Characteristics of Magnetohydrodynamic Oscillations Observed with Michelson Doppler Imager

We report on the spatial distribution of magnetogram oscillatory power and phase angles between velocity and magnetogram signals as observed with the Michelson Doppler Imager. The dataset is 151.25 arcsec times 151.25 arcsec containing sunspot from Dec 2, 1997 with a temporal sampling interval of 60 seconds and spatial sampling of 0.605 arcsec. Simultaneously observed continuum intensity and surface velocity accompany the magnetic information. We focus on three frequency regimes: 0.5-1.0, 3.0-3.5 and 5.5-6.0 mHz corresponding roughly to timescales of magnetic evolution, p-modes and the 3 minute resonant sunspot oscillation. Significant low frequency magnetogram power is found in lower flux pixels, 100-300 Gauss, in a striking ring with filamentary structure surrounding sunspot. Five minute magnetogram power peaks in extended regions of flux 600-800 Gauss. The 3 minute oscillation is observed in sunspot umbra in pixels whose flux measures 1300-1500 Gauss. Phase angles of approximately -90 degrees between velocity and magnetic flux in the 3.0-3.5 and 5.5-6.0 mHz regimes are found in regions of significant cross amplitude.Comment: 4 Pages, 4 Figures -- For better Figure files see: http://www.astro.ucla.edu/~norton/pub_list.htm

The X-ray properties of the magnetic cataclysmic variable UUColumbae

Aims. XMM-Newton observations to determine for the first time the broad-band X-ray properties of the faint, high galactic latitude intermediate polar UUCol are presented. Methods. We performed X-ray timing analysis in different energy ranges of the EPIC cameras, which reveals the dominance of the 863 s white dwarf rotational period. The spin pulse is strongly energy dependent. Weak variabilities at the beat 935 s and at the 3.5 h orbital periods are also observed, but the orbital modulation is detected only below 0.5 keV. Simultaneous UV and optical photometry shows that the spin pulse is anti-phased with respect to the hard X-rays. Analysis of the EPIC and RGS spectra reveals the complexity of the X-ray emission, which is composed of a soft 50 eV black–body component and two optically thin emission components at 0.2 keV and 11 keV strongly absorbed by dense material with an equivalent hydrogen column density of 1023 cm−2 that partially (50%) covers the X-ray source. Results. The complex X-ray and UV/optical temporal behaviour indicates that accretion occurs predominantly (∼80%) via a disc with a partial contribution (∼20%) directly from the stream. The main accreting pole dominates at high energies whilst the secondary pole mainly contributes in the soft X-rays and at lower energies. The bolometric flux ratio of the soft-to-hard X-ray emissions is found to be consistent with the prediction of the standard accretion shock model. We find the white dwarf in UUCol accretes at a low rate and possesses a low magnetic moment. It is therefore unlikely that UUCol will evolve into a moderate field strength polar, so that the soft X-ray intermediate polars still remain an enigmatic small group of magnetic cataclysmic variables

Applications of the AVE-Sesame data sets to mesoscale studies

Data collected by the lightning data concentrator are available for research. The Mark 3 McIDAS capability provides greater flexibility for the Marshall user community and serves as a model of future UW McIDAS to remote computer links. Techniques were investigated for the display of dynamic 3-D data sets. To date the most promising display technology is a polarized two CRT perspective display which allows both dynamic 3-D images and graphics presentations with full color capability. Algorithms were for the preparation and display of conventional and satellite based weather data in 3-D. These include gridding, contouring, and streamlining processors which operate on both real time and case study data bases. An upper air trajectory model was implemented which creates a display of air parcel trajectories in perspective 3-D. A subsystem for the generation of 3-D solid surface display with shading and hidden surface display with shading and hidden surface removal was tested and its products are currently being evaluated. Motion parallax introduced by moving the point of observation during display is an important depth cue, which, when added to the perspective parallax creates a very realistic appearing display

The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: Optimization of the Spectral Line Inversion Code

The Very Fast Inversion of the Stokes Vector (VFISV) is a Milne-Eddington spectral line inversion code used to determine the magnetic and thermodynamic parameters of the solar photosphere from observations of the Stokes vector in the 6173 A Fe I line by the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO). We report on the modifications made to the original VFISV inversion code in order to optimize its operation within the HMI data pipeline and provide the smoothest solution in active regions. The changes either sped up the computation or reduced the frequency with which the algorithm failed to converge to a satisfactory solution. Additionally, coding bugs which were detected and fixed in the original VFISV release, are reported here.Comment: Accepted for publication in Solar Physic

Principles of Discrete Time Mechanics: II. Classical field Theory

We apply the principles discussed in an earlier paper to the construction of discrete time field theories. We derive the discrete time field equations of motion and Noether's theorem and apply them to the Schrodinger equation to illustrate the methodology. Stationary solutions to the discrete time Schrodinger wave equation are found to be identical to standard energy eigenvalue solutions except for a fundamental limit on the energy. Then we apply the formalism to the free neutral Klein Gordon system, deriving the equations of motion and conserved quantities such as the linear momentum and angular momentum. We show that there is an upper bound on the magnitude of linear momentum for physical particle-like solutions. We extend the formalism to the charged scalar field coupled to Maxwell's electrodynamics in a gauge invariant way. We apply the formalism to include the Maxwell and Dirac fields, setting the scene for second quantisation of discrete time mechanics and discrete time Quantum Electrodynamics.Comment: 23 pages, LateX, To be published in J.Phys.A: Math.Gen: contact email address: [email protected]

Principles of Discrete Time Mechanics: I. Particle Systems

We discuss the principles to be used in the construction of discrete time classical and quantum mechanics as applied to point particle systems. In the classical theory this includes the concept of virtual path and the construction of system functions from classical Lagrangians, Cadzow's variational principle applied to the action sum, Maeda-Noether and Logan invariants of the motion, elliptic and hyperbolic harmonic oscillator behaviour, gauge invariant electrodynamics and charge conservation, and the Grassmannian oscillator. First quantised discrete time mechanics is discussed via the concept of system amplitude, which permits the construction of all quantities of interest such as commutators and scattering amplitudes. We discuss stroboscopic quantum mechanics, or the construction of discrete time quantum theory from continuous time quantum theory and show how this works in detail for the free Newtonian particle. We conclude with an application of the Schwinger action principle to the important case of the quantised discrete time inhomogeneous oscillator.Comment: 35 pages, LateX, To be published in J.Phys.A: Math.Gen. Basic principles stated: applications to field theory in subsequent papers of series contact email address: [email protected]

Inelastic electron-nucleus scattering and scaling at high inelasticity

Highly inelastic electron scattering is analyzed within the context of the unified relativistic approach previously considered in the case of quasielastic kinematics. Inelastic relativistic Fermi gas modeling that includes the complete inelastic spectrum - resonant, non-resonant and Deep Inelastic Scattering - is elaborated and compared with experimental data. A phenomenological extension of the model based on direct fits to data is also introduced. Within both models, cross sections and response functions are evaluated and binding energy effects are analyzed. Finally, an investigation of the second-kind scaling behavior is also presented.Comment: 39 pages, 13 figures; formalism extended and slightly reorganized, conclusions extended; to appear in Phys. Rev.

Space Shuttle ice suppression system validation, volume 3

The influence of nozzle size without wind, on wind penetration, the influence of nozzle pressure on wind penetration, wind velocity effects, nozzle pressure effects, nominal velocity, wind velocity effects on wind penetration, and nozzle azimuth angle effects are plotted