Nonlinear ion-acoustic (IA) waves driven in a cylindrically symmetric flow

TL;DR

This paper investigates nonlinear ion-acoustic waves in cylindrical space plasma models, revealing new wave structures and behaviors, supported by numerical simulations and satellite data analysis.

Contribution

It introduces a self-similar two-fluid MHD model in cylindrical geometry to study nonlinear IA waves, uncovering novel wave features and behaviors not seen in Cartesian models.

Findings

Identification of three known nonlinear wave shapes: sinusoidal, sawtooth, and bipolar.

Discovery of new phenomena such as reversely propagating waves, density dips and humps.

Observation of electric shocks that diverge and converge.

Abstract

By employing a self-similar, two-fluid MHD model in a cylindrical geometry, we study the features of nonlinear ion-acoustic (IA) waves which propagate in the direction of external magnetic field lines in space plasmas. Numerical calculations not only expose the well-known three shapes of nonlinear structures (sinusoidal, sawtooth, and spiky or bipolar) which are observed by numerous satellites and simulated by models in a Cartesian geometry, but also illustrate new results, such as, two reversely propagating nonlinear waves, density dips and humps, diverging and converging electric shocks, etc. A case study on Cluster satellite data is also introduced.