A statistical study of F‐region 3.2‐m‐scale field‐aligned irregularities (FAIs) occurrence and vertical plasma drift over Hainan: Solar activity, season and magnetic activity dependences

2021 ◽  
Author(s):  
Han Jin ◽  
Shasha Zou ◽  
Chunxiao Yan ◽  
Guotao Yang ◽  
Gang Chen ◽  
...  
Keyword(s):  
Solar Activity ◽  
Statistical Study ◽  
Magnetic Activity ◽  
Plasma Drift ◽  
F Region ◽  
Scale Field ◽  
Activity Season ◽  
Field Aligned Irregularities

scholarly journals Predicted and observed characteristics of small-scale field-aligned irregularities generated in the F-region by low power HF heating

2002 ◽  
Vol 20 (5) ◽  
pp. 647-653 ◽  
Author(s):  
E. Kolesnikova ◽  
T. R. Robinson ◽  
J. A. Davies
Keyword(s):  
Low Power ◽  
Decay Rate ◽  
Parametric Instability ◽  
Small Scale ◽  
F Region ◽  
Scale Field ◽  
Thermal Parametric Instability ◽  
Hf Heating ◽  
Heated Volume ◽  
Field Aligned Irregularities

Abstract. Simultaneous HF scattering from the different regions of the heated volume is used to investigate characteristics of the small-scale field-aligned irregularities in the F-region. Time of growth, decay rate and saturation level for different pump powers are deduced from the observations and are compared with their behaviour predicted by the thermal parametric instability model. As a result, the estimates of the density and of the temperature modifications inside of the irregularities are obtained.Key words. Ionosphere (ionospheric irregularities)

Artificial Small-scale Field-aligned Irregularities in the High Latitude Ionospheric F-region

2018 ◽  
Author(s):  
Nataly Blagoveshchenskaya ◽  
Tatiana Borisova ◽  
Alexey Kalishin ◽  
Timothy Yeoman
Keyword(s):  
High Latitude ◽  
Small Scale ◽  
F Region ◽  
Scale Field ◽  
Field Aligned Irregularities

Solar cycle and seasonal variations in F-region vertical drifts over Kodaikanal, India

1995 ◽  
Vol 13 (6) ◽  
pp. 633-640 ◽  
Author(s):  
K. B. Ramesh ◽  
J. H. Sastri
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Seasonal Variations ◽  
Normal Incidence ◽  
Magnetic Activity ◽  
Solar Flux ◽  
Seasonal Trend ◽  
F Region ◽  
Phase Path ◽  
10.7 Cm Solar Flux

Abstract. Measurements of the changes in phase path of F-region reflections at normal incidence at Kodaikanal (77° 28'E, 10° 14'N, dip 3°N) from February 1991 to February 1993 are used to determine the variation of the equatorial evening F-region vertical drifts (V z) with season, solar and magnetic activity. It is found that on average, at Kodaikanal, the post-sunset peak in Vz(Vzp) is higher in equinox and local winter months than in local summer. The day-to-day variability in V zp is highest in summer and lowest in winter. This seasonal trend persists even on magnetically quiet days (Ap \\leq14). Vzp is found to increase with 10.7 cm solar flux in all three seasons but tends to saturate for large flux values (>230 units) during local summer and winter months. Magnetic activity [represented by Ap as well as the time-weighted accumulations of a p and ap (τ)] does not seem to have any statistically significant effect on Vzp , except during equinoctial months of moderate solar activity, when Vzp decreases as magnetic activity increases.

Artificial small-scale field-aligned irregularities in the high latitude F region of the ionosphere induced by an X-mode HF heater wave

2011 ◽  
Vol 38 (8) ◽  
pp. n/a-n/a ◽  
Author(s):  
N. F. Blagoveshchenskaya ◽  
T. D. Borisova ◽  
T. K. Yeoman ◽  
M. T. Rietveld ◽  
I. M. Ivanova ◽  
...  
Keyword(s):  
High Latitude ◽  
Small Scale ◽  
F Region ◽  
Scale Field ◽  
Field Aligned Irregularities

Characteristics of VHF scintillations in the equatorial anomaly crest region in India

1995 ◽  
Vol 13 (7) ◽  
pp. 730-739 ◽  
Author(s):  
K. N. Pathak ◽  
R. D. Jivrajani ◽  
H. P. Joshi ◽  
K. N. Iyer
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Magnetic Activity ◽  
Summer Season ◽  
Equatorial Anomaly ◽  
Equatorial Station ◽  
F Region ◽  
Ionospheric Scintillations

Abstract. The characteristics of ionospheric scintillations at Rajkot in the equatorial anomaly crest region in India are described for the years 1987–1991 by monitoring the 244-MHz transmission from the satellite FLEETSAT. This period covers the ascending phase of solar cycle 22. Scintillations occur predominantly in the pre-midnight period during equinoxes and winter seasons and in the post-midnight period during summer season. During equinoxes and winter, scintillation occurrence increases with solar activity, whilst in summer it is found to decrease with solar activity. Statistically, scintillation occurrence is suppressed by magnetic activity. The characteristics observed during winter and equinoxes are similar to those seen at the equatorial station, Trivandrum. This, coupled with the nature of the post-sunset equatorial F-region drift and h'F variations, supports the view that at the anomaly crest station, scintillations are of equatorial origin during equinox and winter, whilst in summer they may be of mid-latitude type. The variations in scintillation intensity (in dB) with season and solar activity are also reported.

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