We present a comprehensive theory of the Dyakonov-Shur (DS) plasma instability in current-biased graphene transistors. Using hydrodynamic approach, we derive equations describing DS two-dimensional electron fluid at arbitrary values drift velocity. These nonlinear together with Maxwell's are used for numerical analysis spatial and temporal evolution system after is triggered by random current f...

We present a detailed temporal analysis of a set of hydrodynamic and magnetohydrodynamic (MHD) simulations of geometrically-thin (h/r ∼ 0.05) black hole accretion disks. The black hole potential is approximated by the Paczynski-Wiita pseudo-Newtonian potential. In particular, we use our simulations to critically assess two widely discussed models for high-frequency quasi-periodic oscillations, ...