Field-aligned<i>E</i>-region irregularities identified with acoustic plasma waves

Bowles, Kenneth L.; Balsley, B. B.; Cohen, Robert

doi:10.1029/jz068i009p02485

Cited by 177 publications

(87 citation statements)

References 28 publications

(19 reference statements)

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“…In the paper of Bowles, Balsley, and Cohen [1963], two important characteristics of the equatorial fieldalined reflection were used to demonstrate that the plasma acoustic wave mechanism appeared to be a valid explanation of the echoes. These two characteristics are reviewed here.…”

Section: Presentation Of Resultsmentioning

confidence: 99%

“…An example of the spectral data obtained by Bowles, Balsley, and Cohen [1963] is shown in figure 1. Examination of this illustration indicates that the Doppler shift (the peak in the spectra) occurs at essentially the same frequency for antenna beam elevation angles of 60 deg west and 30 deg west.…”

Section: Presentation Of Resultsmentioning

confidence: 99%

“…These waves have wave fronts alined with the magnetic fi eld lines of the earth and are expected to travel at the acoustic velocity of the medium. Bowles, Balsley, and Cohen [1963] and Cohen and Bowles [1963] have applied thi s co nce pt to explain the existence of fi el?-alined E-region irregularities seen at the magnetIC equator by Egan [1960] and others. Based u~on this inte rpretation, they demonstrate that the expenmental data appear to support the fact that the irregularities are most likely plane plasma acoustic waves that are generate d by an instability resulting from the flow of c urre nt in the equatorial electrojet.…”

Section: Introductionmentioning

confidence: 99%

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A comparison of radar auroral reflection data with acoustic wave theory

Leadabrand¹

1965

J. RES. NATL. BUR. STAN. SECT. D. RAD. SCI.

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A comparison is made be tween 400 and 800 MHz rada r auroral reflection data and th e co nce pt that the irregularities in electron de nsity responsible for the a uroral echoes are plas ma waves ge ? erated by in stabilities in the ionospheric current syste m. Th e waves so ge nera te? would have their ~av e front s paraUel to the earth's magneti c fi eld lin es and wou ld tra vel at th e aco ustI c velOCIty of th e me dIUm. The comparison indicates that, although many of th e key featu.res of the plas ma acoustic Wave co ncept can be found in the radar auroral data, the spect ral c ha rac te n sllcs of the a uroral ec hoes are muc h too complicated to be simply und erstood in th eir present form.

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Section: Presentation Of Resultsmentioning

confidence: 99%

Section: Presentation Of Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A comparison of radar auroral reflection data with acoustic wave theory

Leadabrand¹

1965

J. RES. NATL. BUR. STAN. SECT. D. RAD. SCI.

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“…Only recently has a theory su ccessfully explained cer tain equatorial sporadic-E irregularities co nnected with the elcctrojet current [Farley, 1963;M aeda et al, 1963] and perhaps also E-region irregularities in the auror~l zone. The theory seems to be confirmed expeI'lmentally [Bowles et al , 1963]. However , irregulari ties in the F-region in temper ate latitudes are also observed regularly and a theory to explain them has yet to be developed.…”

Section: Introductionmentioning

confidence: 67%

F-region irregularities studied by scintillation of signals from satellites

Yeh¹,

Swenson²

1964

J. RES. NATL. BUR. STAN. SECT. D. RAD. SCI.

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Scintillation of radio signals from earth satellites has b een studied for fiv e years during the d ecli ning phase of the sunspot cycle. It is found that the character of the scintillation, and thus, pr obably, of the ionospheric irregularities that cause them, var y systematically with geo magnetic latitud e, season of t he year, time of day, and phase of the s unspot cycle. Night time scintillation occurs in the F-l'eg ion, mainly at heights of about 350 km. This type of scintillation in most cases res ults from firs t-order scattering from weak, fi eld-alin ed irregularities in electron d ensity. In the Northern H em isphere such scintillations are observed north of a certain parallel of geo magnet ic latitud e, the so uthern limit varying weakly with magnetic activity. Simi lar effects arc a lso observed in the Sout h ern H emisphere. Daytim e sc intillations also sholV stro ng seasonal and s un spot-cycle depe nd ence but very little latit ud e d ep end ence.The scintillation observations of the present investigation have been compared with observation s of other manifestations of ionospheric irregularities, p articularly spread-F and radio "star" sci ntillation. It has been observed that s trong scintillation occurs simultan eously ,,-ith the occurrence of red auroral ar cs. Scintillat ion , b eing more common than red arcs, may be a more sensitive indicator of ionospher ic disturban ces.

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“…Sporadic-E, spread-F, radio star scintillations and VHF radar echoes are a few of such phenomena, familiar to ionospheric physicists. Basic knowledge of the plasma irregularities, responsible for these phenomena, has progressed considerably, both in theory and observations, since the discovery of the strong VHF radar echoes from the equatorial ionosphere (Bowles et al, 1960(Bowles et al, , 1963. Balsley (1969), from their spectral characteristics as observed by the VHF radar, classified the plasma irregularities into two groups, namely Type I and Type II.…”

Section: Introductionmentioning

confidence: 99%

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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Field-alignedE-region irregularities identified with acoustic plasma waves

Cited by 177 publications

References 28 publications

A comparison of radar auroral reflection data with acoustic wave theory

A comparison of radar auroral reflection data with acoustic wave theory

F-region irregularities studied by scintillation of signals from satellites

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

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