scholarly journals Height comparison of midlatitude E region field-aligned irregularities and sporadic E Layer

1998 ◽  
Vol 25 (11) ◽  
pp. 1813-1816 ◽  
Author(s):  
Tadahiko Ogawa ◽  
Norihide Sekito ◽  
Kenrou Nozaki ◽  
Mamoru Yamamoto
Keyword(s):  
E Region ◽  
Sporadic E Layer ◽  
Sporadic E ◽  
Field Aligned Irregularities

scholarly journals Equatorial E Region Electric Fields and Sporadic E Layer Responses to the Recovery Phase of the November 2004 Geomagnetic Storm

2017 ◽  
Vol 122 (12) ◽  
pp. 12,517-12,533 ◽  
Author(s):  
J. Moro ◽  
L. C. A. Resende ◽  
C. M. Denardini ◽  
J. Xu ◽  
I. S. Batista ◽  
...  
Keyword(s):  
Geomagnetic Storm ◽  
Electric Fields ◽  
Recovery Phase ◽  
E Region ◽  
Sporadic E Layer ◽  
Sporadic E

scholarly journals Energetics and structure of the lower E region associated with sporadic E layer

2008 ◽  
Vol 26 (9) ◽  
pp. 2929-2936 ◽  
Author(s):  
K.-I. Oyama ◽  
K. Hibino ◽  
T. Abe ◽  
R. Pfaff ◽  
T. Yokoyama ◽  
...  
Keyword(s):  
Electric Field ◽  
Field Data ◽  
Magnetic Line ◽  
Height Range ◽  
Sounding Rockets ◽  
Main Structure ◽  
Irregular Structures ◽  
E Region ◽  
Sporadic E Layer ◽  
Sporadic E

Abstract. The electron temperature (Te), electron density (Ne), and two components of the electric field were measured from the height of 90 km to 150 km by one of the sounding rockets launched during the SEEK-2 campaign. The rocket went through sporadic E layer (Es) at the height of 102 km–109 km during ascent and 99 km–108 km during decent, respectively. The energy density of thermal electrons calculated from Ne and Te shows the broad maximum in the height range of 100–110 km, and it decreases towards the lower and higher altitudes, which implies that a heat source exists in the height region of 100 km–110 km. A 3-D picture of Es, that was drawn by using Te, Ne, and the electric field data, corresponded to the computer simulation; the main structure of Es is projected to a higher altitude along the magnetic line of force, thus producing irregular structures of Te, Ne and electric field in higher altitude.

scholarly journals Sporadic-E associated with the Leonid meteor shower event of November 1998 over low and equatorial latitudes

2001 ◽  
Vol 19 (1) ◽  
pp. 59-69 ◽  
Author(s):  
H. Chandra ◽  
S. Sharma ◽  
C. V. Devasia ◽  
K. S. V. Subbarao ◽  
R. Sridharan ◽  
...  
Keyword(s):  
Meteor Shower ◽  
Low Latitude ◽  
Equatorial Station ◽  
Radio Science ◽  
Ionospheric Physics ◽  
Transmitter Power ◽  
Multiple Structures ◽  
E Region ◽  
Sporadic E Layer ◽  
Sporadic E

Abstract. Rapid radio soundings were made over Ahmedabad, a low latitude station during the period 16–20 November 1998 to study the sporadic-E layer associated with the Leonid shower activity using the KEL Aerospace digital ionosonde. Hourly ionograms for the period 11 November to 24 November were also examined during the years from 1994 to 1998. A distinct increase in sporadic-E layer occurrence is noticed on 17, 18 and 19 November from 1996 to 1998. The diurnal variations  of  f0Es and fbEs also show significantly enhanced values for the morning hours of 18 and 19 November 1998. The ionograms clearly show strong sporadic-E reflections at times of peak shower activity with multiple traces in the altitude range of 100–140 km in few ionograms. Sporadic-E layers with multiple structures in altitude are also seen in some of the ionograms (quarter hourly) at Thumba, situated near the magnetic equator. Few of ionograms recorded at Kodaikanal, another equatorial station, also show sporadic- E reflections in spite of the transmitter power being significantly lower. These new results highlighting the effect of intense meteor showers in the equatorial and low latitude E-region are presented.Key words. Ionosphere (equatorial ionosphere) – Radio science (ionospheric physics)

scholarly journals Mid Latitude Sporadic E-layer Variability during Ascending Phase of Solar Cycle 24

2017 ◽  
Vol 9 (1) ◽  
pp. 27-41
Author(s):  
R. Atulkar ◽  
P. A. Khan ◽  
A. A. Mansoori ◽  
P. K. Purohit
Keyword(s):  
Solar Cycle ◽  
Summer Season ◽  
High Solar Activity ◽  
Night Time ◽  
Solar Cycle 24 ◽  
E Region ◽  
Sporadic E Layer ◽  
Sporadic E ◽  
Cycle 24 ◽  
Short Time

The paper presents a comparative study of the ionospheric sporadic E layer parameters (fbEs, foEs, and h’Es) retrieved from ground based ionosonde at mid latitude station Yamagawa, Japan (31.20 N, 130.370 E) during the ascending phase of 24th solar cycle i.e. during January 2012 to December 2014. The comparison between the E-region parameters has been carried out on a diurnal, seasonal, annual and day night basis. The diurnal maxima of foEs, fbEs, and h’Es are generally higher during high solar activity. From the present study it is found that the highest values of fbEs are observed during the summer while the lowest values are observed during autumn at mid latitude. Similarly, the highest values of foEs are observed during the summer season while the lowest values are recorded in autumn season. However, the highest values of h’Es are recorded during the spring and the lowest values are recorded in autumn. The variability of Es during the day and night time is also studied. The sporadic E can form and disappear in a short time during either the day or night. We have also studied the percentage occurrence of sporadic E. The occurrence of Es changes from year to year.

A discussion on D and E region winds over Europe - Some studies of sporadic E-layer drifts

1972 ◽  
Vol 271 (1217) ◽  
pp. 613-622 ◽  
Keyword(s):  
Large Scale ◽  
Great Majority ◽  
Theoretical Work ◽  
Night Time ◽  
Drift Motion ◽  
The Past ◽  
E Region ◽  
Sporadic E Layer ◽  
Sporadic E ◽  
Ionospheric Drifts

In the past two decades, measurements of E-region drifts, using the conventional closely spaced receiver method with pulse signals incident normally on the ionosphere, have been made by many workers. The great majority of such measurements have been carried out at frequencies in the 2 to 3 MHz range and refer to drift movements in the lower part of the normal E region. Measurements of sporadic E drifts by the fading method have almost always been limited to night-time hours, when the normal E layer is absent, and the results have generally been used to extend daytime normal E measurements over the full 24 h. The objectives of the present work, in which the fading method has again been used, were to obtain some simultaneous measurements of drift in the normal E and the sporadic E regions, to obtain some qualitative data on height gradient of sporadic E-layer drifts, and to compare the horizontal drifts of small- and large-scale sporadic E irregularities. (A survey of current experimental and theoretical work on sporadic E, and of outstanding problems, has recently been published by Whitehead (1970).) The closely spaced receiver technique measures changes in a diffraction pattern at the ground and the interpretation of these changes in terms of ‘ionospheric drift motion’ is, of course, open to question. Certain basic ambiguities in the interpretation of experimental data obtained in the fading method cannot readily be resolved and are likely to remain until some direct comparisons can be made with actual movements at ionospheric levels of both the ionized and neutral constituents. In continuing the practice of referring to the processed data as ‘ionospheric drifts’ we recognize that the more appropriate term would be ‘apparent ionospheric drifts’, and that the ‘drifts’ refer only to possible motion of, or within the ionization.

scholarly journals Artificial E-region field-aligned plasma irregularities generated at pump frequencies near the second electron gyroharmonic

2009 ◽  
Vol 27 (7) ◽  
pp. 2711-2720 ◽  
Author(s):  
D. L. Hysell ◽  
E. Nossa
Keyword(s):  
Plasma Density ◽  
Hybrid Wave ◽  
Pump Frequency ◽  
Coherent Scatter ◽  
Wave Trapping ◽  
Plasma Irregularities ◽  
Ionospheric Modification ◽  
E Region ◽  
Sporadic E Layer ◽  
Sporadic E

Abstract. E region ionospheric modification experiments have been performed at HAARP using pump frequencies about 50 kHz above and below the second electron gyroharmonic frequency. Artificial E region field-aligned plasma density irregularities (FAIs) were created and observed using the imaging coherent scatter radar near Homer, Alaska. Echoes from FAIs generated with pump frequencies above and below 2Ωe did not appear to differ significantly in experiments conducted on summer afternoons in 2008, and the resonance instability seemed to be at work in either case. We argue that upper hybrid wave trapping and resonance instability at pump frequencies below the second electron gyroharmonic frequency are permitted theoretically when the effects of finite parallel wavenumbers are considered. Echoes from a sporadic E layer were observed to be somewhat weaker when the pump frequency was 50 kHz below the second electron gyroharmonic frequency. This may indicate that finite parallel wavenumbers are inconsistent with wave trapping in thin sporadic E ionization layers.

scholarly journals A Case Study of Polar Cap Sporadic-E Layer Associated with TEC Variations

2021 ◽  
Vol 13 (7) ◽  
pp. 1324
Author(s):  
Yong Wang ◽  
Periyadan T. Jayachandran ◽  
David R. Themens ◽  
Anthony M. McCaffrey ◽  
Qing-He Zhang ◽  
...  
Keyword(s):  
Electron Content ◽  
High Electron ◽  
Gps Receiver ◽  
Polar Cap ◽  
Total Electron ◽  
Multiple Measurements ◽  
E Region ◽  
Sporadic E Layer ◽  
Sporadic E

The Sporadic-E (Es) layer is an often-observed phenomenon at high latitudes; however, our understanding of the polar cap Es layer is severely limited due to the scarce number of measurements. Here, the first comprehensive study of the polar cap Es layer associated with Global Positioning System (GPS) Total Electron Content (TEC) variations and scintillations is presented with multiple measurements at Resolute, Canada (Canadian Advanced Digital Ionosonde (CADI), Northward-looking face of Resolute Incoherent-Scatter Radar (RISR-N), and GPS receiver). According to the joint observations, the polar cap Es layer is a thin patch structure with variously high electron density, which gradually develops into the lower E region (~100 km) and horizontally extends >200 km. Moreover, the TEC variations produced by the polar cap Es layer are pulse-like enhancements with a general amplitude of ~0.5 TECu and are followed by smaller but rapid TEC perturbations. Furthermore, the possible scintillation effects likely associated with the polar cap Es layer are also discussed. As a consequence, the results widely expand our understanding on the polar cap Es layer, in particular on TEC variations.

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