UAH Physics Seminars

Special Seminar: Thursday, 29 May 2008, 2:15pm, OB 234

Mon, 05 May 2008 10:08:02 -0500

Particle acceleration and transport in the inner heliosphere

Energization and transport of charged particles in the inner heliosphere has been a long standing problem in space plasma physics. At 1 AU, solar energetic particles (SEPs) with energies upto ~ 1 GeV arrive routinely. They interact with the Earth's magnetosphere, cause communication disruptions, pose radiation threats to spacecraft and astronauts, and are the main subject of NASA's space weather study. At least for one class of the solar energetic particle events, the so-called gradual SEP events, it is believed that the acceleration of particles is via shock acceleration at CME-driven shocks. As a CME-driven shock propagates out, particles are picked up at the shock front, accelerated through 1st-order Fermi-acceleration mechanism. Upstream of the shock, particles are capable of escape. When they do, they generate and amplify upstream Alfven waves, further enhance the subsequent acceleration process; leading to an integrated system with self-consistent particle acceleration and wave generation. Escaped particles propagate in the inner heliosphere following the Parker's spiral, with pitch angle scatterings. Pitch angle scattering describes the effect of turbulent magnetic field on charged particles and is a continuous stochastic process. Obviously, to decipher the observed time intensity profile and spectra at 1 AU for gradual SEP events, a detailed model treating shock propagation, particle acceleration, and particle transport is necessary. In this talk, I will discuss particle acceleration and transport in the inner heliosphere, putting into the context of the PATH (Particle Acceleration and Transport in the inner Heliosphere) model that I have been working in the past several years.

Dr. Gang Li obtained his Ph.D in nuclear astrophysics and Master in computer science from Indiana University in October 2000. His thesis work was on neutrino transport in Supernova and he won the outstanding graduate research award from Physics Department. He joined IGPP at University of California at Riverside as a post-doc late 2001 and became an professional researcher in 2004. In February 2006, he took a Assistant research physicist position in Space Science Lab at University of California, Berkeley. In his spare time, he loves hiking and playing badminton. Since February 2008, the arrival of his son, Luke, however, took all his spare time away.

Dr. Gang Li
UC Riverside

Special Seminar: Tuesday, 27 May 2008, 2:15 pm, OB 234

Mon, 05 May 2008 09:47:18 -0500

Cosmic ray interaction with plasma flows in the heliosphere

Cosmic rays comprise several ubiquitous particle populations in the solar system. Galactic cosmic rays are highly energetic particles originating from outside the solar system that serve as probes of magnetic fields and turbulence inside the heliosphere, while anomalous cosmic rays, being of heliospheric origin, offer unique insights into the physics of charged particle acceleration at highly oblique astrophysical shocks. The outstanding problem of modern cosmic-ray physics is understanding the interaction of these energetic particles with the global structure of the heliosphere. A number of heliospheric cosmic-ray transport models have been developed over the past 7 years at the UC Riverside to study in detail the interaction of cosmic rays with turbulent plasma flows in and around the solar system. Two principal applications of our models are discussed: (a) galactic cosmic-ray modulation in the heliosheath and (b) the response of anomalous cosmic rays to the variability of the termination shock induced by transient structures in the solar wind. My results suggest that the heliosheath is responsible for over half of the total modulation of cosmic rays with energies below 500 MeV, in agreement with Voyager observations. I also argue that the unexpected deficiency in the anomalous cosmic rays fluxes discovered by the Voyagers is a consequence of dynamical evolution of the termination shock.

Vladimir Florinski received his MS in Physics from the St. Petersburg State Technical University in St. Petersburg, Russia, in 1997. He did his PhD research on galactic and anomalous cosmic ray transport under the guidance of J. R. Jokipii at the University of Arizona. His PhD in Planetary Science was awarded in 2001. After graduation, Florinski worked as a postdoctoral researcher for G. P. Zank at the University of California in Riverside, where he is currently a Professional Researcher. Florinski is an author of over 50 publications and a co-organizer of several international astrophysics conferences. His principal research area is theoretical modeling of the full range of physical phenomena occurring in the outer heliosphere.

Dr. Vladimir Florinski
UC Riverside

Special Seminar: Thursday, 22 May 2008, 2:15pm, OB 234

Fri, 09 May 2008 09:20:56 -0500

MHD-neutral Model of the Outer Heliosphere

I describe the model of the solar wind (SW) interaction with the local interstellar medium (LISM) which takes into account the coupling of the interstellar and interplanetary magnetic fields (ISMF and IMF) at the heliospheric interface, charge exchange/collisions between ions and atoms, and time-dependent phenomena. The asymmetry of the heliosphere under the combined action of the interstellar magnetic field and charge exchange is analyzed. The solutions are shown for different ISMF orientations. The possibility is discussed of using the SOHO SWAN data on the deflection of neutral hydrogen flow from its original orientation in the unperturbed LISM as an ISMF compass. The effects of the solar cycle and SW transients are discussed. A newly developed package of scientific programs is described which was developed for solution of multi-scale space physics and astrophysics problems involving flows of charged and neutral particles that require gas dynamic, MHD, and kinetic treatment. The results are presented of the package application to numerical modeling of the outer heliosphere, in particular, to the problem of stability of the heliopause and heliospheric current sheet behavior.

Nikolai V Pogorelov
Institute of Geophysics and Planetary Physics
University of California, Riverside

Special Seminar: Monday, 19 May 2008, 2:15pm, OB 234

Mon, 05 May 2008 10:20:18 -0500

New Insights into Interstellar Pickup Ion Acceleration at the Heliospheric Termination Shock and in the Heliosheath

For many years prior to the discovery of the heliospheric termination shock (HTS) by the Voyager spacecraft, many anomalous cosmic-ray modulation effects observed upstream of the HTS could be explained satisfactorily by using the standard cosmic-ray transport equation to model the steady-state diffusive shock acceleration (DSA) of anomalous cosmic rays at the HTS. However, the first Voyager HTS crossings during 2004 and 2007 showed that energetic ion observations at the HTS cannot be easily explained within the confines of standard steady state DSA theory which is based on the assumption of energetic particles with nearly isotropic distributions. Observations such as upstream magnetic field-aligned energetic ion beams with large pitch-angle anisotropies that are highly volatile, an unexpected high energy peak in the upstream pitch-angle anisotropy, a large highly anisotropic intensity spike at the HTS, energetic ions with multiple power law spectral slopes, and spectral slopes that are harder than expected from steady state DSA theory, require a more sophisticated approach to DSA that is time dependent and is not restricted to small anisotropies. I will show that these observations can potentially be explained when modeling the DSA of pickup ions at the HTS with a time-dependent focused transport model. Secondly, first observations of the termination shock structure by the Voyager 2 spacecraft clearly suggest that the HTS is modified by accelerated pickup ions on macroscopic as well as microscopic spatial scales. This indicates that reflection and heating of pickup ions rather than solar wind ions by the cross-shock potential is important and that DSA at the HTS is a nonlinear process. I will discuss a promising self-consistent kinetic-three-fluid model that we developed that promises to give a good account of these observations. Thirdly, strong compressive turbulence is currently observed in the turbulent heliosheath. This begs the question whether turbulent diffusion and stochastic acceleration by compressive turbulence in the heliosheath could explain observations that suggest that HTS accelerated pickup ions are further accelerated to higher energies in the heliosheath. I will discuss this possibility based on theoretical work we did on energetic ion transport and energization in compressive wave turbulence.

Dr. Jakobus le Roux
UC Riverside

Special Seminar: Thursday, 15 May 2008, 2:15pm, OB 234

Mon, 05 May 2008 10:13:22 -0500

Turbulence in Interstellar Medium Plasma: A Coupled Plasma-neutral Fluid Model in the Heliosphere

A local turbulence model is developed to study energy cascades in the interstellar medium (ISM) based on self-consistent two-dimensional fluid simulations. The model describes a partially ionized magnetofluid interstellar medium (ISM) that couples a neutral hydrogen fluid with a plasma primarily through charge exchange interactions. Charge exchange interactions are ubiquitous in warm ISM plasma and the strength of the interaction depends largely on the relative speed between the plasma and the neutral fluid. Unlike small length-scale linear collisional dissipation in a single fluid, charge exchange processes introduce channels that can be effective on a variety of length-scales that depend on the neutral and plasma densities, temperature, relative velocities, charge exchange cross section and the characteristic length scales. We find, from scaling arguments and nonlinear coupled fluid simulations, that charge exchange interactions modify spectral transfer associated with large scale energy containing eddies. Consequently, the warm ISM turbulent cascade rate prolongs spectral transfer amongst inertial range turbulent modes. Turbulent spectra associated with the neutral and plasma ISM fluids are therefore steeper than those predicted by Kolmogorov's phenomenology. This work has important implications for the nature of the interstellar medium, especially in understanding heating characteristics, cosmic ray transport, interstellar medium processing by a partially ionized plasma, and molecular clouds and star formation processes where ion-neutral interaction influence magnetic fields.

Dr. Dastgeer Shaikh
UC Riverside

Special Seminar: Monday, 12 May 2008, 2:15pm, OB 234

Mon, 05 May 2008 09:46:03 -0500

Seeing the heliosphere through energetic neutral atoms

The interaction of the solar wind with the partially ionized plasma of the local interstellar cloud is investigated. We introduce the concept of the heliosphere as a bubble of solar wind embedded in the local interstellar medium. With the help of 2D and 3D numerical simulations, we investigate the effects of interstellar neutral hydrogen on the heliosphere, and various approaches to modeling neutral atoms will be discussed. These neutral atoms are coupled to the plasma through charge-exchange, but since the mean free path is of the order of the heliosphere itself, the coupling has a variety of non-local features. We then look at observational implications of neutral atoms in the heliosphere, in particular for the upcoming IBEX mission. We show, by using data from our simulations, how all-sky maps of energetic neutral atoms (ENA's), born through charge-exchange in the heliosheath, can yield information about the structure of the heliosphere. It is envisioned that IBEX data will help to constrain models of the heliosphere and thereby improve our understanding of the farthest reaches of the Sun's environment.

Undergrad and grad studies at the University of Waikato in New Zealand, graduated in 2001. Held a temporary position as assistant professor at the same place. Worked mainly on solutions to the MHD equations to describe magnetic reconnection. Came to Riverside in 2003 as Post-doc. Promoted to assistant professional researcher in 2004. Developed a Monte-Carlo code which kinetically models hydrogen atoms in the heliosphere and coupled this to an MHD code for the ionized plasma.
Dr. Jacob Heerikhuisen
UC Riverside

Colloquium: 22 April 2008, 2:30pm, OB 234

Wed, 23 Apr 2008 11:41:51 -0500

Ex Luna, Scientia!

The Lunar Occultation Observer (LOCO) is a new mission concept being developed to probe the nuclear astrophysics regime.By combining the development heritage of planetary orbital-geochemistry investigations with new developments in astrophysical imaging, a high-sensitivity, scaleable, and cost effective mission is feasible. LOCO will perform an all-sky survey of the Cosmos and study a wide range of astrophysical phenomena including, but not limited to, Galactic nucleosynthesis, supernovae & novae, potential dark matter annihilation processes, active galactic nuclei, and compact objects. I will describe the motivating science, the mission concept, as well as ongoing research and development.

Dr. Richard Miller
UAH

Colloquium: 15 April 2008, 2:30pm, OB 234

Mon, 07 Apr 2008 16:04:28 -0500

Nanophotonics: From Photonic Crystals to Plasmonics

In this special seminar, I’m going to play a documentary DVD, which shows a plenary presentation given by Professor Eli Yablonovitch of UC Berkeley at the Frontiers in Optics Conference last September. Dr. Yablonovitch is widely regarded as the father of photonic crystals. In this beautifully organized talk, he took the audience on a tour of structures far smaller than the wavelength of light and reviewed the latest progress in three of today’s hottest areas in optics: photonic crystals, silicon photonics and plasmonics. When the size of integrated circuits dropped below the critical dimension for a photonic crystal, which is about 100 nm, electronics and optics have become one thing. With the breakthrough of silicon lasers, a full toolkit for integrated optoeletronics is at hand. Finally, the emerging field of plasmonics will eventually make possible integrated optical circuits.

To help students with limited optics background better understand the talk, I’m going to give a brief tutorial of some of the background knowledge before the presentation. This will be a good opportunity for students to get a taste of conference and learn about the latest development in the field from a world-class expert.

Dr. Lingze Duan
UAH Physics

Colloquium: 8 April 2008

Mon, 31 Mar 2008 14:02:28 -0500

No talk today. UAH Honors Day.

Colloquium: 1 April 2008, 2:30pm, OB 234

Mon, 24 Mar 2008 08:36:06 -0500

The Polar Ultraviolet Imager (UVI): A Dozen Years of Auroral Science

The Polar satellite, originally scheduled for a two-year mission, recently celebrated its twelve-year anniversary of operations. The Ultraviolet Imager (UVI), one of three imagers on Polar, is a camera designed to view Earth’s aurora in ultraviolet wavelengths. That remarkable mission is now drawing to a close and the Polar satellite is scheduled to be shut down by the end of the month. This presentation is intended to be a celebration of the UVI investigation and, more importantly, a tribute to the UAH-MSFC collaboration that designed, built, tested and operated the instrument. UVI images allow scientists to monitor the location and behavior of the aurora, determine auroral energies and properties of Earth’s upper atmosphere. Advantages of space-based imaging of the aurora and imaging of the upper atmosphere in general will be discussed. Results will be presented from UVI and form other global imagers before and after the Polar era.

Dr. Glynn Germany, UAH/CSPAR

Colloquium: 25 March 2008, 2:30pm, OB 234

Mon, 24 Mar 2008 08:31:27 -0500

The FUSE Survey of Diffuse O VI Emission from the Interstellar Medium

Emission via the O VI doublet at 1031.93 and 1037.62 A is the primary cooling mechanism for interstellar gas at temperatures between 10^5 and 10^6 K. As such, it traces regions where hot gas cools quiescently, interface regions where hot and cool gas meet and mingle, and high-velocity shocks. Over its eight-year mission, the Far Ultraviolet Spectroscopic Explorer (FUSE) was used to observe O VI in both emission and absorption. In this talk, I will present a brief history of the hot component of the interstellar medium (ISM) and the various physical processes responsible for its creation, evolution, and morphology. I will review the results of recent O VI absorption- line studies of the Galactic disk and halo. Finally, I will present the latest results from our survey of diffuse O VI emission from the ISM.

Our observations reveal the large-scale structure of the O VI-emitting gas in the quadrant of the sky centered on the Magellanic Clouds. Its most prominent feature is a layer of low-velocity emission that extends more than 70 degrees from the Galactic plane. By combining absorption and emission measurements along the same lines of sight, we can estimate the emission measure and therefore the density of the emitting gas. We identify two distinct populations of emitting clouds: At low latitudes (|b| <30 deg), we probe narrow, high-
density conductive interfaces in the local ISM. At high latitudes, the low densities and long path lengths are consistent with a location in the Galactic thick disk/halo. Three of our sight lines exhibit O VI emission at velocities consistent with Magellanic H I, suggesting that hot and cool gas is mixing in the interface region of the Magellanic System.

Dr. Van Dixon
Johns Hopkins University Dr. Van Dixon
Johns Hopkins University

Colloquium: 18 March 2008

Thu, 13 Mar 2008 08:17:37 -0500

None. Spring Break.

Colloquium: 11 March 2008, 2:30pm, OB 234

Thu, 13 Mar 2008 08:14:55 -0500

Understanding Cometary Atmospheres

Understanding the chemical and physical properties of cometary atmospheres is crucial to understanding comets as a whole. However, many properties of cometary atmospheres are still not understood. This is further compounded by the lack of models incorporating information gathered from comet flyby missions. I will discuss my recent and ongoing work to examine the potential impact of gas dynamics, photochemistry, and chemical reactions on the chemical profiles of cometary atmospheres, including an attempt to model chemical profiles in the atmosphere surrounding a non-spherical nucleus. The results have implications for measuring chemical abundances in comets, and in turn, measuring chemical abundances in the outer Solar System and placing constraints on scenarios of Solar System formation.

Dr. Donna Pierce
Mississippi State University

Colloquium: 4 March 2008, 2:30pm, OB 234

Mon, 25 Feb 2008 15:49:03 -0600

Measuring the Magnetic Field in the Solar Corona

The corona is the outermost layer of the Sun's atmosphere. Remarkably, it has a temperature of 1-2 million degrees Kelvin, while the layers of gases in the photosphere only a few thousand kilometers below (which we see as the disk of the Sun) have a temperature of about 6000 K. The structure of the corona is partly determined by a magnetic field, as may be seen in pictures of solar eclipses. This magnetic field is widely believed to play a role in the heating of the corona, either directly via Joule heating or indirectly via the damping of waves and turbulence which involve the magnetic field. Assessing this role requires measurements of the strength and structure of the coronal magnetic field. I will describe ways in which such information can be obtained by radioastronomical measurements. The physical effect at the basis of these measurements is Faraday Rotation, consisting of a rotation of the plane of polarization of a radio wave when it propagates through an ionized gas with a magnetic field.

Dr. Steve Spangler
University of Iowa

Colloquium: 26 Feb 2008, 2:30pm, OB 234

Wed, 20 Feb 2008 14:06:20 -0600

Electric Redshift and Quasars

Recently, a new redshift mechanism called electric redshift is developed by Zhang (ApJL 636, 61, 2006), in accord with the five-dimensional fully covariant Kaluza-Klein (K-K) theory with a scalar field, which unifies the four-dimensional Einsteinian general theory of relativity and the Maxwellian electromagnetic theory. The result indicated that a dense, massive, and charged object can significantly shift the light that is emitted from the object toward the red as compared with the Einsteinian gravitational redshift. A compact, electrically charged object with density and mass comparable to those of a neutron star can impart a redshift as great as quasars have. This seminar introduces this new redshift mechanism and discusses the detectability of the electric redshift and the scalar field interaction with possible experiments.

Dr. T. X. Zhang
Alabama A&M University

Colloquium: 19 Feb 2008, 2:30pm, OB 234

Thu, 14 Feb 2008 13:47:35 -0600

Relativistic MHD Simulations of Relativistic Jets

Relativistic jets have been observed or postulated in various astrophysical sources, including active galactic nuclei (AGNs), microquasars in the galaxy and gamma-ray bursts (GRBs). There are four major problems related to the relativistic jets: 1. formation mechanism, 2. acceleration mechanism, 3. collimation mechanism, and 4. long-term stability. The most promising mechanisms for producing and accelerating relativistic jets, and maintaining collimated structure of relativistic jets involve magnetohydrodynamical processes.

We perform 2D general relativistic MHD simulations involving a geometrically thin accretion disk near both non-rotating and rotating black holes by using newly-developed 3D GRMHD code ``RAISHIN''. In the rotating black hole case an inner jet forms near the black hole region in the magnetic field strongly twisted by frame-dragging. This inner jet/spine lies within an outer jet/sheath produced by the magnetic fields anchored accretion disk. When the jet propagates, such a jet/spine and sheath/wind configuration considerably modifies the stability properties and potential structure of the jet resulting from spine-sheath interaction. We have performed 3D relativistic MHD simulations to study the Kelvin-Helmholtz (KH) instability of magnetized spine-sheath relativistic jets. We found that the growth of the KH instability is reduced significantly by a mildly relativistic sheath flow and can be stabilized by a magnetized sheath flow.

Dr. Y. Mizuno
MSFC/NSSTC

PhD Dissertation Talk: 20 Feb 2008, 2:30pm, OB 234

Mon, 11 Feb 2008 11:36:10 -0600

Vaporization and Shock Wave Dynamics for Impulse Generation in Laser Propulsion

A high-power carbon dioxide laser was used to ablate bulk liquid, polymer, and thin film targets. Time-resolved force sensing measurements, ballistic pendulum impulse measurements, and quantitative shadowgraph and Schlieren imaging techniques were used to study ablation. Propulsion parameters (including imparted impulse, momentum coupling coefficient, ablated mass, specific impulse, and internal efficiency) were measured for the materials when possible. In addition, a detailed examination was conducted as to the dependence of these parameters on the absorption depth of the materials, and on the fluence at the target. An initial study was made on the scaling of the propulsion parameters with the ablated spot area. The effects of varying the thin film thickness on the impulse were also noted. A calibration technique for piezoelectric force sensors was developed using impacts of spheres on the sensors. Finally, a basic physical analysis of the propulsive quantities was made that raises questions about the standard interpretation of the dependence of the coupling coefficient on the fluence.

Mr. John Sinko
UAH Physics

Colloquium: 12 Feb 2008, 2:30pm, OB 234

Fri, 08 Feb 2008 20:55:59 -0600

Quantitative Detection of Proteins Using an Evanescent Based Fiber-Optic Biosensor

In recent years, there is a considerable increase in the research efforts in the field of fiber-optic biosensors. Because of their potential sensitivity, detection speed and adaptability to a wide variety of assay conditions, their use as a probe or as a sensing element is increasing in clinical, pharmaceutical, industrial and military applications. I will talk about design aspects of a fiber-optic probe and converting it into a highly sensitive and specific tool for rapid and cost-effective detection and quantification of proteins in serum/plasma samples.

Dr. R. Kapoor
UAB

Colloquium: 5 Feb 2008, 2:30pm, OB 234

Mon, 04 Feb 2008 09:47:33 -0600

Experimental Studies of Charging of Lunar Dust: Levitation, Adhesion, & Transportation

It is well known since the Apollo missions that the lunar surface is covered with a thick layer of micron size dust grains with unusually high adhesive characteristics. The dust grains levitated and transported on the lunar surface are believed to have a hazardous impact on the robotic and human missions to the Moon. A horizon glow and transient dust clouds over the lunar horizon were observed by during the Apollo 17 mission. The observed dust phenomena are attributed to the lunar dust being charged positively during the day by UV photoelectric emissions, and negatively during the night by the solar wind electrons. The dust grains are believed to be levitated by the induced electric fields and transported in the near vacuum environment. The current dust charging and the levitation models, however, do not fully explain the observed phenomena, with the uncertainty of dust charging processes and the equilibrium potentials of the individual dust grains. Since the abundance of dust on the Moon's surface with its observed adhesive characteristics has the potential of severe impact on human habitat and operations and lifetime of a variety of equipment, it is necessary to investigate the charging properties and the lunar dust phenomena in order to develop appropriate mitigating strategies.

It is well recognized that the charging properties of individual dust grains are substantially different from those determined from measurements made on bulk materials that are currently available. An experimental facility has been developed in the Dusty Plasma Laboratory at NASA Marshall Space Flight Center for investigating the charging and optical properties of individual micron/sub-micron size dust grains by levitating them in an electrodynamic balance in simulated space environments. I will discuss our recent results on laboratory measurements on charging of Apollo 11 and 17 individual lunar dust grains by low energy electron beams and by photoelectric emissions. The measurements are made by levitating dust grains of 0.2 to 10 mm diameters, in an electrodynamic balance and exposing them to mono-energetic electron beams and UV radiation. The charging rates and the equilibrium potentials produced by UV radiation and by electron impact are discussed. Photoelectric emission induced by the solar UV radiation is recognized to be the dominant process for charging of the lunar dust. In a unique laboratory facility at MSFC/NSSTC, the optical and physical properties of individual lunar dust grains are being investigated with the objective to better understand the complex lunar dust phenomena in order to develop and evaluate various mitigating strategies. We will discuss the first laboratory measurements of the photoelectric yields of individual sub-micron/micron size dust grains selected from sample returns of Apollo 17, and Luna 24 missions, as well as similar size dust grains from the JSC-1 simulants. The measured yields of micron-size individual dust grains are determined to be more than an order of magnitude larger than the bulk values reported in the literature, with a size dependence that indicates higher values for larger grains. The current and future experimental and analytical programs for investigations of the lunar dust phenomena will be discussed.

Dr. Mian Abbas
NASA MSFC

Special Seminar: 31 Jan 2008, 2:30pm, OB 234

Mon, 28 Jan 2008 08:32:34 -0600

Ultra-High-Energy Cosmic Rays: New Results from the Auger Array

The highest energy cosmic ray particles are the most energetic particles known to us in the universe, and their observations have led us to build one of the largest detector system in the world, the Auger air-shower array. We have detected particles of an energy up to 3x10^20 eV, which is a macroscopic energy. There have been two predictions: one that due to interaction with the microwave background the spectrum should show a turnoff near 5x10^19 eV; this has been confirmed by two experiments, HiRes and Auger. Second, that radio galaxies should be the accelerators, based on the non-thermal optical spectra of knots and hot spots in radio galaxies; this is now tentatively confirmed by Auger. Apart from differentiating various remaining options how to generate these particles, there is one major difficulty: the lack of understanding of the cosmological web of magnetic fields, which may influence the propagation of high energy particles; here it is especially important to understand the role of a galactic wind and its magnetic structure. In analogy to the scattering of particles in the Solar wind I propose, that this scattering leads to a steep distribution function of scattering angles of the deviation from a straight line path for the arriving particles. I will discuss the observational and theoretical limits for an exemplary set of models, the predictions, that result from these models, and how present and future observations will test our conclusions, especially with the Telecope Array (TA), the Auger Array, the neutrino observatory IceCube, and the future space observatory EUSO. There are a number of exciting consequences for high energy physics.

Dr. Peter Biermann
Max Planck Institute (Bonn)

Colloquium: 29 Jan 2008, 2:30pm, OB 234

Wed, 23 Jan 2008 08:37:13 -0600

Heliophysics Science and the Moon

The Moon is immersed in a plasma environment - the local cosmos - that is "magnetized." It is threaded with magnetic fields that are often "frozen" into the plasma, a state of high electrical conductivity that effectively couples the motions of the plasma and the magnetic field. This inherently strong coupling means that the structure and evolution of magnetic fields (of the Sun, of the Earth, and even of the Moon itself) play an essential role in organizing and regulating the local environment of the Moon - the environment to be experienced by explorers. By working to understand, and so predict, the variations that occur from day to day, and from region to region, the productivity and overall success of future lunar robotic and manned missions can be significantly enhanced. This talk will articulate some of the viable investigations that can be pursued at the Moon that address topics of Solar and Space Physics. The content is based on a community based report in press entitled "Heliophysics Science and the Moon"

Dr. James Spann
NASA MSFC

Special Seminar: 18 Jan 2008, 10:30am, NSSTC 2096

Wed, 23 Jan 2008 08:37:33 -0600

Chandra/ACIS Observations of Massive Star Forming Regions

Much of the stellar populations inside of the massive star forming regions are poorly studied in the optical and infrared wavelengths because of observational challenges caused by large distance, high extinction, and heavy contamination from unrelated sources. High spatial resolution X-ray images have opened a new window to probe the rich intermediate-mass and low-mass young stellar populations accompanying the massive OB stars in each region. I present Chandra/ACIS observations of two massive star forming complexes, namely the NGC 6357 region and the Rosette Complex, concentrating on the new census of low-mass cluster members and new knowledge of the IMFs. These studies demonstrate the unique power of studying star formation in the X-ray band.

Dr. Junfeng Wang
Penn State

Colloquium: 15 Jan 2008, 2:30pm, OB 234

Wed, 23 Jan 2008 08:37:51 -0600

The Multi-Universe Cosmos - A New cosmological theory of the birth of the cosmos, our universe, and its fate

I propose an entirely new approach to the origin of the Cosmos and our universe, one of many in a Multi-Universe Cosmos. The new model eliminates the mysterious singularity at time 0, the origin of which and its explosion no one can explain. It is the first theory which describes the creation of the Universe using laws of physics which hold everywhere and embody the conservation law of energy. Long before any universe was born, the 4-dimensional cosmic space-time was created and all laws of physics established.

Karel Velan
Velan, Inc

Colloquium: 8 Jan 2008, 2:30pm, OB 234

Wed, 23 Jan 2008 08:38:20 -0600

Physics and Astrophysics from the Gamma-ray Large Area Space Telescope (GLAST)

GLAST is a major space observatory planned for launch by NASA in May 2008. It will explore the GeV gamma ray region of the cosmic gamma ray spectrum with fifty times the effective sensitivity of previous facilities and help investigate gamma ray bursts. It is expected to make major discoveries involving black holes, neutron stars, cosmic rays and the sun. In addition, it has the capability to detect a signal from annihilating dark matter.

Roger Blandford
Kavli Institute, Stanford University