with respect to sea level) or ～90 km with respect to the altitude of Los Alamos, having its origins slightly to the north and west of Los Alamos. Purely geometric solutions from the ground observers reports combined with direct measurements from the CCD camera at Placitas produced a source height of 91 ± 7 km. The signal characteristics analyzed from 0.5 to 3.0 Hz include a total duration of about 3–4 s for a source directed from Los Alamos toward 353.6 ± 0.4° measured from true north at a maximum elevation arrival angle of ～72.7°. The latter was deduced on the basis of the observed signal trace velocities (for the part of the recording with the highest cross-correlation) and ranged from a constant value of about 920–1150 m/s (depending on the window length used in the analysis) for a ray trajectory along a direct refractive path between the source and the Los Alamos arrays. The dominant signal frequency at maximum amplitude at Los Alamos was ～0.71 Hz. These highly correlated signals had a peak to peak, maximum amplitude of ～2.1 microbars (0.21 Pa). Using several methods that incorporate various observed signal characteristics, total distance traveled, etc., our analysis indicates that the bolide probably had a source energy of ～1.14 t (TNT equivalent) or 4.77 × 10⁹ J. This is ～14.1× smaller than the source energy estimate made using the infrasonic, empirical source energy relationship for low-altitude stationary point sources developed in the 1960s by the Air Force Technical Applications Center (AFTAC), Patrick Air Force Base, Florida. This relation was originally developed, however, for much larger source energies and at much longer ranges.     

A semi-analytical approach to time-dependent coronal expansion

In this paper we point out the existence of a special class of solutions to the nonlinear hydrodynamic equations describing the time-dependent solar wind, namely that for which the velocity profile is time-invariant but the density at each point of the corona changes exponentially with time. Theoretical velocity curves are calculated for the case of isothermal expansion and compared with the Parker model for steady-state expansion. These solutions can be used to obtain quantitative estimates for the degree of departure from the latter of a real corona undergoing evolution on a finite time scale.On leave from Los Alamos Scientific Laboratory, Los Alamos, N.M., U.S.A.     

The association of coronal mass ejection transients with other forms of solar activity

Coronal mass ejection transients observed with the white light coronagraph on Skylab are found to be associated with several other forms of solar activity. There is a strong correlation between such mass ejection transients and chromospheric H activity, with three-quarters of the transients apparently originating in or near active regions. We infer that 40% of transients are associated with flares, 50% are associated with eruptive prominences solely (without flares), and more than 70% are associated with eruptive prominences or filament disappearances (with or without flares). Nine of ten flares which displayed apparent mass ejections of H-emitting material from the flare site could be associated with coronal transients. Within each class of activity, the more energetic events are more likely to be associated with an observable mass ejection.Now at Los Alamos Scientific Laboratories, Los Alamos, NM., U.S.A.The National Center for Atmospheric Research is sponsored by the National Science Foundation.     

White light and radio studies of the coronal transient of 14–15 September 1973

Observations of a coronal transient event were obtained in white light by the Skylab coronagraph and at metric wavelengths by the radioheliograph and spectrograph at Culgoora and the spectrograph-interferometer at Boulder. The continuum radio burst was found to originate above the outward-moving white light loop - a region of compressed material headed by a bow wave. The computed density in the region of radio emission, based on either gyro-synchrotron or harmonic plasma radiation mechanisms, was approximately 10 times the ambient coronal density; this is compatible with the density deduced from the white light observations. The magnetic energy density derived from the radio observations was greater than 10 times the thermal energy density, marginally larger than the kinetic energy density in the fastest moving portion of the transient, and considerably larger in most other regions. The ambient medium, the white light front, the compression region, the loop, and the slower, massive flow of material behind are each examined. It is found that the plasma was magnetically controlled throughout, and that magnetic forces provided the principal mechanism for acceleration of the transient material from the Sun.Also, High Altitude Observatory, National Center for Atmospheric Research, Boulder, Colorado.Now at Los Alamos Scientific Laboratory, Los Alamos, New Mexico.The National Center for Atmospheric Research is sponsored by the National Science Foundation.On leave from Institute of Applied Physics, University of Berne, Switzerland.Also, Division of Radiophysics, CSIRO, Sydney, Australia.     

Ring current composition and sources: An update

The composition of the Earth's ring current was reviewed at the Chapman Conference on “Magnetospheric Substorms and Related Plasma Processes,” held at Los Alamos Scientific Laboratory, Los Alamos, NM., 9–13 October 1978 (Akasofu, 1980; Williams, 1980a). It was found that the composition of the bulk of the ring current energy distribution had not been measured and several source mechanisms were possible. In this note we update that review and present recent results from Prognoz, GEOS, and ISEE instruments. Composition data and results concerning the general behavior of storm time energetic particles are shown. It is found that the ring current energy density composition still has not been observed and that the recent equatorial low energy composition results add to the particle type (charge state) and source possibilities.     

Realization of Einstein’s Machian Program: the Pioneers and fly-by anomalies Part I

In a previous paper (Berman, in Astrophys. Space Sci., 2011), we showed how to prove the two Pioneers Anomalies, and now we add the fly-bys, by means of a rotating Universe. We discuss Einstein’s Machian program, which we find as being fullfilled. Godlowski et al. (Los Alamos Archives, 2003) idea for a rotating General Relativistic Universe, led us to the adopted model. Updated evidence on rotation is cited (Godlowski, in Los Alamos Archives, 2011; Ni in Phys. Rev. Lett. 107(5):051103, 2011). We conclude that a rotating and expanding Universe may be the unique solution to the apparent divergences between Einstein and Mach. This is cosmologically important.     

Frequency of coronal transients and solar activity

The High Altitude Observatory's white light coronagraph aboard Skylab observed some 110 coronal transients - rapid changes in appearance of the corona - during its 227 days of operation. The longitudes of the origins of these transients were not distributed uniformly around the solar surface (51 of the 100 events observed in seven solar rotations arose from a single quadrant of longitude). Further, the frequency of transient production from each segment of the solar surface was well correlated with the sunspot number and Ca ii plage (area × brightness) index in the segment, rotation by rotation. This correlation implies that transients occur more often above strong photospheric and chromospheric magnetic fields, that is, in regions where the coronal magnetic field is stronger and, perhaps, more variable. This pattern of occurrence is consistent with our belief that the forces propelling transient material outward are, primarily, magnetic. A quantitative relation between transient production from an area and the Zürich sunspot number appropriate to that area is derived, and we speculate that the relation is independent of phase in the solar activity cycle. If true, the Sun may give rise to as many as 100 white light coronal transients per month at solar cycle maximum.Currently at Los Alamos Scientific Laboratory, Los Alamos, N.M., U.S.A.The National Center for Atmospheric Research is sponsored by the National Science Foundation.     

A model of protogalactic cloud collapse

The present analytical model describes the collapse of a protogalactic cloud under the influence of gravitational and viscous forces. The model provides a discriminating mechanism that dictates what type of galaxy will eventually form.Los Alamos National Laboratory is operated by the University of California for the United States Department of Energy under Contract W-7405-ENG-36.     

Comparison of a theory of sequential fragmentation with the initial mass function of stars

A one-parameter theory of sequential fragmentation is formulated, validated, and compared with the Initial Mass Function of stars. The agreement is excellent.Los Alamos National Laboratory is operated by the University of California for the U.S. Dept. of Energy under contract W-7405-ENG-36.     

Magnetic reconnection in the corona and the loop prominence phenomenon

Many classes of transient solar phenomena, such as flares, flare sprays, and eruptive prominences, cause major disruptions in the magnetic geometry of the overlying corona. Typically, the results from Skylab indicate that pre-existing closed magnetic loops in the corona are torn open by the force of the disruption. We examine here some of the theoretical consequences to be expected during the extended relaxation phase which must follow such events. This phase is characterized by a gradual reconnection of the outward-distended field lines. In particular, the enhanced coronal expansion which occurs on open field lines just before they reconnect appears adequate to supply the large downward mass fluxes observed in Ha loop prominence systems that form during the post-transient relaxation. In addition, this enhanced flow may produce nonrecurrent high speed streams in the solar wind after such events. Calculations of the relaxation phase for representative field geometries and the resulting flow configurations are described.New address: Los Alamos Scientific Laboratory, Los Alamos, N.M. 87545, U.S.A.The National Center for Atmospheric Research is sponsored by the National Science Foundation.     

Possible mass distributions in the nebulae of other solar systems

The supernova shell fragmentation model of solar system formation — previously shown to be successful in describing the mass distribution of our solar system — is used to calculate the mass distributions of other solar nebulae.Los Alamos National Laboratory is operated by the University of California for the U.S. Dept. of Energy under Contract W-7405-ENG-36.     

Metallicity,opacity coefficients and the solar standard model

We discuss the effect of the uncertainties affecting the opacities on the derived characteristics of the Sun. We consider two sources of uncertainty: the relative composition of the Sun at birth and the difference between two opacity calculations. As an illustration, we discuss the effect of the choice of photospheric or meteoritic iron abundance on the predicted chlorine neutrino capture rate and present comparisons between the Los Alamos and Limeil opacity calculations.Send offprints requests to S. Turck-Chièze.     

The supernova fragmentation model of solar system formation

We have further developed Brown's model of solar system formation. In this model, each fragment of an ejected supernova shell evolves into a separate solar system. Specifically, we have formulated the reverse-flow hypothesis that may be responsible for the inner, earthlike planets. We have written a computer program with which it is possible to calculate mass distributions within a solar nebula. We have found mass distributions similar to our solar system over a wide range of the model parameters.Los Alamos National Laboratory is operated by the University of California for the U.S. Dept. of Energy under contract W-7405-ENG-36.     

OPAL不透明度对恒星结构和演化模型的影响

本文利用国际上最新公布的OPAL不透明度表及相应的化学丰度，计算了三颗不同初始质量的星族互恒星的非守恒演化模型，并和过去长期采用的LAOL不透明度的结果进行详细比较，得出以下主要结论：（1）恒星HR图中的演化轨迹光度降低，主序位置明显向红方向移动；（2）恒星中心H，He燃烧寿命大大延长了；（3）小质量星氢燃烧核和对流核都变小，大、中质量星的中心对流核和燃烧核都有所增大；（4）恒星中心温度－密度关系基本不受影响．     

Effects of meteoroid shape on cosmogenic nuclide production processes

The shape of meteorites is one of the major factors influencing the production of cosmogenic nuclides. Numerical simulations using the Los Alamos Code System (LCS) particle production and transport codes were done to investigate particle fluxes and production rates of cosmogenic nuclides ¹⁰Be, ²⁶Al, and ⁶⁰Co in meteoroids of spherical, ellipsoidal, and cylindrical shapes. The calculations show that fluxes of nuclear active particles and also production rates of cosmogenic nuclides are sensitive to the shape of the irradiated parent body.     

Flat rotation curves according to the fragmentation/shear flow model of galaxy formation

Initial conditions are derived from the fragmentation/shear flow model of galaxy formation and are used as input to the viscous action presumed to begin as soon as a galactic disk forms. A simple differential equation is found to describe the turbulent viscous evolution of a flat disk. Solutions to this equation produce rotation curves that closely resemble those observed in spiral and elliptical galaxies. For spirals, by using the mass distributions derived from the rotation curves and from Seiden's theory of star formation, exponential luminosity profiles are produced.Los Alamos National Laboratory is operated by the University of California for the United States Department of Energy under contract W-7405-ENG-36.     

On the origin of pulsar ‘nulling’

We have discovered a correlation between the Venera spacecraft locations and the gamma-ray burst positions reported in the KONUS catalog (Mazetset al., 1981a). The reason for the correlation is not clear, but it could be due to spatial selection effects and/or large localization errors for weak of soft bursts. Whatever the cause, it seems likely that this systematic bias might significantly affect catalog results pertaining to gamma burst locations, intensity distributions, and spectra. For example, it can explain why the KONUS galactic latitude distribution is peaked significantly south of the galactic equator. Apparent discrepancies between the KONUS and Los Alamos gamma burst data bases are noted.     

Validating the Flash Code: Vortex-Dominated Flows

As a component of the Flash Center’s validation program, we compare FLASH simulation results with experimental results from Los Alamos National Laboratory. The flow of interest involves the lateral interaction between a planar M _a = 1.2 shock wave with a cylinder of gaseous sulfur hexafluoride (SF₆) in air, and in particular the development of primary and secondary instabilities after the passage of the shock. While the overall evolution of the flow is comparable in the simulations and experiments, small-scale features are difficult to match. We focus on the sensitivity of numerical results to simulation parameters.     

An indicator of galactic violence

An indicator of galactic violence is proposed, nominally equal to the total galactic mass divided by the rim radius. Four models of galaxy formation are outlined; and for each, the dependence of the rim radius on the galactic mass and the source of angular momentum is examined. If the violence indicator is small, then a normal galaxy results. If the violence indicator is large, then a galaxy with a very massive central black hole is produced (possibly a quasar). A rim radius of zero would indicate the ultimate violence and would lead directly to a non-rotating black hole of galactic mass.Los Alamos National Laboratory is operated by the University of California for the U.S. Dept. of Energy under Contract W-7405-ENG-36.