Auroral Kilometric Radiation is the most powerful natural radio emission from Earth's environment, carrying away up to a percent of the energy of the aurora. Our group and others have found evidence that the radiation is not only beamed away from the Earth, as previously known, but occasionally leaks to low altitudes.
[more]Electromagnetic ion cyclotron and whistler chorus waves occur in the Earth's inner magnetosphere at a distance of about 4 to 7 Earth radii from the Whistler chorus waves occur in the Earth's inner magnetosphere at a distance of about 4 to 7 Earth radii from the center of the earth. These waves are thought to provide a mechanism for energization and loss of particles in the Earth's radiation belt. Two-dimensional simulations of these waves are revealing the structure of the waves, their evolution, and their effects on particle populations including the radiation belts.
[more]BARREL uses stratospheric balloons to study the loss of high energy electrons from Earth's Van Allen radiation belts. The electrons in this region of near-Earth space are relativistic, moving very close to the speed of light. BARREL balloons measure x-rays produced by these particles when they are scattered into Earth's atmosphere. BARREL balloon campaigns have been conducted in Antarctica in January-February 2013 and 2014 during which 20 small (~20 kg) balloon payloads were launched, and in Sweden in 2015 (7 launches).
[more]Many-body quantum systems can be very difficult to handle theoretically, and in some important cases the true nature of the phase diagram is not yet accurately known. One possible path to gain deeper understanding of these incredibly rich physical systems is to engineer a "synthetic" many body quantum system that maps onto a particular system of interest, but has more conveniently tunable properties. Ultracold atoms in engineered optical potentials are one platform for such an approach.
[more]Driving a physical system abruptly through a continuous phase transition leads to a variety of interesting physical phenomena, including spontaneous formation of topological defects such as solitons, vortex lines, and monopoles. This is a universal phenomenon which is relevant to systems as diverse as ultra-cold quantum fluids and the cooling of the universe shortly after a `hot big bang'. The critical behavior of these systems is not determined by local dynamics, but rather by universal scaling laws arising from key global parameters (e.g.
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