Electrostatic Plasma Instabilities in the Equatorial Electrojet

Analyses of techniques for measuring DC and AC electric fields in the magnetosphere

“…Such measurements have been used to determine the power spectra of electrostatic plasma instabilities in the equatorial electrojet [152]. When combined with AC double probe electric field measurements they can produce information on the wavelength of the wave at a given frequency in the following way.…”

Equatorial electrojet 3-M irregularity dynamics during magnetic disturbances over Brazil: results from the new VHF radar at São Luı́s

“…Additionally, many important basic aspects of the electrojet irregularity processes have been discussed extensively in the literature (for example, Fejer and Kelley, 1980;St.-Maurice et al, 1986;Kudeki et al, 1985;Farley, 1985). Investigations by rocket borne diagnostics (Prakash et al, 1971;Pfa et al, 1987a,b) have contributed to continuing improvement in our understanding of the electrodynamical and plasma instability processes of the equatorial electrojet (Farley, 1963;Buneman, 1963). The magnetic equatorial region that has a large longitudinal extension (∼40 • ) in Brazil, possesses certain peculiarities in the geomagnetic ÿeld conÿguration distinctly di erent from other longitude sectors.…”

Spectral properties of electrostatic drift wave turbulence in the laboratory and the ionosphere

“…For an inertial (or coupling) subrange, the precise nature of the energy input should be of little consequence in the strong-turbulence limit, since the spectral shape would be expected to be controlled by the cascade, which will be the same for small-scale electrostatic drift and B-transverse velocity shear instabilities. The theoretical analysis of Tchen et al (1980) antici- (2000) 100-110 km 1 ± 0.25 3 ± 0.3 - Prakash et al (1971) 150 km --2.5 ± 0.5 LaBelle et al (1986) 300-500 km 2.5/4.5 -- Kelley et al (1982a) 390-560 km 2.2 ± 0.2/5.5 ± 0.5 -- Earle et al (1989) 450-500 km 2.2 ± 0.5 -2.9 ± 0.5 Kelley (1982); Kelley et al (1982b) 500 km 4.5 ± 0.4 -3.1 ± 0.3 pated this by having two different "production mechanisms" for the respective subranges of velocity and potential fluctuations. The hypothesis finds support in numerical simulations of nonlinear evolution of the Kelvin-Helmholtz instability in the high-latitude ionosphere (Keskinen et al, 1988), where the high-frequency short-wavelength part of the spectrum was found to have characteristics very similar to those of electrostatic drift waves.…”

“…The scatter in spectral indices is large, even within one experiment, and it is recommended that the original papers are consulted to see precisely what result they are being cited for. Note the correction of spectral indices (Prakash et al, 1971) that takes into account a varying filter bandwidth: this reference is predated by others (Prakash et al, 1968(Prakash et al, , 1969, containing an erroneous value for spectral indices. Values for positive spectral indices have been reported by Prakash et al (1971), but these apply only to some unspecified narrow spectral subranges and they are not included in the present summary.…”

“…Note the correction of spectral indices (Prakash et al, 1971) that takes into account a varying filter bandwidth: this reference is predated by others (Prakash et al, 1968(Prakash et al, , 1969, containing an erroneous value for spectral indices. Values for positive spectral indices have been reported by Prakash et al (1971), but these apply only to some unspecified narrow spectral subranges and they are not included in the present summary. Some rocket experiments (Pécseli et al, 1989Iranpour et al, 1997) report E region turbulent spectra in a colour-coded version, where a spectral index is not readily determined with any significant accuracy.…”