Effect of short-scale turbulence on kilometer wavelength irregularities in the equatorial electrojet

Journal Article · Mon Jan 01 04:00:00 EST 1990 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JA095iA01p00189· OSTI ID:5221414

Ronchi, C; Sudan, R N ^[1]; Similon, P L ^[2]

---

1. Cornell Univ., Ithaca, NY (United States)
2. Yale Univ., New Haven, CT (United States)

The kilometer scale irregularities in the daytime equatorial electrojet are studied within the framework of a two-fluid, nonlocal theory of the gradient drift instability. A separation of scales is introduced into the equations in order to model the effects of the subgrid, short-wavelength ({lambda} < 100 m) modes. The presence of the short-scale turbulence is included in the large-scale equations through the average nonlinear flux due to the small-scale nonlinear terms. With the use of the linear ion continuity equation the nonlinear flux is expressed in terms of the large-scale quantities and of the small-scale density fluctuation spectrum. It is shown that the small-scale turbulence contributes to the large-scale equations through turbulent mobility and diffusion coefficients. For a particular choice for the small-scale density fluctuation spectrum the turbulent mobility is determined as a function of altitude, and its peak equals a few times the classical Pedersen mobility value. The equilibrium solutions of the large-scale equations are also derived in the presence of the short-wavelength turbulence. The localization of the current layer is seen to shift toward higher altitudes, and the current density profile conforms well with some of the available experimental data.

• OSTI ID: 5221414
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 95:A1; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
&amp; Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CURRENT DENSITY
CURRENTS
DRIFT INSTABILITY
ELECTRIC CURRENTS
ELECTRIC FIELDS
ELECTRIC POTENTIAL
ELECTROJETS
ELECTRON DENSITY
EQUATOR
INSTABILITY
NONLINEAR PROBLEMS
PLASMA INSTABILITY
PLASMA MICROINSTABILITIES
PLASMA WAVES
TURBULENCE