Compressible electron flow through a narrow cavity is theoretically unstable, and the oscillations occurring during instability have been proposed as method of generating Terahertz radiation. We numerically demonstrate that endpoint this nonlinear hydrodynamic oscillator, consisting an alternating shock wave rarefaction-like relaxation flowing back forth in device. This qualitative physics robu...

We report on the first three-dimensional hydrodynamic simulations of secular and dynamical nonaxisymmetric instabilities in collapsing, rapidly rotating stellar cores which extend well beyond core bounce. The resulting gravitational radiation has been calculated using the quadrupole approximation. We find that secular instabilities do not occur during the simulated time interval of several 10ms...