Measurement of Negative Ions in the Lower Ionosphere (D-Layer) in the Polar Region.

Amemiya, Hiroshi; Nakamura, Yoshiharu

doi:10.5636/jgg.48.391

Cited by 7 publications

(3 citation statements)

References 36 publications

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“…Naively, one might expect sluggishness to also decrease with latitude for similar reasons; however, panels (b-1 ∼4) show a positive correlation of  with latitude, but a strong correlation for  rio and  rio s . One possible explanation for this mixed latitude dependence is variability in α eff which is known to have a strong dependence on anionic chemistry at higher latitudes (Amemiya & Nakamura, 1996;Mitra, 1974). Further detailed analysis and modeling of sluggishness across latitudes and local time may provide further insights into the variability of D-region chemistry.…”

Section: Discussionmentioning

confidence: 99%

Ionospheric Sluggishness: A Characteristic Time‐Lag of the Ionospheric Response to Solar Flares

et al. 2021

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The term "sluggishness" was coined by E. V. Appleton in the 1950s to describe the time delay between peak irradiance at solar noon and the resulting peak in ionospheric electron density. Sluggishness can be understood as an inertial property of the ionosphere that manifests as a lag of the ionospheric response to a solar driver. As shown by Appleton, estimates of sluggishness can be used to study the chemistry of the lower ionosphere, of the D-region in particular. In this study, for the first time, we have examined ionospheric sluggishness in terms of the time delay between the peak irradiance during a solar flare and the resulting peak in ionospheric electron density using HF instruments. Estimates of the delay are obtained using HF observations from riometers and SuperDARN radars that are primarily sensitive to absorption in the D-region. Two new methods for measuring delay are introduced. Sluggishness is shown to be anti-correlated with peak solar X-ray flux and positively correlated with zenith angle and latitude. The choices of instrument, method, and reference solar waveband affect the sluggishness estimation. A simulation study was performed to estimate the effective recombination coefficient in the D-region. The coefficient was found to vary by orders of magnitude with peak flare intensity. We argue that the variation in effective recombination coefficient with peak flare intensity is highly sensitive to changes in the negative and positive ion chemistry of the D-region, which is sensitive to the incoming solar X-ray and EUV radiation. Plain Language Summary A systematic time delay between peak incoming solar radiation during a solar flare and peak electron density in the ionosphere is known as ionospheric sluggishness. Ionospheric sluggishness is known to be maximized around D-region heights (∼60-90 km altitude). This article is our first attempt to estimate ionospheric sluggishness using high frequency (3-30 MHz) instruments. In addition, we statistically characterize the observed sluggishness and provide an insight into D-region photochemical processes. In this article, we also demonstrate how to extract the D-region's recombination coefficient using a theoretical model and measured sluggishness. CHAKRABORTY ET AL.

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Section: Discussionmentioning

confidence: 99%

Ionospheric Sluggishness: A Characteristic Time‐Lag of the Ionospheric Response to Solar Flares

et al. 2021

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“…Ionization of NO by the Lyα did not work at 80 km because of severe attenuation under the grazing incidence geometry. The negative to positive ion density ratios measured by the Faraday cup have already been discussed in a separate paper (Amemiya and Nakamura, 1996) for the S310.22 experiment, and those of S310.23 will be discussed in another paper.…”

Section: Electron and Ionsmentioning

confidence: 90%

“…It measured negative/positive ion currents by applying positive/negative biases on the probe alternately (Amemiya and Nakamura, 1996).…”

Section: Instrumentationmentioning

confidence: 99%

Polar thermosphere-stratosphere photochemical coupling experiment: Two rocket measurements in polar winter at 69°N

et al. 2014

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Two rocket experiments were carried out just before and after the polar night at Andoya (69°N), Norway to investigate transport of nitric oxide produced by auroral processes into the middle atmosphere and its influence on the ozone chemistry. Nitric oxide densities of (2-5) × 10 8 cm -3 found in the 70-90 km region are one to two orders of magnitude larger than those at middle latitudes. The measured density profiles appear to agree semiquantitatively with model simulations which includes auroral processes. The influence on ozone densities in the 70-90 km region due to such enhanced nitric oxide abundance is found to be still insignificant as compared to that due to transport in the middle of February, one month after the end of polar night and one month before the spring equinox. The larger ozone densities found in February (in spite of longer sunlit duration) than in November in the 40-60 km region again support predominance of transport over photochemical destruction.

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Study of dust Ion acoustic solitary wave with non-maxwellian electron-positron in magnetized plasmas

Dev¹,

Boro²,

Adhikary³

2023

AIP Conference Proceedings

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Measurement of Negative Ions in the Lower Ionosphere (D-Layer) in the Polar Region.

Cited by 7 publications

References 36 publications

Ionospheric Sluggishness: A Characteristic Time‐Lag of the Ionospheric Response to Solar Flares

Ionospheric Sluggishness: A Characteristic Time‐Lag of the Ionospheric Response to Solar Flares

Polar thermosphere-stratosphere photochemical coupling experiment: Two rocket measurements in polar winter at 69°N

Study of dust Ion acoustic solitary wave with non-maxwellian electron-positron in magnetized plasmas

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