Low latitude E-region irregularities studied using Gadanki radar, ionosonde and in situ measured electron density

• Published in: Astrophysics and space science Vol. 323; no. 3; pp. 225 - 233
• Main Authors: Phani Kumar, D. V., Patra, A. K., Kwak, Y.-S., Kim, K.-H., Yellaiah, G.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.10.2009; Springer Nature B.V
• Subjects: Astrobiology; Astronomy; Astrophysics; Astrophysics and Astroparticles; Cosmology; Density; Electric fields; Electrons; Observations and Techniques; Original Article; Physics; Physics and Astronomy; Radar; Radar systems; Space Exploration and Astronautics; Space Sciences (including Extraterrestrial Physics; India, Andhra Pradesh, Gadanki; Equatorial ionosphere; Plasma waves and instabilities; Ionospheric irregularities
• ISSN: 0004-640X; 1572-946X
• DOI: 10.1007/s10509-009-0066-y

In this paper, we attempt to identify the driving forces responsible for the generation of low-latitude E-region field-aligned irregularities (FAIs). It is evident that the low-latitude E-region FAIs occur both during the day and night with preferential occurrence being most during local sunrise period. Simultaneous measurements are made with Gadanki radar and nearby located Ionosonde for understanding the low-latitude Es–FAIs relationship. The observations suggest that the occurrence and SNR of FAIs have a close relationship with f t E s −− f b E s . Finally, using the past electron density profiles and reasonable values of electric field, we have shown that it is generally difficult with the gradient drift instability to explain low-latitude E-region FAIs when electric field alone is considered as driving agency. We hypothesize that neutral winds play important role for the generation of irregularities at low latitudes outside the electrojet belt either by forming sharp Es layers or by enhancing the differential drift of electrons and ions or by both.