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).

Wednesday, October 12, 2016 - 3:30pm to 4:00pm  ·  Space Science Seminar
Charles Farrugia, UNH

Abstract: We discuss plasma, magnetic and electric field data for a flux transfer event (FTE) to highlight improvements in our understanding of these transient reconnection signatures resulting from high resolution data. The ~20 s-long, reverse FTE, which occurred south of the geomagnetic equator near dusk, was immersed in super-Alfvenic flow.  We focus on (i) providing the first observations of field line draping of the external field around the flux rope; (ii) motivating the use of non-force free methods in modeling FTE flux ropes.