Precession of a Strong Astron E Layer

Precession of weak E layers observed in the astron is compatible with the “superparticle” model according to which the electrons of the layer move as a rigid body at the precession rate of a single electron in the external magnetic fields. The superparticle assumption is investigated by perturbation of a Vlasov equilibrium E layer of arbitrary strength. A slow precessional motion of the layer is found with a frequency equal to the single electron external field precession rate in the weak E-layer limit. For strong E layers with loading factors ζ∼1, the precession frequency is reduced from the external field rate, due to the self-field of the layer, by an appreciable factor of the order of 1 + (R/2a)ζ, where R is the radius and a is the thickness of the layer. It is shown that there may be damping of the E-layer motion arising from the distribution in energy and/or momentum of the electrons.