Night-time light ion transition height behaviour over the Kharkiv (50°N, 36°E) IS radar during the equinoxes of 2006–2010

Kotov, Dmytro; Truhlík, Vladimír; Richards, P. G.; Stankov, S. M.; Bogomaz, Oleksandr; Черногор, Л. Ф.; Domnin, I. F.

doi:10.1016/j.jastp.2015.06.004

Cited by 21 publications

(53 citation statements)

References 58 publications

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“…The need to double or triple the H density agrees with the previous equinox results of Kotov et al . [].…”

Section: Resultsmentioning

confidence: 99%

“…In 1996, pulse length was 795 µs and height resolution was 120 km. In these cases, biases in plasma parameters caused by the range smearing of measured ACFs are significantly smaller than the statistical errors; the overestimation of F 2 layer peak height does not exceed 5–10 km at night and 10–20 km during the day [ Kotov et al ., ].…”

Section: Datamentioning

confidence: 99%

“…The description of the particular inputs used in this study is presented in the paper of Kotov et al . [].…”

Section: Flip Modelmentioning

confidence: 99%

“…Kotov et al . [] found a significant enhancement of N m F 2 at Kharkiv during the equinoxes from 2006 to 2010. Simulations with the field line interhemispheric plasma (FLIP) physical model [ Richards , ; Richards et al ., ] reproduced the O + densities well but underestimated the H + densities by factors of 2 to 3.…”

Section: Introductionmentioning

confidence: 99%

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The importance of neutral hydrogen for the maintenance of the midlatitude winter nighttime ionosphere: Evidence from IS observations at Kharkiv, Ukraine, and field line interhemispheric plasma model simulations

et al. 2016

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This study investigates the causes of nighttime enhancements in ionospheric density that are observed in winter by the incoherent scatter radar at Kharkiv, Ukraine. Calculations with a comprehensive physical model reveal that large downward ion fluxes from the plasmasphere are the main cause of the enhancements. These large fluxes are enabled by large upward H+ fluxes into the plasmasphere from the conjugate summer hemisphere during the daytime. The nighttime downward H+ flux at Kharkiv is sensitive to the thermosphere model H density, which had to be increased by factors of 2 to 3 to obtain model‐data agreement for the topside H+ density. Other studies support the need for increasing the thermosphere model H density for all seasons at solar minimum. It was found that neutral winds are less effective than plasmaspheric fluxes for maintaining the nighttime ionosphere. This is partly because increased equatorward winds simultaneously oppose the downward H+ flux. The model calculations also reveal the need for a modest additional heat flow from the plasmasphere in the afternoon. This source could be the quiet time ring current.

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“…The need to double or triple the H density agrees with the previous equinox results of Kotov et al . [].…”

Section: Resultsmentioning

confidence: 99%

Section: Datamentioning

confidence: 99%

“…The description of the particular inputs used in this study is presented in the paper of Kotov et al . [].…”

Section: Flip Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The importance of neutral hydrogen for the maintenance of the midlatitude winter nighttime ionosphere: Evidence from IS observations at Kharkiv, Ukraine, and field line interhemispheric plasma model simulations

et al. 2016

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“…The impacts of the recent deep and prolonged solar minimum on the electron density, temperature, spread F, and total electron content, as well as the vertical and zonal plasma drifts, over the equatorial and low-latitude ionosphere have been studied using different types of observational data, such as digisondes (Liu Libo et al, 2011;Candido et al, 2011;Chuo et al, 2013;Solomon et al, 2013;Narayanan et al, 2014), satellites (Solomon et al, 2011;Huang et al, 2010Huang et al, , 2012Chuo et al, 2013;Fejer et al, 2013) and incoherent scatter radar (Aponte et al, 2013;Kotov et al, 2015;Santos et al, 2016a). During the period of June 2008 the mean monthly F10.7 radio index reached an extremely low value of ∼ 65.7 × 10 −22 W m −2 Hz −1 , which represented a solar extreme ultraviolet (EUV) irradiance that was lower than during previous solar cycles.…”

Section: Introductionmentioning

confidence: 99%

Unusual behavior of quiet-time zonal and vertical plasma drift velocities over Jicamarca during the recent extended solar minimum of 2008

et al. 2017

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Abstract. The influence of the recent deep and prolonged solar minimum on the daytime zonal and vertical plasma drift velocities during quiet time is investigated in this work. Analyzing the data obtained from incoherent scatter radar from Jicamarca (11.95 • S, 76.87 • W) we observe an anomalous behavior of the zonal plasma drift during June 2008 characterized by lower than usual daytime westward drift and its early afternoon reversal to eastward. As a case study the zonal drift observed on 24 June 2008 is modeled using a realistic low-latitude ionosphere simulated by the Sheffield University Plasmasphere-Ionosphere Model-INPE (SUPIM-INPE). The results show that an anomalously low zonal wind was mainly responsible for the observed anomalous behavior in the zonal drift. A comparative study of the vertical plasma drifts obtained from magnetometer data for some periods of maximum (2000)(2001)(2002) and minimum solar activity (1998, 2008, 2010) phases reveal a considerable decrease on the E-region conductivity and the dynamo electric field during 2008. However, we believe that the contribution of these characteristics to the unusual behavior of the zonal plasma drift is significantly smaller than that arising from the anomalously low zonal wind. The SUPIM-INPE result of the critical frequency of the F layer (foF2) over Jicamarca suggested a lower radiation flux than that predicted by solar irradiance model (SOLAR2000) for June 2008.

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Investigation of the causes of the longitudinal variation of the electron density in the Weddell Sea Anomaly

et al. 2017

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This paper investigates and quantifies the causes of the Weddell Sea Anomaly (WSA), a region near the tip of South America extending from approximately 30° to 120°W geographic longitude and 50° to 75°S geographic latitude at solar minimum between 2007 and 2010. This region is unusual because the midnight peak electron density exceeds the midday peak electron density in summer. This study is far more quantitative than previous studies because, unlike other models, it assimilates selected data parameters to constrain a physical model in order to investigate other aspects of the data. It is shown that the commonly accepted explanation that the WSA is related to the magnetic field declination and inclination effects on the neutral wind does not explain the longitudinal variation of the electron density. Rather, longitudinal changes in the neutral winds and neutral densities are the most likely explanation for the WSA. These longitudinal wind and density changes are attributed to the varying latitudinal distance from the auroral zone energy input. No contributions from the plasmasphere or other sources are required. Furthermore, it is shown that a widely used empirical thermosphere density model overestimates the longitudinal changes in the WSA region.

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Night-time light ion transition height behaviour over the Kharkiv (50°N, 36°E) IS radar during the equinoxes of 2006–2010

Cited by 21 publications

References 58 publications

The importance of neutral hydrogen for the maintenance of the midlatitude winter nighttime ionosphere: Evidence from IS observations at Kharkiv, Ukraine, and field line interhemispheric plasma model simulations

The importance of neutral hydrogen for the maintenance of the midlatitude winter nighttime ionosphere: Evidence from IS observations at Kharkiv, Ukraine, and field line interhemispheric plasma model simulations

Unusual behavior of quiet-time zonal and vertical plasma drift velocities over Jicamarca during the recent extended solar minimum of 2008

Investigation of the causes of the longitudinal variation of the electron density in the Weddell Sea Anomaly

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