Density fluctuations in the interstellar medium: Evidence for anisotropic magnetogasdynamic turbulence. II - Stationary structures

Abstract

A model of anisotropic plasma fluids is developed to examine the origin of the spectra of random, electron-density variations inferred by Armstrong, Cordes, and Rickett from measurements of pulsar radio signals. These electron variations are interpreted as density components of an anisotropic stationary mode of nonlinear magnetogasdynamics-tangetial pressure balances. It is demonstrated that turbulent flows, generated by the disruption of H I clouds in O star H II regions, reproduce well the mean electron spectrum inferred by Armstrong et al., if the relative rms density variation, &gt;(n-n<SUB>0</SUB>)<SUP>2</SUP>&lt;<SUP>1/2</SUP>/n<SUB>0</SUB> is 0.125, where n<SUB>0</SUB> is the mean density.