A Shallow Water Analogue of the Standing Accretion Shock Instability: Experimental Demonstration and Two-Dimensional Model

TL;DR

This paper presents a laboratory experiment using shallow water to simulate and demonstrate the hydrodynamical instability known as the Standing Accretion Shock Instability, providing insights into neutron star formation.

Contribution

It introduces the first experimental shallow water analogue of the SASI, showing the instability's linear and nonlinear behaviors in a controlled setting.

Findings

Demonstrates a robust linear instability in the shallow water model

Shows symmetry breaking and nonlinear properties similar to astrophysical SASI

Validates the shallow water model as a tool for studying stellar core collapse phenomena

Abstract

Despite the sphericity of the collapsing stellar core, the birth conditions of neutron stars can be highly non spherical due to a hydrodynamical instability of the shocked accretion flow. Here we report the first laboratory experiment of a shallow water analogue, based on the physics of hydraulic jumps. Both the experiment and its shallow water modeling demonstrate a robust linear instability and nonlinear properties of symmetry breaking, in a system which is one million times smaller and about hundred times slower than its astrophysical analogue.