Bulletin of the American Physical Society
APS April Meeting 2015
Volume 60, Number 4
Saturday–Tuesday, April 11–14, 2015; Baltimore, Maryland
Session R2: Solar System |
Hide Abstracts |
Sponsoring Units: DAP Room: Holiday 1 |
Monday, April 13, 2015 10:45AM - 10:57AM |
R2.00001: Solar-Heliospheric-Interstellar Cosmic Ray Tour with the NASA Virtual Energetic Particle Observatory and the Space Physics Data Facility John F. Cooper, Natalia E. Papitashvili, Rita C. Johnson, Nand Lal, Robert E. McGuire NASA now has a large collection of solar, heliospheric, and local interstellar (Voyager 1) cosmic ray particle data sets that can be accessed through the data system services of the NASA Virtual Energetic Particle Observatory (VEPO) in collaboration with the NASA Space Physics Data Facility SPDF), respectively led by the first and last authors. The VEPO services were developed to enhance the long-existing OMNIWeb solar wind and energetic particle services of SPDF for on-line browse, correlative, and statistical analysis of NASA and ESA mission fields, plasma, and energetic particle data. In this presentation we take of tour through VEPO and SPDF of SEP reservoir events, the outer heliosphere earlier surveyed by the Pioneer, Voyager, and Ulysses spacecraft and now being probed by New Horizons, and the heliosheath-heliopause-interstellar regions now being explored by the Voyagers and IBEX. Implications of the latter measurements are also considered for the flux spectra of low to high energy cosmic rays in interstellar space. [Preview Abstract] |
Monday, April 13, 2015 10:57AM - 11:09AM |
R2.00002: A Causal, Covariant Theory of Dissipative Fluid Flow Dillon Scofield, Pablo Huq The use of newtonian viscous dissipation theory in covariant fluid flow theories is known to lead to predictions that are inconsistent with the second law of thermodynamics and to predictions that are acausal. For instance, these problems effectively limit the covariant form of the Navier-Stokes theory (NST) to time-independent flow regimes. Thus the NST, the work horse of fluid dynamical theory, is limited in its ability to model time-dependent turbulent, stellar or thermonuclear flows. We show how such problems are avoided by a new geometrodynamical theory of fluids (GTF, Fluid Dynamics Research, 46, 055513,14 (2014)). This theory is based on a recent result of geometrodynamics showing current conservation implies gauge field creation, called the vortex field lemma (VFL, Phys. Lett., A 374, 3476-82 (2010)) and classification of flows by their Pfaff dimension. Experimental confirmation of the theory is reviewed. [Preview Abstract] |
Monday, April 13, 2015 11:09AM - 11:21AM |
R2.00003: The Common-origin of Kinetic Turbulence and Electron-Halo of Velocity Distribution Function in the Solar Wind Haihong Che Observations of solar wind show that the power spectra of magnetic fluctuations break from Kolmogorov scaling law at ion inertial length. In addition, the electron velocity distribution function of solar wind exhibits an isotropic halo. What causes the spectral break and electron halo are two puzzles in heliophysics. I present a new model (Che et al., PRL,112, 2014 and ApJL, 795, 2014) that accounts for both puzzles---the kinetic turbulence and electron halo of solar wind originate from the nanoflare-accelerated keV electron beams in the inner corona. With PIC simulations, we found that the keV electron beams drive strong two-stream instabilities. The nonlinear evolution of the two-stream instability gives rise to an isotropic electron halo, kinetic Alfvenic wave and whistler wave turbulence through forward and inverse energy cascades.The most important predictions of this model include: 1) the energy injection plateau in the magnetic power spectra; 2) the enhanced parallel electrostatic fluctuation in the solar wind; 3) the core-halo relative drift, a relic of the saturated two-stream instability; 4) the temperature ratio of core-halo is determined by the two-stream instability heating property and the core-halo density ratio. The generation of Langmuir waves can produce type III micro-radio bursts that resemble the well-studied type III bursts observed in solar flares. [Preview Abstract] |
Monday, April 13, 2015 11:21AM - 11:33AM |
R2.00004: Atmospheric Ionization Measurements Thomas Slack, Riley Mayes The measurement of atmospheric ionization is a largely unexplored science that potentially holds the key to better understanding many different geophysical phenomena through this new and valuable source of data. Through the LaACES program, which is funded by NASA through the Louisiana Space Consortium, students at Loyola University New Orleans have pursued the goal of measuring high altitude ionization for nearly three years, and were the first to successfully collect ionization data at altitudes over 30,000 feet using a scientific weather balloon flown from the NASA Columbia Scientific Ballooning Facility in Palestine, TX. In order to measure atmospheric ionization, the science team uses a lightweight and highly customized sensor known as a Gerdien condenser. Among other branches of science the data is already being used for, such as the study of aerosol pollution levels in the atmosphere, the data may also be useful in meteorology and seismology. Ionization data might provide another variable with which to predict weather or seismic activity more accurately and further in advance. Thomas Slack and Riley Mayes have served as project managers for the experiment, and have extensive knowledge of the experiment from the ground up. [Preview Abstract] |
Monday, April 13, 2015 11:33AM - 11:45AM |
R2.00005: Geant4 Simulation of the Relativistic Runaway Electron Avalanche Process and Terrestrial Gamma ray Flashes S.T. Alnussirat, J.W. Watts, G.J. Fishman, H.J. Christian Terrestrial Gamma-ray flashes (TGFs) are energetic pulses of photons, which are short and intense, originating in the atmosphere during thunderstorm activity. Despite the variety of observations, understanding the mechanisms that generate TGFs have lagged behind. Two mechanisms have been suggested as a source of the TGFs: (1) The Relativistic Runaway Electron Avalanche (RREA) process with the FeedBack mechanism, and (2) the lightning leader mechanism. Using different Electro-Magnetic (EM) processes and electric fields implemented in Geant4, we have simulated the RREA and Feedback Mechanism. The avalanche rate and photon spectra of different EM processes will be presented and discussed. [Preview Abstract] |
Monday, April 13, 2015 11:45AM - 11:57AM |
R2.00006: Laboratory studies on the rheology of cryogenic slurries with implications for icy satellites Elizabeth Carey, Karl Mitchell, Mathieu Choukroun, Fang Zhong Interpretation of Cassini RADAR and VIMS data has suggested some landforms on Titan may be due to effusive cryovolcanic processes that created cones, craters and flows [1]. High-resolution Voyager 2 images of Triton also show strong evidence of cryovolcanic features [2]. Fundamental to modeling of cryovolcanic features is the understanding of the rheological properties of cryogenic icy slurries in a thermodynamic and fluid mechanical context, i.e., how they deform and flow or stall under an applied stress. A series of measurements were performed on methanol-water mixtures and ammonia-water mixtures. We measured the rheology of the slurries as a function of temperature and strain rate, which revealed development of yield stress-like behaviors, shear-rate dependence, and thixotropic behavior, even at relatively low crystal fractions. Visualization of icy slurries supports the current hypothesis that crystallization dominates rheological properties. We shall discuss these findings and their implications for cryovolcanism on icy satellites. \\[4pt] [1] Lopes, R. M. C., et al., 2013. Cryovolcanism on Titan: New results from Cassini RADAR and VIMS. J. Geo. Res. 118, 416-435.\\[0pt] [2] Smith, B. A., et al., 1989. Voyager 2 at Neptune: Imaging science results. Science 246, 1422-1450. [Preview Abstract] |
Monday, April 13, 2015 11:57AM - 12:09PM |
R2.00007: New trans-Neptunian Objects in the Dark Energy Survey Supernova Fields David Gerdes The Dark Energy Survey (DES) observes ten separate 3 sq. deg. fields approximately weekly for six months each year. Although intended primarily to detect Type Ia supernovae, this data set provides a rich time series that is well suited for the detection of objects in the outer solar system, which move slowly enough that they can remain in the same field of view for weeks, months, or even across multiple DES observing seasons. With ecliptic latitudes ranging from -15 to -45 degrees, DES is particularly sensitive to the dynamically hot population of Kuiper Belt object, as well as detached/inner Oort cloud objects. Here I report the results of a search for new trans-Neptunian objects in the first two seasons of DES data. The objects discovered to date include a new Neptune trojan, a number of objects in mean motion resonances with Neptune, an object with an orbital inclination of 48 degrees, and several distant scattered disk objects including one with an orbital period of nearly 1200 years. I will also discuss prospects for extending the search to the full 5000 sq. deg. DES wide survey. [Preview Abstract] |
Monday, April 13, 2015 12:09PM - 12:21PM |
R2.00008: Of the nature of a hot, ``strongly-''magnetized plasma state -in thermal equilibrium- in astrophysics Daniel Berdichevsky The main outcome of this study of constitutive properties of the medium is the estimation of its magnetic permeability, two orders of magnitude smaller than that of the vacuum, i.e., a highly diamagnetic material. (This diamagnetic property is consistent with the superconductivity assumption in magnetohydrodynamics theory, baseline of any macroscopic-scale description of the interplanetary medium.) We propose that a 3-D amorphous Langmuir lattice state is a good representation of the properties of this class of self-organized magnetized matter in solar transients, coronal mass ejections, containing extremely dilute matter strongly dominated by a magnetic field. We further conjecture that the presented state of magnetized matter could be an adequate representation of the `local insterstellar medium region,' in which the solar-system as a whole moves, based on current observations by the spacecraft Voyager 1. The presented interpretation benefits from the observation of many strongly magnetized structures ejected by the Sun, in their march through the interplanetary space evolving consistently with a simple 3-D magnetohydrodynamic model representation.\footnote{Berdichevsky, D. B., \textit{Sol. Phys., }DOI 10.1007/s11207-012-0176-5. \textit{Sol. Phys., }\textbf{284}, 245-259, 2013.} Understanding of the magnetized matter state is gained by means of a case study from 3s in-situ magnetic field and plasma observations in space, which will be outlined in the presentation.\footnote{Berdichevsky, D. B., and K. Schefers, submitted to \textit{ApJ, 2014.}} (These are SWE and MFI instruments data in spacecraft Wind.) [Preview Abstract] |
Monday, April 13, 2015 12:21PM - 12:33PM |
R2.00009: A Detection of the Gamma-Ray Albedo of Solar System Bodies Yuexia Lin, Manel Errando, Reshmi Mukherjee Interactions of cosmic rays with solar system bodies (SSBs) produce an albedo gamma-ray emission via processes such as pion decay. The albedo emission has been detected from the Sun and the Moon. It is also possible to find emissions from other SSBs that are smaller or farther away from the Earth. The gamma-ray albedo of small SSBs, such as asteroids in the Main Belt, can provide an indirect measurement of the number and size distribution of those small SSBs below the detection limit of other methods. We analyze more than 6 years of all sky data from Fermi Large Area Telescope (LAT), looking for an excess of gamma-ray emission at low ecliptic latitudes. Our methods include subtracting emissions from the Galactic plane and known sources in LAT 2-year Point Source Catalog. The sensitivity of this analysis exceeds that of the previous study using Energetic Gamma-Ray Experiment Telescope (EGRET) data (Moskalenko \textit{et al.}, 2008), which can lead to better limits of the celestial gamma-ray foreground. We will present results from our analysis. [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