Bulletin of the American Physical Society
2012 Annual Fall Meeting of the APS Prairie Section
Volume 57, Number 14
Thursday–Saturday, November 8–10, 2012; Lawrence, Kansas
Session G1: Astrophysics, Cosmology and Space Science III |
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Chair: Hume Feldman, University of Kansas Room: Oread Hotel Hancock Room |
Saturday, November 10, 2012 8:30AM - 8:42AM |
G1.00001: Ions in the Plume of Enceladus and the Role of Grain Interactions Sriharsha Pothapragada, Thomas Cravens, Nataly Ozak, Mih\'aly Hor\'anyi, Sascha Kempf, Geraint Jones Data from instruments aboard the Cassini Orbiter indicate plumes of neutral gas and ice from the southern polar region on the Saturn's moon, Enceladus. Flyby missions through the plumes have measured plasma (both electron and ion) conditions and composition in addition to the magnetic field. INMS measurements point to H$_{3}$O$^{+}$ as the dominant ion species through rapid reaction of H$_{2}$O$^{+}$, OH$^{+}$, and O$^{+}$ species with neutral H$_{2}$O. CAPS has reported presence of both positive and negative ions along with measured water cluster ions. We present results from Monte Carlo/test particle simulations to model the ion distribution for different species in the Enceladus plumes. We have incorporated previously proposed models of the plume / atmosphere density and plasma flow around the satellite. Effects of charge exchange, photo-ionization and dust-grain collisional ionizations by the electron and ion distributions are included in the models. We aim to interpret Cassini data by understanding the contributions of each of these effects on the observed ion, neutral and electron fluxes. [Preview Abstract] |
Saturday, November 10, 2012 8:42AM - 8:54AM |
G1.00002: Auroral Charged Particle Precipitation and Acceleration at Jupiter, Saturn, and Titan Thomas Cravens, Nataly Ozak A brief review of energetic ion interaction with the upper atmospheres of Jupiter, Saturn, and Titan will be given. Jupiter's aurora is a powerful source of radio, infra-red, visible, ultraviolet (UV), and x-ray emission. X-ray emissions with a total power of about 1 GW were observed by the Einstein Observatory, the Roentgen satellite (ROSAT), Chandra X-ray Observatory (CXO), and XMM-Newton Observatory. Most of the x-ray power is in soft x-ray emission from the polar caps, but some harder x-ray emission from the main auroral oval was also observed by the XMM Newton X-ray observatory and is probably due to electron bremsstrahlung emission. Jovian x-ray emission provides the main evidence that auroral energetic ion acceleration and precipitation is taking place at Jupiter. X-ray emission also comes from lower latitudes but is not due to particle precipitation. An ultraviolet aurora has also been observed at Saturn, due to electron precipitation. No x-ray aurora has been observed although one was expected. Saturn's satellite Titan is also subject to energy deposition from energetic electrons and ions from Saturn's magnetosphere and this will also be discussed. [Preview Abstract] |
Saturday, November 10, 2012 8:54AM - 9:06AM |
G1.00003: Final state sensitivity in magnetotail-like magnetic fields Richard Martin, Daniel Holland, Connor Brennan, Jamie Svetich In this paper we examine chaotic scattering of charged particles in magnetotail-like fields in the Earth's magnetosphere. We focus on two field models: the modified-Harris current sheet and a two-dimensional magnetic neutral line. Both of these Hamiltonian systems exhibit chaotic scattering over a wide range of parameter values. In the current sheet there is a well defined energy resonance that governs the dynamics, and we show that the neutral line model has no such resonance. We investigate self-similar behavior regarding the final state exit region when particles are injected far from the field reversal region, and show that the current sheet scattering has a fractal exit basin boundary structure that closely follows the energy resonance. The neutral line model has a more complex final state structure, which does indicate self-similarity, with a fractal structure to be determined. [Preview Abstract] |
Saturday, November 10, 2012 9:06AM - 9:18AM |
G1.00004: Mini-Tunka Kate Orr Tunka is a 133-antenna array whose purpose is to detect particle showers and measure Cherenkov light. Mini-Tunka is an attempt to re-create the Tunka experiment locally and on a smaller scale for the detection of cosmic ray muons. From the measurements I will attempt to determine the nature of the primary cosmic rays and, in the process, hopefully resolve some anomalies in the Tunka data. Ultimately the study of Cherenkov radiation will aid in the study of other much higher energy cosmic rays. Mini-Tunka is on-going and I will be discussing the process of setting up the experiment, from hardware to the search for a suitable location, and the process of muon detection and how it can be used to determine characteristics of the primary cosmic rays, such as direction fo approach and energy. [Preview Abstract] |
Saturday, November 10, 2012 9:18AM - 9:30AM |
G1.00005: Preliminary work for developing a Method for Surface Wave Detection Andrew Johannesen, Amy Zheng It is theoretically possible to improve current methods of ultra-high energy neutrino detection by observing askaryan radiation via dielectric-dielectric surface waves rather than bulk waves. The purpose of our research was to observe properties of these surface waves within the paradigm of neutrino detection. Observations were made of waves propagating through various dense dielectric mediums including granulated fused silica, polystyrene foam, deionized water, and granulated sodium chloride at preliminary frequencies of 1500, 1000, and 750 MHz. Larger scale granulated fused silica measurements were taken at the frequencies of 600 and 300 MHz. Limited experimental result would indicate a qualitative increase in attenuation length for radio frequency waves propagating along a dielectric-dielectic surface rather than exclusively in either dielectric substance. Further investigation should be in the far-field, substantially lower frequency, and in the context of the surface layer between ice and air. [Preview Abstract] |
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