Coherent backscatter from ionospheric E-region plasma irregularities

1996 ◽  
Vol 58 (8-9) ◽  
pp. 933-941 ◽  
Author(s):  
K. Schlegel
1990 ◽  
Vol 52 (6-8) ◽  
pp. 431-438 ◽  
Author(s):  
I Häggström ◽  
H Opgenoorth ◽  
P.J.S Williams ◽  
G.O.L Jones ◽  
K Schlegel

2008 ◽  
Vol 26 (7) ◽  
pp. 1865-1876 ◽  
Author(s):  
D. V. Phanikumar ◽  
A. K. Patra ◽  
C. V. Devasia ◽  
G. Yellaiah

Abstract. In this paper, we present seasonal variation of E region field-aligned irregularities (FAIs) observed using the Gadanki radar and compare them with the seasonal variation of Es observed from a nearby location SHAR. During daytime, FAIs occur maximum in summer and throughout the day, as compared to other seasons. During nighttime, FAIs occur equally in both summer and winter, and relatively less in equinoxes. Seasonal variations of Es (i.e. ftEs and fbEs) show that the daytime activity is maximum in summer and the nighttime activity is maximum in equinoxes. No relation is found between FAIs occurrence/SNR and ftEs/fbEs. FAIs occurrence, however, is found to be related well with (ftEs−fbEs). This aspect is discussed in the light of the present understanding of the mid-latitude Es-FAIs relationship. The seasonal variations of FAIs observed at Gadanki are compared in detail with those of Piura, which show a significant difference in the daytime observations. The observed difference has been discussed considering the factors governing the generation of FAIs.


2011 ◽  
Vol 73 (17-18) ◽  
pp. 2444-2452 ◽  
Author(s):  
H.S.S. Sinha ◽  
R. Pandey ◽  
Shweta Sharma ◽  
R.N. Misra

2009 ◽  
Vol 27 (10) ◽  
pp. 3781-3790 ◽  
Author(s):  
A. K. Patra ◽  
D. V. Phanikumar

Abstract. Intriguing new results of F-region irregularities observed using the Gadanki MST radar during the SAFAR campaigns, which were conducted during the equinox and summer of 2008 that corresponds to low solar activity condition, are presented. The summer observations are first of its kind from Gadanki. Observations revealed remarkably different morphology of the F-region irregularities in summer when compared to that in equinox. In summer, the F-region irregularities were observed as horizontally stratified structures, while in equinox they were observed as plume structures. Further, the irregularities in summer commenced during the post-midnight hours in contrast to their commencement in the post-sunset hours and occurrence extending to post-midnight hours in equinox. In addition, an intriguing observation of the summer time irregularities is that they occurred when the background electron density was remarkably low as characterized by the disappearance of the F layer trace in the ionograms. An interesting event of equinox that was observed for 10 h and extended beyond the sunrise time displayed multiple plume structures having periods similar to those of the E-region velocity variations. These observations are discussed with due focus on the genesis of post-midnight F-region irregularities and their possible linkage to the E-region dynamics.


2012 ◽  
Vol 23 (3) ◽  
pp. 333
Author(s):  
Chi-Kuang Chao ◽  
Yen-Hsyang Chu ◽  
Ching-Lun Su ◽  
Shigeyuki Minami

1997 ◽  
Vol 15 (7) ◽  
pp. 870-877 ◽  
Author(s):  
K. Schlegel ◽  
A. V. Gurevich

Abstract. Recently, one of the authors (A. V. G.) developed a theory of low-frequency plasma irregularities which are created as a consequence of neutral turbulence in the D and lower E regions. In the following this theory will be applied to coherent backscatter experiments with radars in a frequency range between 5 and 150 MHz. We discuss the dependence of the backscatter cross-section on ionospheric as well as on turbulence parameters. The backscatter increases strongly with decreasing radar frequency. Above 15 MHz the effects discussed here can probably only be detected by very powerful radars with large antenna arrays.


2018 ◽  
Vol 56 (10) ◽  
pp. 5591-5599 ◽  
Author(s):  
Jenn-Shyong Chen ◽  
Chien-Ya Wang ◽  
Yen-Hsyang Chu ◽  
Ching-Lun Su ◽  
Hiroyuki Hashiguchi

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