Poster presentation

Space Science Seminar

  • Wednesday, October 18, 2017 - 3:00pm to 4:00pm  ·  Space Science Seminar
    Caitano L. da Silva, Ph.D., Dartmouth College

    Abstract:  Mechanisms of relativistic electron acceleration in plasmas are a subject of intense investigation. Some interesting examples are: unsteady magnetic reconnection in the solar wind leading to betatron and Fermi acceleration, runaway electron beam instabilities in tokamaks, and relativistic acceleration in the wakefields of high-power lasers. This talk briefly describes two research projects at Dartmouth aimed at understanding electron acceleration in atmospheric and space plasmas.

  • Wednesday, October 11, 2017 - 3:00pm to 4:00pm  ·  Space Science Seminar
    Dr. Geoff McHarg, United States Air Force Academy

    Abstract:  Streamers and leaders are the basic building blocks of electrical discharges found both in the laboratory and in nature.  A fundamental difference between streamers and leaders are that streamers do not deposit as much energy to the surrounding environment as leaders.  This difference is readily observable in the spectra generated from both streamers and leaders.   Streamers observed in the middle atmosphere located above positive cloud to ground lightning strikes are referred to as sprites.

  • Monday, October 2, 2017 - 3:00pm to 4:00pm  ·  Space Science Seminar
    Dr. Amanda Madden, Los Alamos National Laboratory

    Abstract:  Los Alamos National Laboratory was established in 1943 as part of the Manhattan Project, attracting scientists, mathematicians, and engineers with a single common goal: to develop the world’s first nuclear weapon. Today, a rich variety of research programs support the Laboratory’s basic mission: to solve national security challenges through scientific excellence. These programs span space science, nanotechnology, plasma physics, high performance computing, material sciences, nuclear physics and beyond.

  • Thursday, April 6, 2017 - 11:00am to 12:00pm  ·  Space Science Seminar
    Dr. Toshi Nishimura, Boston University

    Abstract: Duskside plasma convection is often enhanced at narrow latitudes just equatorward of the electron auroral oval (subauroral polarization streams or SAPS). The latitudinal extent of the flows can occasionally become less than a degree with the peak speed exceeding a few km/s. Those are called subauroral ion drifts (SAID), and their formation mechanism and differences from SAPS have been key issues in subauroral magnetosphere-ionosphere coupling.

  • Wednesday, February 22, 2017 - 3:00pm to 4:00pm  ·  Space Science Seminar
    Matthew Argall, UNH

    Abstract: Magnetic reconnection involves the conversion of electromagnetic energy into particle kinetic energy. This energy conversion begins at the electron scale, which was largely inaccessible to direct satellite observations before the Magnetospheric Multiscale (MMS) mission. MMS, launched in March, 2015, consists of four satellites in a tetrahedron formation with mean separation of as little as 7 km, or 2-3 electron skin depths at the magnetopause. It captures full 3D distribution functions of ions every 150ms and of electrons every 30ms.

  • Wednesday, February 8, 2017 - 3:00pm to 4:00pm  ·  Space Science Seminar
    Dr. Jichun Zhang, UNH

    Abstract:  Electromagnetic ion cyclotron (EMIC) waves play an important role in the overall dynamics of the Earth’s magnetosphere. Particularly, these waves contribute to the energization and loss of magnetospheric particles. For instance, EMIC waves can interact with relativistic electrons in the radiation belts as well as energetic ions in the ring current, resulting in rapid scattering loss.

  • Wednesday, November 30, 2016 - 3:00pm to 4:00pm  ·  Space Science Seminar
    Prof. Kaijun Liu, Auburn University

    Abstract: Fast magnetosonic waves are enhanced waves at frequencies close to the proton cyclotron frequency and its harmonics (up to the lower hybrid frequency) observed near the geomagnetic equator in the terrestrial magnetosphere. They can pitch-angle scatter as well as energize radiation belt electrons. The waves arise from the ion Bernstein instability driven by ring-like proton velocity distributions with a positive slope with respect to the perpendicular velocity (∂f(v_perp)/∂v_perp>0).

  • Wednesday, November 9, 2016 - 3:00pm to 4:00pm  ·  Space Science Seminar
    Daniel Verscharen, UNH

    Abstract: The solar wind is a magnetized plasma that exhibits turbulent fluctuations on many scales. In addition to the non-compressive Alfvénic component of the turbulence, a compressive component with slow-mode-like polarization is commonly observed. These fluctuations are associated with characteristic spatio-temporal changes in the particle distribution functions. If the amplitude of the turbulent fluctuations is large enough, the moments of the fluctuating distribution functions cross the thresholds for various kinetic micro-instabilities.

  • Wednesday, November 2, 2016 - 3:00pm to 4:00pm  ·  Space Science Seminar
    Naomi Maruyama, NOAA
  • Wednesday, October 26, 2016 - 3:00pm to 4:00pm  ·  Space Science Seminar
    Doug Cramer, UNH

    Abstract: Narrow flow bursts in the plasma sheet have been found to be responsible for the majority of plasma injected into the inner magnetosphere. We examine the character and behavior of these flow bursts during geomagnetic storm and quiet times using a global magnetosphere MHD model (OpenGGCM) that is coupled to a kinetic ring current model (Rice Convection Model).