Current Projects

The Expansion Kinematics of High Mass Supernovae

 Stars around 10 times or more massive than our Sun end their lives when they run out of light elements to convert into heavier elements thus making energy. When they run out of such nuclear fuel, the star's central regions collapse under the weight of the layers above, crushing the gas forming a neutron star which ironically releases more energy than the star produced during its entire lifetime. Such stellar deaths are seen as supernova outbursts. Our knowledge about many of the important details of just how the star explodes -- such as whether its spherical or bipolar -- are presently uncertain. Through a study of the kinematics of the expanding debris of several supernova remnants from high mass stars, we hope to clarify some of the physical processes behind such awesome stellar eruptions.


The Evolution of Blue Spectral Features in Late-Time Type Ia Supernova Spectra

This project is to develop a long duration, high-altitude LTA platform optimized to use solar heating to generate lift and intended to loft small payloads in the range of 5–20 kg mass. The envisioned platform is a hybrid system building upon the well-established zero-pressure balloon technology employed by NASA but adding a solar energy capture and containment element to increase the lifting capability during daylight hours. The objective is to demonstrate the utility of solar heating for such a concept. A clear demonstration of the practicality of solar hot air lift could stimulate interest among large funding agencies to pursue the solar-powered, station-keeping LTA concept.



ISINGLASS (Ionospheric Structuring: In Situ and Groundbased Low Altitude Studies)

The upcoming ISINGLASS sounding rocket mission (February 2017, Poker Flat Rocket Range, Alaska) will sample multiple locations simultaneously in the auroral ionosphere to take gradient measurements of plasma parameters. Two identical rockets will be flown into two separate events (ie, quiet early evening arc vs dynamic rayed arc); each rocket has a large subpayload, and four small deployable payloads.

An Analog Circuits Approach to Quantum Systems

This project maps the stochastic and deterministic dynamics of open and closed quantum systems to analog circuit architectures and motifs. Such motifs may then be used to both map quantum systems to analog supercomputing chips, and to design novel quantum circuits. Many common circuit themes in analog and quantum computation include noise and thermodynamics, fault tolerance, feedback control, back action and loading, entanglement and correlation, precision measurement,  nonlinear dynamics, robustness-efficiency tradeoffs, scalability,  and hybrid quantum-classical operation.

FACULTY CONTACT: Rahul Sarpeshkar

Measuring Travelling Ionospheric Disturbances Using Transmitters of Opportunity

Travelling Ionospheric Disturbances (TIDs) result from  large-scale waves in the upper atmosphere somewhat analogous to ocean waves, though propagating internal to the medium rather than on the surface. By transporting energy  they play a role in determining the temperature profile of the upper atmosphere. They also affect radio signals propagating through and beneath the ionosphere. Dartmouth students are involved in operating radio receivers in at least four sites in the northeastern United States, detecting TIDs through the small (0.1 Hz) Doppler shift that their ionospheric motions impose on reflecting AM radio signals. A goal is to determine many properties of the TIDs, including propagation directions and waveform shapes, from observed Doppler shifts at multiple locations.


Computer simulations of stellar winds interacting with the interstellar medium

Space observatories are finding more and more stars that lose some of their atmosphere in the form of a stellar wind (like our Sun’s solar wind) which interacts with the ever-present interstellar gas in such a way that bow shocks and other interaction features light up. The project focuses on simulating this stellar wind / dense interstellar gas interaction in 3D, synthesizing observables numerically, and then comparing them to the observations to explore the physics of the interaction. The project involves computer modeling (adapting an existing solar wind model) and analyzing simulation data. The prerequisite is having an affinity for using computers extensively in this way.


Characterizing the out-of-ecliptic solar wind

The focus of this project is the solar wind, a steady plasma stream of solar atmosphere lost by the Sun and blowing past the planets. Spacecraft have measured the solar wind for many decades. All but one spacecraft observe in the ecliptic plane (Earth’s orbital plane). For studies of the global heliosphere (Voyager 1, 2; IBEX), the complete 3D solar wind is needed as input, including the out-of-ecliptic solar wind. The only mission to ever measure solar wind away from the equator was Ulysses, a NASA/ESA mission (1992-2009). The Ulysses solar wind data need to be analyzed, separating their long-term behavior from short-term fluctuations, and generalized in a statistical manner in order to characterize possible, realistic 3D configurations of the solar wind. The project is dominated by computer work. The prerequisite is having an affinity for using computers extensively in this way.


Plasma Turbulence

Professor Barrett Rogers's research in theoretical and computational plasma physics addresses problems in turbulence, a ubiquitous feature of plasma systems. It can arise, for example, from non-uniformities in plasma flows, or be driven by instabilities arising from non-uniformities in the plasma density or temperatures. In magnetic fusion experiments, small-scale instabilities generate turbulence at small scales, which in turn transport plasma and heat from the core of fusion reactors to the walls. The convective losses generated in this way are among the greatest difficulties facing the design of a feasible fusion device.


Magnetic Reconnection

Professor Barrett Rogers's research in theoretical and computational plasma physics addresses problems in magnetic reconnection. Space and laboratory plasmas such as the sun, the magnetosphere, and laboratory fusion experiments often store large quantities of energy in embedded magnetic fields. Magnetic reconnection is a ubiquitous process that can convert some fraction of this energy, often explosively, into high speed flows and thermal energy. Reconnection is the fundamental process underlying cataclysmic phenomena such as coronal mass ejections, magnetospheric substorms, and "sawtooth-crash'' reconnection in tokamak fusion reactors. The rapidity of such events is often so extreme that it has been an ongoing challenge to explain theoretically. Reconnection also generates intense electric fields that can accelerate particles to very high energies.