Bulletin of the American Physical Society
2008 Joint Spring Meeting of the Texas Sections of APS, AAPT, and Zone 13 of SPS
Volume 53, Number 1
Thursday–Saturday, March 6–8, 2008; Corpus Christi, Texas
Session APS2: Astrophysics, Space Physics, Astronomy and Cosmology |
Hide Abstracts |
Chair: Shaukat Goderya, Tarleton State University Room: Omni Corpus Christi Hotel Marina Tower Riviera I |
Friday, March 7, 2008 10:30AM - 10:42AM |
APS2.00001: Ultraviolet Radiation on the Early Earth Billy Quarles What gave life the initial spark? Some mythical force that governs all or some natural reaction that was a product of the conditions of environment set in place by physics. There is still much debate, but our search is in a more academic environment. The evolution of the Sun could be an indicator to how the atmosphere has evolved to accommodate life. In the early era of the Earth we do know from other sources that there was no oxygen or ozone to help support life. What made life possible under such harsh conditions. The answer to this inquiry can be found by knowing the UV flux from the Sun during this time period. [Preview Abstract] |
Friday, March 7, 2008 10:42AM - 10:54AM |
APS2.00002: Analysis of the Viscous Potential Determined from MHD Simulations and Comparisons to Observations and a Model Robert Bruntz, Ramon Lopez The viscous potential in Earth's ionosphere is produced by a mechanical interaction between the magnetosphere and the solar wind. It is generally taken to have a value of between 10 and 40 kV and either be constant or depend only on solar wind velocity. Investigations using the Lyon-Fedder-Mobarry global MHD simulation indicate that the viscous potential increases with both increasing solar wind velocity and increasing density, as does a recent model by Newell et al. Empirical data can be inferred from measurements of the transpolar potential by DMSP satellites during intervals when the ionospheric potential due to merging with the solar wind should be extremely small, assuming that the potential is driven primarily by the viscous interaction. This study will compare the LFM results to the Newell et al. model and to the DMSP observations. [Preview Abstract] |
Friday, March 7, 2008 10:54AM - 11:06AM |
APS2.00003: Effects of Solar Wind Density on Geo-effectiveness of Storms Elizabeth Mitchell, Ramon Lopez Geomagnetic storms are produced by solar wind disturbances causing large currents to flow throughout the magnetosphere. One current system observed to form during geomagnetic storms is the Ring Current. The rate of ring current injection is used to measure the geo-effectiveness of the solar wind electric field. Examining the relationship between the solar wind electric field and the ring current injection rate, we have found a dependence on the Alfv\'{e}n Mach number during periods when the solar wind electric field has a non-linear relationship with the transpolar cap potential. During these periods, known as saturation, an increase in the Alfv\'{e}n Mach number relates to a greater ring current injection rate for the same amount of solar wind electric field. Since the Alfv\'{e}n Mach number depends on the solar wind density, this effect indicates that the geo-effectiveness of the solar wind electric field depends on the solar wind density as well as its electric field when the transpolar cap potential is saturated. [Preview Abstract] |
Friday, March 7, 2008 11:06AM - 11:18AM |
APS2.00004: Laser Driven Radiative Shocks in High Energy Density C. Manka, R. Lunsford, S. Nikitin, M. Laming, D. Zabatakis, J. Grun The long time over which oscillations associated with radiative shocks within the interstellar medium occur makes direct observation of these instabilities highly problematic. A velocity dependant cooling instability is thought to cause fluctuations in the propagation velocity of such shocks. An experiment at NRL investigates and perhaps validates the applicability of present analytic models to various multidimensional radiative shock instabilities. The PHAROS laser at NRL is used to create the relevant shock front by ablative acceleration of an aluminized Mylar foil that covers a small gas filled tunnel in a PMMA block. As this shock propagates along the tunnel, a secondary shock is launched into the walls of the tunnel and the progress of this shock into the PMMA block preserves a continuous record of the primary shock's velocity as it travels the length of the tunnel. The density gradient associated with the shock in the PMMA is recorded using dark field shadowgraphy on a SIM-8 multi-channel high speed framing camera. The tunnel shock velocity is determined from the shape of the shock launched into the PMMA block for any time prior to the instant at which the image frame was taken, providing documentation of any oscillations in the velocity of the shock. [Preview Abstract] |
Friday, March 7, 2008 11:18AM - 11:30AM |
APS2.00005: Ionospheric Skill Scores in TING Jorge Landivar, Alan Burns, Ramon Lopez This presentation examines two ionospheric models, Themosphere-Ionosphere Nested Grid (TING) and International Reference Ionosphere (IRI), and compares them to each other and to ionosonde data from the SPIDR database for the time period of July 1995 from the 4th through the 16th, by calculating standard skills scores. This presentation is a follow-up to a previous Texas APS meeting presentation. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700