A. Parisi | Searcharxiv

arXiv2017

Gravitational waves from neutron star excitations in binary inspirals

In the context of binary inspiral of mixed neutron star - black hole systems, we investigate the excitation of the neutron star oscillation modes by the orbital motion. We study generic eccentric orbits and show that tidal interaction can excite the f-mode oscillations of the star by computing the amount of energy and angular momentum deposited into the star by the orbital motion tidal forces via closed form analytic expressions. We study the f-mode oscillations of cold neutron stars using recent microscopic nuclear equations of state, and we compute their imprint into the emitted gravitational waves.

gr-qc↗

arXiv2004

Three-dimensional phase-field simulations of directional solidification

The phase-field method has become in recent years the method of choice for simulating microstructural pattern formation during solidification. One of its main advantages is that time-dependent three-dimensional simulations become feasible. This makes it possible to address long-standing questions of pattern stability. Here, we investigate the stability of hexagonal cells and eutectic lamellae. For cells, it is shown that the geometry of the relevant instability modes is determined by the symmetry of the steady-state pattern, and that the stability limits strongly depend on the strength of the crystalline anisotropy, as was previously found in two dimensions. For eutectics, preliminary investigations of lamella breakup instabilities are presented. The latter are carried out with a newly developed phase-field model of two-phase solidification which offers superior convergence properties.

cond-mat.mtrl-sci↗