Absence of streaming plasma waves around noontime over Thumba in recent times: Is it related to the movement of the dip equator?

Sekar, R.; Gupta, S.P.; Acharya, Y. B.; Chakrabarty, D.; Pallamraju, Duggirala; Pathan, B. M.; Tiwari, Diwakar; Choudhary, R. K.

doi:10.1016/j.jastp.2013.02.005

Cited by 6 publications

(2 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These rocket flight experiments were conducted during 1971–1975 when the dip angle over TERLS was between −1.1° to −1.0°. Therefore, the presence of two‐stream irregularities at the times of these rocket flights is consistent with the observation made by Sekar et al () that the two‐stream irregularities are generated over Thumba when the dip angle is less than 1.5°.…”

Section: Discussionsupporting

confidence: 92%

See 1 more Smart Citation

Altitude of Two‐Stream Irregularities in Equatorial E Region Using Sounding Rocket Experiments From Thumba

Pandey

Gupta

2020

JGR Space Physics

View full text Add to dashboard Cite

Amplitudes of two-stream irregularities and equatorial electrojet (EEJ) current are known to peak around the same altitude. Sounding rocket-borne magnetometer experiments have consistently shown that the EEJ current density maximizes around 105-km altitude whereas the theoretical models predict the EEJ peak around 100 km. One of the propositions to bridge this difference in the altitude has been based on the inclusion of small-scale turbulence (wavelength of <100 m) with the large-scale dynamics (kilometer size). This proposition is examined based on in situ measurements of E region electron density and plasma irregularities (two-stream and gradient-drift irregularities) obtained at different times of the day and night. These measurements were obtained based on sounding rocket flight experiments conducted from Thumba Equatorial Rocket Launching Station (8.54 • N, 76.86 • E), a facility in the vicinity of the dip equator. Whenever two-stream irregularities are present, the minimum electrojet current density is estimated based on the threshold velocity required for generation of these plasma irregularities. This method provides estimates of nighttime E region current also, which is difficult to measure. It is found that amplitudes of both two-stream irregularities and the estimated EEJ current peak around 105-km altitude irrespective of the presence or absence of the gradient-drift irregularities at the base of electrojet (95-to 100-km altitude).

show abstract

Section: Discussionsupporting

confidence: 92%

“…Here ν and Ω represent collision and gyrofrequencies with subscripts i and e representing ions and electrons, respectively. Around 105‐km altitude, the values of ψ and V i are about 0.1 and 330 m/s, respectively (Sekar et al, ). This corresponds to V d more than 360 m/s.…”

Section: Data Set and Methodologymentioning

confidence: 99%