An idealized problem with F2-layer applications

Abstract

An idealized problem is solved which illustrates the coupling between neutral air motion and the transport of plasma in a model F2-layer. The magnetic field lines are assumed to be horizontal and the effects of both vertically upwards and vertically downwards Hall drifts are considered. Very slow circulating motion of the neutral air is assumed to take place in a vertical plane parallel to the magnetic field lines. This motion is assumed to be coupled with the diffusive and Hall motions of the plasma. The problem first is studied in detail, and exactly, by assuming the electron density N to be a given function of position. The streamlines of the air motion are drawn and also a parameter b which is the ratio of the horizontal component of neutral air velocity to the horizontal velocity of the ions. The parameter b is found to lie within the range in which ion-drag might be expected to interfere seriously with the usual form of the F2-layer diffusion equation. It is shown secondly that if only the production and loss functions for electrons are known a non-linear diffusion equation is produced. It is suggested that in future theoretical. F2-layer calculations it may be necessary to construct a more complicated diffusion equation of this type, allowing for curvature of the field lines. The results indicate that for calculations of the magnitude of neutral air winds affected by ion-drag it may be a good approximation to assume that the horizontal ion velocity is the same as the horizontal neutral air velocity.