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Full-Text Articles in Physics

Measuring And Modeling The Conductivity Of Highly Insulating Materials, David King Aug 2017

Measuring And Modeling The Conductivity Of Highly Insulating Materials, David King

Senior Theses and Projects

Satellites and other spacecraft must be able to withstand hazardous conditions in order to be viable in their expected operating environments. One specific hazard that occurs due to incident radiation is spacecraft charging. Insulating materials, frequently used in spacecraft and other electrical equipment, while very good at preventing charge flow, also store charge very well. This can create problems; specifically, “if the charge decay time exceeds the orbital period, not all charge will be dissipated before orbital conditions act again to further charge the satellite. As the insulator accumulates charge, the electric field will rise until the insulator breaks down” …


Relaxation Of Charge In Monolayer Graphene: Fast Nonlinear Diffusion Versus Coulomb Effects, Eugene B. Kolomeisky, Joseph P. Straley Jan 2017

Relaxation Of Charge In Monolayer Graphene: Fast Nonlinear Diffusion Versus Coulomb Effects, Eugene B. Kolomeisky, Joseph P. Straley

Physics and Astronomy Faculty Publications

Pristine monolayer graphene exhibits very poor screening because the density of states vanishes at the Dirac point. As a result, charge relaxation is controlled by the effects of zero-point motion (rather than by the Coulomb interaction) over a wide range of parameters. Combined with the fact that graphene possesses finite intrinsic conductivity, this leads to a regime of relaxation described by a nonlinear diffusion equation with a diffusion coefficient that diverges at zero charge density. Some consequences of this fast diffusion are self-similar superdiffusive regimes of relaxation, the development of a charge depleted region at the interface between electron- and …