Mechanisms for E-F coupling and their manifestation

E-F coupling refers to the mapping of a polarization electric field away from its source in one region of the ionosphere (e.g., E region), and causing an effect in a remote region (e.g., F region). The source may be neutral dynamic in origin, or it may be electrodynamic, in which case feedback between remote regions may be important. This work outlines the main physical mechanisms and constraints thought to be involved in midlatitude E-F coupling, and discusses some of the challenges to inventing an illuminating observational campaign. Mechanisms for polarizing sporadic E layers, effectiveness of F region polarization, scale sizes for neutral dynamics in the E and F regions, mechanisms for modulating the F layer altitude, and typical conductance ratios for the E-F coupled electric circuit will all be discussed. Data from a recent rocket/radar study will be used to illustrate the results. (C) 2013 Elsevier Ltd. All rights reserved.