scholarly journals Spread?F and the Perturbations of the Maximum Electron Density of the F Layer

1962 ◽  
Vol 15 (2) ◽  
pp. 242 ◽  
Author(s):  
DG Singleton
Keyword(s):  
Electron Density ◽  
Critical Frequency ◽  
Magnetic Activity ◽  
Time Of Day ◽  
Dominant Effect ◽  
Middle Latitudes ◽  
Profound Influence ◽  
Maximum Electron Density ◽  
Spread F ◽  
Range Of Values

An analysis has been made of spread-F data obtained from LG.Y. f-plots for several ionosonde stations grouped about longitude 75� W. to establish whether there is any connection between the severity of frequency-spreading (ilJ) and the time of day, season of the year, magnetic activity, height of the F layer, critical frequency of the F layer, and the latitude of the ionosonde station. The diurnal variations of the severity of frequency spreading are found to vary considerably with latitude and season and no clear pattern emerges. Magnetic activity affects the value of ilf but again in a complex way which varies with latitude. The magnitude of ilf seems to be greatest when the layer is high and descending at low and middle latitudes but not at high latitudes. At all latitudes the magnitude of ilf is greatest when the critical frequency is lowest. This is considered to be the dominant effect having a profound influence on the diurnal and seasonal distributions of ilf. These results are discussed in terms of the hypothesis that frequency spreading is due to the availability of a range of values of N IDJ1x. at the maximum of the F2 layer. This range of values is thought to correspond to a system of irregularities each involving an enhancement or a deficiency of electron density relative to the background ionization. The extra ionization involved in the irregularities is estimated to be of the order of 10' electrons/c.c. and is found to vary little with season, magnetic activity, and latitude.

Critical frequency and maximum electron density of F2 region over four stations in the North American sector

2011 ◽  
Vol 73 (4) ◽  
pp. 420-429 ◽  
Author(s):  
R.G. Ezquer ◽  
M.A. Cabrera ◽  
J.L. López ◽  
M.R. Albornoz ◽  
M. Mosert ◽  
...  
Keyword(s):  
Electron Density ◽  
North American ◽  
Critical Frequency ◽  
The North ◽  
Maximum Electron Density

The electron content of the ionosphere at middle latitudes in summer

1964 ◽  
Vol 279 (1379) ◽  
pp. 497-509 ◽  
Keyword(s):  
Electron Density ◽  
Faraday Rotation ◽  
Middle Latitude ◽  
Diurnal Variations ◽  
Slab Thickness ◽  
Electron Content ◽  
Middle Latitudes ◽  
Maximum Electron Density ◽  
Short Period ◽  
Made In

Measurements of the electron content of the ionosphere obtained from observations of the differential Faraday rotation of moon-reflected signals on two closely spaced frequencies are described. Accurate values of the electron content on many successive days near the summer solstices of 1960 and 1961 are presented, and compared and contrasted with similar measurements made in the winter of 1960 (Evans & Taylor 1961). The diurnal variations of electron content, short-period irregular fluctuations in electron content, equivalent slab thickness and top-to-bottom ratio are all found to differ from those observed in winter. The middle latitude seasonal anomaly is found to be less prominent in the electron content than in the maximum electron density .

scholarly journals Some theoretical of ionospheric storms at middle latitudes

1998 ◽  
Vol 41 (4) ◽  
Author(s):  
G. A. Mansilla ◽  
J. R. Manzano
Keyword(s):  
Numerical Method ◽  
Electron Density ◽  
Geomagnetic Storm ◽  
Continuity Equation ◽  
Geomagnetic Storms ◽  
Neutral Wind ◽  
Wind Effects ◽  
Middle Latitudes ◽  
Maximum Electron Density ◽  
Density Values

Neutral wind effects in the F2-region during geomagnetic storms are theoretically studied solving the continuity equation (with production and loss of electrons) by means of a numerical method. This study was made for storms with sudden commencement at different times of day and at different latitudes. The results show that the equatorward movements of neutral air produce either enhanced or depressed maximum electron density values which depend on the velocity of these winds when the perturbation occurs at diurnal hours. If the geomagnetic storm is present during the night, only enhanced values are observed.

Equatorial Spread-F and Magnetic Activity

Nature ◽  
1958 ◽  
Vol 181 (4625) ◽  
pp. 1724-1725 ◽  
Author(s):  
A. J. LYON ◽  
N. J. SKINNER ◽  
R. W. WRIGHT
Keyword(s):  
Magnetic Activity ◽  
Equatorial Spread F ◽  
Spread F

scholarly journals Ionosonde Observations of Spread F and Spread Es at Low and Middle Latitudes during the Recovery Phase of the 7–9 September 2017 Geomagnetic Storm

2021 ◽  
Vol 13 (5) ◽  
pp. 1010
Author(s):  
Lehui Wei ◽  
Chunhua Jiang ◽  
Yaogai Hu ◽  
Ercha Aa ◽  
Wengeng Huang ◽  
...  
Keyword(s):  
Geomagnetic Storm ◽  
Large Scale ◽  
Satellite System ◽  
Recovery Phase ◽  
Ionospheric Irregularities ◽  
Middle Latitudes ◽  
Multiple Observations ◽  
Swarm Satellites ◽  
Spread F ◽  
Global Navigation Satellite

This study presents observations of nighttime spread F/ionospheric irregularities and spread Es at low and middle latitudes in the South East Asia longitude of China sectors during the recovery phase of the 7–9 September 2017 geomagnetic storm. In this study, multiple observations, including a chain of three ionosondes located about the longitude of 100°E, Swarm satellites, and Global Navigation Satellite System (GNSS) ROTI maps, were used to study the development process and evolution characteristics of the nighttime spread F/ionospheric irregularities at low and middle latitudes. Interestingly, spread F and intense spread Es were simultaneously observed by three ionosondes during the recovery phase. Moreover, associated ionospheric irregularities could be observed by Swarm satellites and ground-based GNSS ionospheric TEC. Nighttime spread F and spread Es at low and middle latitudes might be due to multiple off-vertical reflection echoes from the large-scale tilts in the bottom ionosphere. In addition, we found that the periods of the disturbance ionosphere are ~1 h at ZHY station, ~1.5 h at LSH station and ~1 h at PUR station, respectively. It suggested that the large-scale tilts in the bottom ionosphere might be produced by LSTIDs (Large scale Traveling Ionospheric Disturbances), which might be induced by the high-latitude energy inputs during the recovery phase of this storm. Furthermore, the associated ionospheric irregularities observed by satellites and ground-based GNSS receivers might be caused by the local electric field induced by LSTIDs.

Strong equatorial plasma bubble associated with prominent TEC enhancement observed at mid-latitude ionosphere under the quiescent condition

2021 ◽  
Author(s):  
Fuqing Huang ◽  
Jiuhou Lei ◽  
Chao Xiong
Keyword(s):  
Electron Density ◽  
Electron Content ◽  
Radio Waves ◽  
Plasma Bubble ◽  
Total Electron ◽  
Middle Latitudes ◽  
Multiple Observations ◽  
Equatorial Plasma Bubbles ◽  
Low Latitudes

<p>Equatorial plasma bubbles (EPBs) are typically ionospheric irregularities that frequently occur at the low latitudes and equatorial regions, which can significantly affect the propagation of radio waves. In this study, we reported a unique strong EPB that happened at middle latitudes over the Asian sector during the quiescent period. The multiple observations including total electron content (TEC) from Beidou geostationary satellites and GPS, ionosondes, in-situ electron density from SWARM and meteor radar are used to explore the characteristic and mechanism of the observed EPB. The unique strong EPB was associated with great nighttime TEC/electron density enhancement at the middle latitudes, which moves toward eastward. The potential physical processes of the observed EPB are also discussed.</p>

scholarly journals Satellite traces, range spread-F occurrence, and gravity wave propagation at the southern anomaly crest

2010 ◽  
Vol 28 (5) ◽  
pp. 1133-1140 ◽  
Author(s):  
M. A. Cabrera ◽  
M. Pezzopane ◽  
E. Zuccheretti ◽  
R. G. Ezquer
Keyword(s):  
Wave Propagation ◽  
Gravity Wave ◽  
Electron Density ◽  
Equatorial Anomaly ◽  
Ionospheric Station ◽  
Spread F ◽  
Range Spread

Abstract. Range spread-F (RSF) and occurrence of "satellite" traces prior to RSF onset were studied at the southern peak of the ionospheric equatorial anomaly (EA). Ionograms recorded in September 2007 at the new ionospheric station of Tucumán, Argentina (26.9° S, 294.6° E, dip latitude 15.5° S), by the Advanced Ionospheric Sounder (AIS) developed at the Istituto Nazionale di Geofisica e Vulcanologia (INGV), were considered. Satellite traces (STs) are confirmed to be a necessary precursor to the appearance of an RSF trace on the ionograms. Moreover, an analysis of isoheight contours of electron density seems to suggest a relationship between RSF occurrence and gravity wave (GW) propagation.

scholarly journals Study of mid-latitude nighttime enhancement in F-region electron density using tomographic images over the UK

2003 ◽  
Vol 21 (12) ◽  
pp. 2323-2328 ◽  
Author(s):  
R. S. Dabas ◽  
L. Kersley
Keyword(s):  
Electron Density ◽  
Magnetic Activity ◽  
Electron Content ◽  
Equatorial Anomaly ◽  
Tomographic Images ◽  
F Region ◽  
Electron Density Gradient ◽  
Modeling And Forecasting ◽  
Ionospheric Electron Content ◽  
The Uk

Abstract. Nighttime enhancements in ionospheric electron content (IEC)/peak electron density (NmF2) have been studied by various workers in the equatorial anomaly and mid-latitude regions. Such studies give an idea about their enhancement over that location only. In the present study tomographic images over the UK, which give a latitudinal versus height distributions of ionospheric electron density in a much wider area, have been used to study the anomalous increases in nighttime F-region electron density at mid-latitudes. From the analysis of four seasonal representative months (November 1997, March, June and October 1998) data it was noted that the majority of the cases of nighttime enhancements were observed after local midnight, with a maximum between 03:00–04:00 LT in the month of November 1997. Enhancements were observed mostly between 45–50° N latitudes, and their positions are not affected by magnetic activity (Kp ) variations, whereas the separation between the mid-latitude trough and enhancement decreases with increases in magnetic activity. This finding shows that only the trough moves equatorward with the increase in magnetic activity. It is also noted that the electron density gradient from the trough to the enhancement increases with an increase in Kp. Results are discussed in terms of downward plasma transport from the protonosphere to the ionosphere and the nighttime neutral winds.Key words. Ionosphere (mid-latitude ionosphere; modeling and forecasting; instruments and techniques)

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