An Improved Type of Electron Temperature Probe

Hirao, Kazuyuki; Oyama, K. I.

doi:10.5636/jgg.22.393

Cited by 39 publications

(16 citation statements)

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“…Since the memory of the recorder on board the satellite was limited, only 4 to 6 orbits of data per day were transmitted to the data acquisition station at the Kagoshima Space Center. The electron density and electron temperature were measured by an impedance probe in an upper resonance mode (Watanabe and Oya, 1986) and a resonance recti®cation probe (Hirao and Oyama, 1970), respectively. The relative error of the electron density measurements is about 10% and the maximum error of the electron temperature is about 50 K. It should be pointed out that normally the F2 layer peak of the ionosphere is lower than the altitude of the satellite (600 km), although the peak might occasionally move to above 600 km around equator during the postsunset period (Su et al, 1997).…”

Section: Data Analysis and Resultsmentioning

confidence: 99%

Yearly variations in the low-latitude topside ionosphere

Bailey

Oyama

2000

Ann. Geophys.

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Abstract. Observations made by the Hinotori satellite have been analysed to determine the yearly variations of the electron density and electron temperature in the lowlatitude topside ionosphere. The observations reveal the existence of an equinoctial asymmetry in the topside electron density at low latitudes, i.e. the density is higher at one equinox than at the other. The asymmetry is hemisphere-dependent with the higher electron density occurring at the March equinox in the Northern Hemisphere and at the September equinox in the Southern Hemisphere. The asymmetry becomes stronger with increasing latitude in both hemispheres. The behaviour of the asymmetry has no signi®cant longitudinal and magnetic activity variations. A mechanism for the equinoctial asymmetry has been investigated using CTIP (coupled thermosphere ionosphere plasmasphere model). The model results reproduce the observed equinoctial asymmetry and suggest that the asymmetry is caused by the north-south imbalance of the thermosphere and ionosphere at the equinoxes due to the slow response of the thermosphere arising from the eects of the global thermospheric circulation. The observations also show that the relationship between the electron density and electron temperature is dierent for daytime and nighttime. During daytime the yearly variation of the electron temperature has negative correlation with the electron density, except at magnetic latitudes lower than 10°. At night, the correlation is positive.

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Section: Data Analysis and Resultsmentioning

confidence: 99%

Yearly variations in the low-latitude topside ionosphere

Bailey

Oyama

2000

Ann. Geophys.

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“…The electron temperature and density data used in the study were obtained from the observations made during 1981-82 by an electron temperature probe (Hirao and Oyama, 1970) and an impedance probe (Oya et al, 1986) on board the Hinotori satellite which was in a circular orbit at an altitude of -600 km. The inclination of the satellite was 31 degrees.…”

Section: Observationsmentioning

confidence: 99%

Morning Overshoot of Te Enhanced by Downward Plasma Drift in the Equatorial Topside Ionosphere.

Oyama

Balan

Watanabe

et al. 1996

J. geomagn. geoelec

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The morning overshoot in electron temperature, Te, which occurs in the sunlit atmosphere of low electron density during early morning hours, is a well known phenomenon. Studies of the phenomenon carried out using the Hinotori satellite observations reveal that the overshoot enhances in the topside equatorial F-region for a short period of time in the morning. The enhancement in the overshoot is found to depend on season and solar activity; it is strong during the northern summer months and grows with the increase in solar activity. Theoretical model calculations show that the enhancement in Te is caused by a reduction in electron density in the topside ionosphere due to a downward drift of plasma.

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“…Almost without exception the surface of the electrode is contaminated. However even we remove the effect of electrode contamination or use the instrument which can avoid the electrode contamination (Hirao and Oyama, 1970;Oyama and Hirao, 1976), T e measured by DC Langmuir probe is higher than model T n (Oyama et al, 1980;Duhau and Azpiazu, 1985;Amemiya et al, 1985), although very rarely we observed T e which is very close to T n (Hirao and Oyama, 1973;Rohde et al, 1993).…”

Section: Introductionmentioning

confidence: 92%

Possible interaction between thermal electrons and vibrationally excited N<sub>2</sub> in the lower E-region

et al. 2011

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Abstract. As one of the tasks to find the energy source(s) of thermal electrons, which elevate(s) electron temperature higher than neutral temperature in the lower ionosphere Eregion, energy distribution function of thermal electron was measured with a sounding rocket at the heights of 93-131 km by the applying second harmonic method.The energy distribution function showed a clear hump at the energy of ∼0.4 eV. In order to find the reason of the hump, we conducted laboratory experiment. We studied difference of the energy distribution functions of electrons in thermal energy range, which were measured with and without EUV radiation to plasma of N 2 /Ar and N 2 /O 2 gas mixture respectively. For N 2 /Ar gas mixture plasma, the hump is not clearly identified in the energy distribution of thermal electrons. On the other hand for N 2 /O 2 gas mixture, which contains vibrationally excited N 2 , a clear hump is found when irradiated by EUV.The laboratory experiment seems to suggest that the hump is produced as a result of interaction between vibrationally excited N 2 and thermal electrons, and this interaction is the most probable heating source for the electrons of thermal energy range in the lower E-region. It is also suggested that energy distribution of the electrons in high energy part may not be Maxwellian, and DC probe measures the electrons which are non Maxwellian, and therefore "electron temperature" is calculated higher.

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An Improved Type of Electron Temperature Probe

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Cited by 39 publications

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Yearly variations in the low-latitude topside ionosphere

Yearly variations in the low-latitude topside ionosphere

Morning Overshoot of Te Enhanced by Downward Plasma Drift in the Equatorial Topside Ionosphere.

Possible interaction between thermal electrons and vibrationally excited N<sub>2</sub> in the lower E-region

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An Improved Type of Electron Temperature Probe

Abstract: It has already been

Cited by 39 publications

References 0 publications

Yearly variations in the low-latitude topside ionosphere

Yearly variations in the low-latitude topside ionosphere

Morning Overshoot of Te Enhanced by Downward Plasma Drift in the Equatorial Topside Ionosphere.

Possible interaction between thermal electrons and vibrationally excited N&lt;sub&gt;2&lt;/sub&gt; in the lower E-region

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Possible interaction between thermal electrons and vibrationally excited N<sub>2</sub> in the lower E-region