Journal of Plasma Physics

Table of Contents - 2007 - Volume 73, Issue 01  

Papers

An assessment of how a combination of shears, field-aligned currents and collisions affect F-region ionospheric instabilities

J.-P. ST.-MAURICEa1, J.-M. NOËLa2 and P. J. PERRONa2

a1 Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E2 (jp.stmaurice@usask.ca)

a2 Department of Physics, Royal Military College of Canada, Kingston, Canada K7K 7B4

Abstract.

We present an in depth study of the fluid limit of a kinetically derived collisional, current-driven instability that includes shears in the field-aligned currents as well as collisions. We show how the theory presented here generalizes other theories, including the collisionless current-driven electrostatic ion acoustic instability and its sheared collisionless version. We offer a low-frequency generalization of the zero frequency ion shear driven instability by minimizing the relative drift magnitude as well as the shears themselves. We discuss the implication of our theoretical framework both for strongly field-aligned modes and modes where the wavevectors have arbitrary angles with respect to the ambient magnetic field. We discuss the results in terms of F-region irregularity observations of coherent echoes by ionospheric radars.

(Received October 31 2005)

(Accepted November 21 2005)