A study of the irregularities in the night time equatorial E-region using a Langmuir probe and plasma noise probe

Prakash, Satya; Gupta, S.P.; Subbaraya, B. H.

doi:10.1016/0032-0633(70)90141-8

Cited by 83 publications

(51 citation statements)

References 14 publications

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“…While the Type I irregularities are now identified to be consistent with the two-stream instability mechanism (Farley, 1963;Sato, 1972), the Type II irregularities are known to be produced by the nonlinear crossfield instability mechanism (Rogister & d'Angelo, 1970Balsley & Farley, 1973). Direct observations by Prakash et al (1970Prakash et al ( , 1971a using rocket-borne Langmuir probes flown from India, confirm the existence of the Type II irregularities in the equatorial E-region. Type II irregularities are characterized by scale sizes extending from a few meters up to tens of kilometres.…”

Section: Introductionmentioning

confidence: 84%

“…Their generation through the Rayleigh-Taylor (R-T) gravitational instability process and subsequent cascading, by secondary processes, into a hierarchy of irregularities was suggested by Haerendel (1974). The spectral characteristics of the different types of irregularities associated with the phenomenon of spread-F have been studied in detail (Prakash et al, 1970;Ott & Farley, 1974). The generation of small-scale plasma irregularities by the mechanism of cross-field instability (CFI) is also now reasonably well understood (Reid, 1968;Tsuda et al, 1969).…”

Section: Discussionmentioning

confidence: 99%

“…The short wavelength irregularities apparently seem to be generated from larger scale sizes by nonlinear coupling or cascading processes Rogister & d'Angelo, 1970Sato 1971Sato , 1973Sudan et al, 1973). Neutral turbulence also seems to be another probable mechanism responsible for the generation of plasma irregularities (Prakash et al, 1970). The spectral characteristics of the different types of irregularities have been studied in detail (Prakash et al, 1970;Ott & Farley, 1974).…”

Section: Introductionmentioning

confidence: 99%

“…Neutral turbulence also seems to be another probable mechanism responsible for the generation of plasma irregularities (Prakash et al, 1970). The spectral characteristics of the different types of irregularities have been studied in detail (Prakash et al, 1970;Ott & Farley, 1974).…”

Section: Introductionmentioning

confidence: 99%

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Spectral features of E- and F-region plasma irregularities as observed by rocket-borne electron density probes from Brazil

Muralikrishna¹,

Vieira²,

Abdu³

2007

Rev. Bras. Geof.

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ABSTRACT. The height variation of the ionospheric electron density was measured with rocket-borne electron density probes from Alcântara (2.31 • S; 35.2 • W) in Brazil. A Black Brant X sounding rocket was launched on 14-th October 1994 at 19h55min (LT) to investigate the phenomenon of high-altitude equatorial spread-F events. Ground equipments were operated during the campaign to ensure that the rocket was launched under conditions favorable for the generation of plasma bubbles in the F-region. The electron density was measured by three different types of probes. A High Frequency Capacitance probe (HFC) gave density data with low height resolution, while a conventional Langmuir Probe (LP) and a Plasma Frequency Probe (PFP) measured the electron density and the spatial fluctuations in it. The k-spectra of the plasma irregularities were obtained by the spectral analysis of the electron density fluctuation data. An important feature observed was the continuous presence of plasma irregularities of a large range of vertical scale sizes in the altitude range of 340 km to 817 km. The electron number density varied considerably in these spatial structures, for example a decrease by a factor of 2.6 in a vertical extension of 1 km near the altitude of 497 km. Near 535 km altitude the electron density increased by a factor of 1.8 within a height range of 2.7 km. Density structures of vertical scale sizes in the range of hundreds of meters also were observed superposed on the large-scale structures. During the rocket upleg two height regions of intense irregularities were observed, one between 366 and 480 km and the other between 684 and 812 km. The Langmuir Probe (LP) could make measurements of irregularities of vertical scale sizes more than 8 m in these height ranges, while the Plasma Frequency Probe, could make measurements of irregularities of vertical scale sizes as small as 0.5 m. Spectral features of these irregularities as observed by the two plasma probes at different height regions are presented and discussed here.Keywords: ionosphere, space plasma, plasma irregularities, rocket measurements, plasma density probes. RESUMO.A variação com altura da densidade eletrônica na ionosfera foi medida com sondas de densidade eletrônica a bordo de foguetes de Alcântara (2.31 • S; 35.2 • O) no Brasil. Um foguete de sondagem "Black Brant X" foi lançado no dia 14 de outubro de 1994às 19h55min (LT) para investigar o fenômeno de Espalhamento-F na alta ionosfera equatorial. Equipamentos foram operados na superfície terrestre durante a campanha para assegurar que o foguete foi lançado nas condições favoráveis pela geração das bolhas de plasma na região-F. A densidade eletrônica foi medida por três tipos diferentes de sondas. Uma sonda capacitiva em alta freqüência (HFC) forneceu os dados de densidade eletrônica de baixa resolução, quando uma sonda de Langmuir (LP) convencional e uma sonda de freqüência de plasma (PFP) mediram a densidade e as flutuações espaciais nela. Os espectros-k das irregularidades de plasma foram obtidas pela...

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Section: Introductionmentioning

confidence: 84%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Spectral features of E- and F-region plasma irregularities as observed by rocket-borne electron density probes from Brazil

Muralikrishna¹,

Vieira²,

Abdu³

2007

Rev. Bras. Geof.

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“…Earlier rocket¯ights from SHAR (Prakash et al, 1991) showed a number of large-scale structures in the region 100± 150 km with vertical scale sizes up to 25 km, but the electron density increase in such layers was only by a factor of 20 or less. The E-region¯ight from Thumba, reported by Prakash et al (1970), revealed the presence of layered structures with scale sizes of 5±10 km in 90± 130 km altitude region but the electron density increase in these structures was only by a factor of 10 or less. Based on the halfwidth of these layers (5±10 km), it appears that the internal gravity waves could be one plausible source for the generation of these sharp layers.…”

Section: Large-scale Irregularitiesmentioning

confidence: 96%

Some new features of electron density irregularities over SHAR during strong spread F

Raizada

Sinha

2000

Annales Geophysicae

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Abstract. An RH-560 rocket¯ight was conducted from Sriharikota rocket range (SHAR) (14°N, 80°E, dip latitude 5.5°N) to study electron density and electric ®eld irregularities during spread F. The rocket was launched at 2130 local time (LT) and it attained an apogee of 348 km. Results of electron density¯uctuations are presented here. Two extremely sharp layers of very high electron density were observed at 105 and 130 km. The electron density increase in these layers was by a factor of 50 in a vertical extent of 10 km. Large depletions in electron density were observed around 175 and 238 km. Both sharp layers as well as depletions were observed also during the descent. The presence of sharp layers and depletions during the ascent and the descent of the rocket as well as an order of magnitude less electron density, in 150±300 km region during the descent, indicate the presence of strong large-scale horizontal gradients in the electron density. Some of the valley region irregularities (165±178 km), in the intermediate scale size range, observed during this¯ight, show spectral peaks at 2 km and can be interpreted in terms of the image striation theory suggested by Vickrey et al. The irregularities at 176 km do not exhibit any peak at kilometer scales and appear to be of new type. The growth rate of intermediate scale size irregularities, produced through generalized Rayleigh Taylor instability, was calculated for the 200± 330 km altitude, using observed values of electron density gradients and an assumed vertically downward wind of 20 ms )1 . These growth rate calculations suggest that the observed irregularities could be produced by the gradient drift instability.

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Significance of Scatter Radar Studies of E and F Region Irregularities at High Latitudes

Greenwald

1983

High-Latitude Space Plasma Physics

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A study of the irregularities in the night time equatorial E-region using a Langmuir probe and plasma noise probe

Cited by 83 publications

References 14 publications

Spectral features of E- and F-region plasma irregularities as observed by rocket-borne electron density probes from Brazil

Spectral features of E- and F-region plasma irregularities as observed by rocket-borne electron density probes from Brazil

Some new features of electron density irregularities over SHAR during strong spread F

Significance of Scatter Radar Studies of E and F Region Irregularities at High Latitudes

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