• Thursday, May 26, 2016 - 3:30pm to 4:30pm  ·  Space Science Seminar
    Jerry Goldstein, Southwest Research Institute

    Abstract: 

  • Wednesday, May 25, 2016 - 3:00pm to 4:00pm  ·  Space Science Seminar
    Shri Kanekal, NASA Goddard Space Flight Center

    Abstract: Since the discovery of the Earth’s radiation belts by James Van Allen in the 1950s, they have been well studied providing a laboratory for understanding charged particle dynamics in the heliosphere and beyond. The Van Allen belts, comprise charged particles trapped in the geomagnetic field, usually confined to two distinct regions, the inner and the outer belt separated by the so-called slot region.

  • Wednesday, April 27, 2016 - 3:00pm  ·  Space Science Seminar
    Dr. Ningyn Liu, Florida Institute of Technlogies

    Abstract: Thunderstorms and lightning can produce strong impact on the D region (60-100 km) of the ionosphere. The most impressive display of this impact is the occurrence of transient luminous events such as sprites and halos caused by lightning. Recent studies show that the D region ionospheric density can be briefly increased by many orders of magnitude due to extremely intense lightning. On the other hand, it has also been found that moderate variation of the lower ionosphere on a timescale of minutes to hours is correlated with electrical activity in thunderstorms.

  • Wednesday, April 20, 2016 - 4:00pm to 5:00pm  ·  Space Science Seminar
    Kristopher G. Klein, UNH

    Abstract:  Characterizing the nature of the dissipation of turbulent, electromagnetic fluctuations remains a significant challenge in understanding a number of heliospheric processes, including coronal heating and the acceleration of the solar wind. A number of dissipation mechanisms have been proposed, which can be broadly classified as coherent, such as Landau, cyclotron, and transit-time damping, incoherent, such as stochastic heating, and interactions occurring in intense, spatially intermittent structures.

  • Wednesday, April 13, 2016 - 3:00pm to 4:00pm  ·  Space Science Seminar
    Dr. Eric Grove, Naval Research Laboratory

    Abstract: Since its launch in 2008, the Fermi Gamma-ray Space Telescope has revolutionized gamma-ray astrophysics, transforming our understanding of the high-energy universe.  Its primary instrument, the Large Area Telescope (LAT), surveys the gamma-ray sky above 20 MeV with a sensitivity at least a factor of 30 better than its predecessor, EGRET on the Compton Gamma Ray Observatory.  This improvement was made possible by a novel design using modern solid-state detectors and scintillators, and was realized by scientists and engineers in five countries working over a period

  • Thursday, March 31, 2016 - 3:00pm  ·  Space Science Seminar
    Brant Carlson, Carthage College in Wisconsin

    Abstract:  The conductive lightning channel is only a centimeter or so in diameter.  Charge deposited along such a narrow channel produces a large radial electric field, producing corona discharge in nearby air that carries the charge outward several meters.  The formation of this "corona sheath" affects a wide range of observable properties of lightning, including the overall charge carried by the channel, the shape, speed, and attenuation of impulsive currents, and the possibility of x-ray production.  This talk discusses such effects and introduces a simplified model of

  • Wednesday, March 23, 2016 - 3:00pm to 4:00pm  ·  Space Science Seminar
    Brian Walsh, Boston University

    Abstract: Whenever and wherever the solar wind encounters neutral atoms, soft X-rays are emitted. Charge exchange between high charge state solar wind ions and neutral atoms results in the isotropic emission of soft X-ray photons with energies from 0.1 to 2.0 keV.  This process has been observed to occur at comets, the Moon, as well as both magnetized and unmagnetized planets. Taking advantage of this emission, wide field-of-view X-ray imagers can be used to study the density structures generated by the plasma processes surrounding planets.

  • Wednesday, March 16, 2016 - 3:00pm to 4:00pm  ·  Space Science Seminar
    James O'Donoghue, Boston University

    Abstract: The upper-atmospheres of Gas Giant planets, Jupiter and Saturn, are composed of charged and neutral material that interact with space in several ways. This talk mainly focusses on the interaction between these atmospheres and the near space environment via the magnetic field of each planet. An overview of ground-based astronomy in the infrared will be presented for context, followed by a close look at the polar atmospheres of Jupiter and Saturn which exhibit powerful auroral emissions.

  • Wednesday, February 24, 2016 - 3:00pm to 4:00pm  ·  Space Science Seminar
    Alexander Drozdov, UCLA, Dept. of Earth and Space Sciences

    Abstract: The Versatile Electron Radiation Belt (VERB) code solves the Fokker-Planck equation, taking into account radial diffusion and local pitch-angle, energy and mixed scattering. Using the VERB code, we performed several long-term simulations during the first year of the Van Allen Probes mission. We considered the energetic (>300 KeV), relativistic (~1 MeV) and ultra-relativistic (>3 MeV) electrons. The measurements of the energetic and relativistic electrons were well reproduced by the simulation during a period of various geomagnetic activity.

  • Wednesday, February 17, 2016 - 3:00pm to 4:00pm  ·  Space Science Seminar
    Dr. Alexa J. Halford

    Abstract: We often find ourselves focusing on very specific topics and regions of the magnetosphere. This can be a fantastic way to advance the field’s knowledge. However, every once in awhile an event comes along which forces us to zoom back out and see the grandeur and interconnectedness of the system. I  would have thought that this experience would come for me in the form of another Carrington event [Carrington, R. C. (1859), Monthly Notices of the Royal Astronomical Society], or something like the Feb.