Department of Physics
SCHEDULED EVENTS (2000-01)
OTHER IMPORTANT DATES
The purpose of this meeting is to discuss various matters of concern to students and faculty, e.g., colloquia, GRE, SPS, WOP, APS, LPW, Bjorklunden, letters of recommendation, the Senior Capstone program, ... All physics majors are expected to attend this meeting.
Tu 24 Oct 11:10 AM NS-102: Science Colloquium (Refreshments at 11:00 AM)
Global COOLING in the Earth's Upper Atmosphere: Why? and Should We Care?
Over the last century there have been increasing amounts of carbon dioxide and other "greenhouse" gases released into the atmosphere. These gases trap infrared radiation, thus contributiing to the problem of "Global Warming" in the lower atmosphere. In the upper atmosphere, more than ten miles above the earth's surface, however, carbon dioxide acts as a coolant. Thus the build-up of this gas substantially lowers temperatures in the upper atmosphere. Cooling in the upper atmosphere does not reduce the effect of "Global Warming". The reason for this cooling, recent evidence for it, and how it can affect us will be discussed.
Tu 24 Oct 3:00 PM NS-230: Physics/Chemistry Colloquium (Refreshments at 2:30 PM)
Molecule Formation in Dilute, Dust-poor Environments: The Early Universe and the Ejecta of Supernovae
Molecules have been found to exist in a number of astrophysical environments that at first glance would appear hostile to their formation and survival. Molecule formation in regions of low density, negligible amounts of dust, and strong radiation fields takes place primarily through two-body association reactions. One must look to theory to provide rate coefficients and cross sections for this class of reactions, as very few reliable laboratory measurements exist. I will focus on the process of radiative association, giving examples of molecules formed in the Early Universe and in the ejecta of supernovae.
Trapping a Pure Electron Plasma in a Toriodal Magnetic Field, Derek Jon Thuecks, LU '02
Measuring Charge Density in a Toriodal Pure Electron Plasma, Robin Lynn Sampson, LU, '02
Measurements of Fine and Hyperfine Splittings in Rb Via Multi-Step Excitation, Michael Keith Yakes, LU, '01
Dynamics of Vortices in BEC, Cindy Anne Regal, LU '01
Cindy Regal is a senior physics major at Lawrence who spent last summer working on Bose-Einstein Condensation ("BEC") in the laboratory of Dr. Eric Cornell of the Joint Institute of Laboratory Astrophysics at the University of Colorado-Boulder. To achieve BEC and examine some of its various properties, Regal, Cornell, and associates cool and optically trap their rubidium or cesium vapors at nanoKelvin temperatures where many exotic effects and properties of the vapors become manifest. Ms. Regal will discuss some of the bizarre and intricate properties of vortices created in Bose-Einstein condensates. Ms. Regal is a Claire Booth Luce and Barry M. Goldwater Scholar.
What'n the Heck's Goin' On: An Analysis of the OptoTrak Measurement System,
Joshua David Cross, Department of Physics, Lawrence University (Mr. Cross spent the summer of 2000 working at the NASA Langley Research Center. In this talk, he will report on that work.)
The OptoTrak Measurement System is an integrated infrared camera system and software package that is being developed for possible use at NASA Langley. The system is unlike traditional camera systems in that it uses active infrared markers to track rigid body orientation in six dimensions. There are multiple aspects of the system, however, that complicate what is otherwise supposed to be a very straightforward application. My research this summer involved the investigation of some of the complicating factors of the OptoTrak system. Some of the critical issues dealt with were: system calibration, rigid body definition, model curvature, and coordinate system transformations.
The scientific talk will be followed by a 5-10 minute overview of "Life at Langley: Why living in VA isn't so bad if you get up early, don't mind traffic, and think that an outdoor sauna is a good idea."
Fusion Energy: Promise, Characteristics, Status, and the Future, Professor James D. Callen, Department of Engineering Physics, University of Wisconsin-Madison.
Professor Callen will be here for much of the day and would like to meet with any students who are interested in the engineering physics program at Madison. He will, in particular, be joining us for tea in the late afternoon.
Find the Hole: Locating Positive Ion Vacancies in Paramagnetic Crystals
Jaques Bluett, Department of Physics, Lawrence University
Electron Paramagnetic Resonance (EPR) Spectroscopy allows one to probe the inner structure of species containing unpaired electrons. Probing the effect of Cr3+ ions in an MgO crystal lattice determines the location of V centers in the lattice structure. Anisotropy in the Landé g-value allows one to make these determinations. (This talk is a report on a capstone project carried out this fall under the direction of Professor Collett.)
Strong Zonal Winds Driven by Deep Cnvection in The Giant Planets
Jonathan M. Aurnou, Department of Terrestrial Magnetism, Carnegie Institute of Washington
The dominant circulation on the giant planets is a system of zonal winds. Both Jupiter and Saturn have strong eastward jets in the equatorial region, and a pattern of alternating east-west winds at higher latitudes. Despite years of ground- and space-based observations, the origin of these zonal jets remains uncertain. After reviewing the basic dynamics of rotating convection, the results of numerical simulations of thermal convection in a rapidly-rotating spherical shell will be presented. In these simulations the zonal winds are eastward in the equatorial regions and westward at higher latitudes, and are driven by Reynolds stresses associated with the convection. These numerical results indicate that the equatorial jets seen on Jupiter and Saturn may be produced by convection deep within the atmospheres of those planets.
Superstring theory, Columbia University Professor Brian Greene's field of research, has the potential to comprehensively explain the origins of the four fundamental physical forces in the universe. Greene writes, "One of the strangest features of superstring theory is that the theory requires the universe to have more than three spatial dimensions. Much of my research has focused on the physical implications and mathematical properties of these extra dimensions ...." (More Information)
Th 11 Jan 11:10 AM Chapel: Convocation
What is String Theory?
Th 11 Jan 2:00 PM New Science Building 102
Space and Time Since Einstein
Prof. Greene will discuss some contemporary views of space and time, especially in relation to relativity, quantum mechanics, and strings. There will be opportunity for questions and discussion after the talk.
Corporate Funding for Science Research at Universities: A Joint Panel Discussion on Ethical and Other Issues
Professors Corry Azzi (Economics), Jeffrey Collett (Physics), John Dreher (Philosophy), and Rich Summers (Chemistry); moderator Rob Noll (Chemistry).
Probing a Pure Electron Plasma, Angela J. Kopp, LU '01
Angela Kopp is a senior physics major at Lawrence who worked in the summer of 1999 in Professor Stoneking's plasma laboratory and has this year conducted a capstone project in plasma physics. In her talk, she will discuss an investigation of thermal corrections to the vacuum diode I-V curve. Ms. Kopp is a Barry M. Goldwater Scholar.
Investigations of Microstructure in Electronic Materials: A Few Examples
Dr. Susan Babcock, Associate Professor of Materials Science and Engineering, University of Wisconsin--Madison.
A Materials Science View of Recent Advances in High T-c Superconductivity
Dr. Susan Babcock, Associate Professor of Materials Science and Engineering, University of Wisconsin--Madison.
Liquid Crystals with a Twist
Joshua Cross, LU '01
Predicting Armageddon: Tracking Asteroid Orbits
Joshua Vande Hey, LU '01
Science Opportunities with NASA's Space Infrared Observatory Facility (SIRTF)
Robert D. Gehrz, Professor of Astronomy and President of the American Astronomical Society, University of Minnesota, Minneapolis, MN (Dr. Gehrz's visit is supported by the Harlow Shapley Visiting Lecturer Program of the American Astronomical Society.)
To grasp the wonders of the cosmos, and its infinite variety and splendor, we must collect and analyze radiation emitted by phenomena throughout the entire electromagnetic (EM) spectrum. Towards that end, NASA proposed the concept of Great Observatories, a series of four space-borne observatories designed to conduct astronomical studies over many different wavelengths. The first three observatories are the Hubble Space Telescope, the Compton Gamma-Ray Observatory, and the Chandra X-Ray Observatory. The Space InfraRed Telescope Facility (SIRTF) represents the fourth and final element in NASA's Great Observatory program. The Space InfraRed Telescope Facility (SIRTF) is a space-borne, cryogenically-cooled infrared observatory capable of studying objects ranging from our Solar System to the distant reaches of the Universe. Once launched in Mid 2002, SIRTF will fill in an important gap in wavelength coverage not available from the ground -- the thermal infrared.
Th 31 May 11:10 AM NSB 202, Physics Colloquium
Infrared Studies of the Winds of Evolved Stellar Systems
Dr. Robert D.~Gehrz
Fine and Hyperfine Structure in the 4-2F State of Rubidium
Cindy Regal, LU '01
Layer by Layer Freezing of Liquid Crystal Films
Stuart Schmitt, LU '01
Photo Shoot: 4:10 outside Downer Commons Faculty members, seniors and juniors leaving for engineering schools should meet on the Downer steps for the taking of this traditional photo.
Annual Reception for physics graduates and their graduation guests.