Transition regime of the one-dimensional two-stream instability

TL;DR

This paper analyzes the transition between kinetic and hydrodynamic regimes in the one-dimensional two-stream instability, providing numerical corrections to existing formulas and showing that previous estimates often overstate growth rates.

Contribution

It introduces numerical analysis of the transition regime and calculates correction coefficients to improve the accuracy of growth rate predictions.

Findings

Correction coefficients significantly improve growth rate estimates.

Approximate formulas overestimate growth rates in many parameter regions.

Numerical analysis clarifies the transition between regimes.

Abstract

The transition between kinetic and hydrodynamic regimes of the one-dimensional two-stream instability is numerically analyzed, and the correction coefficients to the well-known textbook formulae are calculated. The approximate expressions are shown to overestimate the growth rate several times in a wide parameter area.