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.

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.

Tuesday, December 22, 2015 - 11:00am to 12:00pm  ·  Space Science Seminar
Drew Turner, Aerospace Corporation

Earth’s radiation belts were the first major scientific discovery from satellite observations in the Space Age, but despite decades of research, there are still many unanswered questions concerning the nature of these energetic particle populations. With the recent launch of NASA’s Van Allen Probes spacecraft adding to the fleet of science missions in Earth’s magnetosphere, we are now in a “golden era” of radiation belt research.