Nighttime E region plasma irregularities over an equatorial station Trivandrum

2011 ◽  
Vol 73 (17-18) ◽  
pp. 2444-2452 ◽  
Author(s):  
H.S.S. Sinha ◽  
R. Pandey ◽  
Shweta Sharma ◽  
R.N. Misra
Keyword(s):  
Equatorial Station ◽  
Plasma Irregularities ◽  
E Region ◽  
Region Plasma

Application of alternating codes for EISCAT observations during the ERRRIS campaign for E-region plasma irregularities

1990 ◽  
Vol 52 (6-8) ◽  
pp. 431-438 ◽  
Author(s):  
I Häggström ◽  
H Opgenoorth ◽  
P.J.S Williams ◽  
G.O.L Jones ◽  
K Schlegel
Keyword(s):  
Plasma Irregularities ◽  
E Region ◽  
Region Plasma

scholarly journals Seasonal variation of low-latitude E-region plasma irregularities studied using Gadanki radar and ionosonde

2008 ◽  
Vol 26 (7) ◽  
pp. 1865-1876 ◽  
Author(s):  
D. V. Phanikumar ◽  
A. K. Patra ◽  
C. V. Devasia ◽  
G. Yellaiah
Keyword(s):  
Seasonal Variation ◽  
Seasonal Variations ◽  
Low Latitude ◽  
Plasma Irregularities ◽  
Daytime Activity ◽  
Significant Difference ◽  
E Region ◽  
Region Plasma ◽  
Present Understanding ◽  
Field Aligned Irregularities

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.

scholarly journals Intriguing aspects of F-region plasma irregularities revealed by the Gadanki radar observations during the SAFAR campaign

2009 ◽  
Vol 27 (10) ◽  
pp. 3781-3790 ◽  
Author(s):  
A. K. Patra ◽  
D. V. Phanikumar
Keyword(s):  
Solar Activity ◽  
Electron Density ◽  
Plasma Irregularities ◽  
F Region ◽  
Mst Radar ◽  
E Region ◽  
Summer Time ◽  
Interesting Event ◽  
Region Plasma ◽  
Activity Condition

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.

scholarly journals In-Situ Measurement of Ionospheric E-Region Plasma Irregularities over Taiwan

2012 ◽  
Vol 23 (3) ◽  
pp. 333
Author(s):  
Chi-Kuang Chao ◽  
Yen-Hsyang Chu ◽  
Ching-Lun Su ◽  
Shigeyuki Minami
Keyword(s):  
In Situ Measurement ◽  
Plasma Irregularities ◽  
E Region ◽  
Region Plasma

scholarly journals 3-D Radar Imaging of E-Region Field-Aligned Plasma Irregularities by Using Multireceiver and Multifrequency Techniques

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

scholarly journals Multi-technique investigations of storm-time ionospheric irregularities over the São Luís equatorial station in Brazil

2004 ◽  
Vol 22 (10) ◽  
pp. 3513-3522 ◽  
Author(s):  
E. R. de Paula ◽  
K. N. Iyer ◽  
D. L. Hysell ◽  
F. S. Rodrigues ◽  
E. A. Kherani ◽  
...  
Keyword(s):  
Electric Fields ◽  
Power Spectra ◽  
Spectral Width ◽  
Radar Data ◽  
Ionospheric Irregularities ◽  
Quiet Time ◽  
Vhf Radar ◽  
Equatorial Station ◽  
Plasma Irregularities ◽  
Magnetospheric Convection

Abstract. On 11 April 2001, a large magnetic storm occurred with SSC at 13:43 UT, and Dst reached below -200nT after two southward Bz excursions. The Kp index during this storm reached 8 and remained high (>4) for about 21h, and the São Luís magnetometer H component presented simultaneous oscillations and decreased substantially relative to the previous magnetically quiet days. This storm triggered strong ionospheric irregularities, as observed by a recently installed 30MHz coherent scatter radar, a digisonde, and a GPS scintillation receiver, all operating at the São Luís equatorial station (2.33° S, 44° W, dip latitude 1.3° S). The ionospheric conditions and the characteristics of the ionospheric irregularities observed by these instruments are presented and discussed. The VHF radar RTI (Range Time Intensity) echoes and their power spectra and spectral width for the storm night 11-12 April 2001, were used to analyse the nature and dynamics of the plasma irregularities and revealed the coexistence of many structures in the altitudinal range of 400-1200km, some locally generated and others that drifted from other longitudinal sectors. The radar data also revealed that the plumes had periodic eastward and westward zonal velocities after 22:20 UT, when well-developed quiet-time plumes typically drift eastward. Another interesting new observation is that the F-layer remained anomalously high throughout the 11-12 April 2001 storm night (21:00 UT to 09:00 UT next day) (the LT at São Luís is UT -3h), as indicated by the digisonde parameters hmF2 and h'F, which is a condition favourable for spread F generation and maintenance. The AE auroral index showed enhancements (followed by decreases) that are indicative of magnetospheric convection enhancements at about 15:00 UT, 20:00 UT and 22:00 UT on 11 April 2001 and at 00:20 UT (small amplitude) on 12 April 2001, associated with many Bz fluctuations, including clear two southward incursions that gave rise to large and long lasting Kp values and large negative Dst values. This intense auroral activity generated disturbance dynamo and prompt penetration electric fields that were responsible for the maintenance of the F-layer at a high altitude along the night of 11-12 April 2001. The short-lived F-region height rise seen between 16:00 to 18:00 UT on 11 April 2001 is probably due to the prompt penetration eastward electric fields of magnetospheric origin during the first IMF Bz turning to south around 15:00 UT.

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