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The 22 July 2009 Total Solar Eclipse: Modeling D Region Ionosphere Using Narrowband VLF Observations

Venkatesham, K.; Singh, Rajesh; Maurya, Ajeet K.; Dube, Adarsh; Kumar, Sushil; Phanikumar, D.V. (2019)

We present D region ionospheric response to 22 July 2009 total solar eclipse by modeling 19.8-kHz signal from NWC very low frequency (VLF) navigational transmitter located in the Australia. NWC VLF signal was received ...
The 25 April 2015 Nepal Earthquake: Investigation of precursor in VLF subionospheric signal

Maurya, A.K.; Venkatesham, K.; Tiwari, P.; Vijaykumar, K.; Singh, Rajesh; Singh, Ajay K.; Ramesh, D.S. (2016)

We present a critical analysis of the observations and interpretation of VLF subionospheric measurements related to the main Nepal Gorkha earthquake which occurred on 25 April 2015 (Mw7.8) and its major aftershock on 12 ...
630 nm nightglow observations from 17 degree N latitude

Mukherjee, G.K.; Carlo, L.; Mahajan, S.H. (2000)

Regular measurements of [OI] 630 nm nightglow have been carried out at Kolhapur (16.8◦N, 74.2◦E, dip lat 10.6◦N) in India with the help of tilting filter photometers during clear moonless nights. Several characteristic nightglow ...
Abnormal behaviour of sporadic E-layer during the total solar eclipse of 22 July 2009 near the crest of EIA over India

Tiwari, Prabhakar; Parihar, Navin; Dube, Adarsh; Singh, Rajesh; Sripathi, S. (2019)

In this study we present the behaviour of sporadic E-layer during a total solar eclipse (TSE) which occurred during the dawn/sunrise hours over a site located in the path of totality. A Canadian Advanced Digital Ionosonde ...
Absence of High Frequency Echoes From Ionosondes During the 23–25 April 2023 Geomagnetic Storm; What Happened?

Habarulema, John Bosco; Zhang, Yongliang; Matamba, Tshimangadzo; Buresova, Dalia; Lu, Gang; Katamzi‐Joseph, Zama; Fagundes, Paulo Roberto; Okoh, Daniel; Seemala, Gopi (2024-03)

We report an unusual event on absence of high frequency (HF) echoes in ionosonde observations from the ionospheric F2 region during the geomagnetic storm of 23–25 April 2023. This event was observed in both southern and ...
Active (Evolving) phase of equatorial plasma bubbles observed over Tirunelveli

Kakad, Bharati; Gurram, P.; Bhattacharyya, A.; Prasad, D. S. V. V. D (2020)

Usual post-sunset generation of equatorial spread F (ESF) irregularities on quiet days (Q-days) and midnight or post-midnight generation of ESF on magnetically disturbed days (D-days) is widely known. However, the duration ...
Advanced meteor radar installed at Tirupati: System details and comparison with different radars

Rao, S. Vijaya Bhaskara; Eswaraiah, S.; Ratnam, M. Venkat; Kosalendra, E.; Kumar, K. Kishore; Sathishkumar, S.; Patil, P.T.; Gurubaran, S. (2014)

An advanced meteor radar, viz, Sri Venkateswara University (SVU) meteor radar (SVU MR) operating at 35.25 MHz, was installed at Sri Venkateswara University (SVU), Tirupati (13.63°N, 79.4°E), India, in August 2013 for ...
An aided Abel inversion technique assisted by artificial neural network-based background ionospheric model for near real-time correction of FORMOSAT-7/COSMIC-2 data

Gowtam, V.Sai; Tulasiram, S.; Ankita, M. (2021)

The assumption of spherical uniformity while the retrieval of electron density profiles from the Global Navigation Satellite Systems-Radio Occultation (GNSS-RO) observations is often violated and introduces significant ...
Airglow and other F-layer variations in the Indian sector during the geomagnetic storm of February 5-7, 2000

Mukherjee, G.K. (2006)

A CCD based all-sky imaging system was used to monitor various nightglow emissions (OI 630-nm, OI 557.7-nm, OI 777.4-nm, Na (589.3-nm) and hydroxyl (OH) airglow) at a low latitude station, Kolhapur (16.8°N, 74.2°E, dip lat ...
Airglow imaging observations of small‐scale structures driven by convective instability in the upper mesosphere over Tirunelveli (8.7°N)

Narayanan, V. Lakshmi; Gurubaran, S.; Emperumal, K. (2010)

Airglow imaging observations of broadband OH Meinel band emissions made on the night of 20 January 2007 from the tropical Indian site Tirunelveli (8.7°N, 77.8°E) reveal large‐ and small‐scale wave features that are aligned ...
Airglow imaging observations of some evolutionary aspects of equatorial plasma bubbles from Indian sector

Gurav, O.B.; Narayanan, V.L.; Sharma, A.K.; Ghodpage, R.N.; Gaikwad, H.P. (2019)

The ground-based all sky imager (ASI) is an advanced optical technique, capable of measuring the strong F-region nightglow in OI 630.0 nm emission from atomic oxygen. This emission is used to study the large-scale F-region ...
Airglow measurements of gravity wave propagation and damping over Kolhapur (16.5°N, 74.2°E)

Ghodpage, R.N.; Taori, A.; Patil, P.T.; Gurubaran, S.; Sharma, A.K.; Nikte, S.; Nade, D. (2014)

Simultaneous mesospheric OH and O (1S) night airglow intensity measurements from Kolhapur (16.8°N, 74.2°E) reveal unambiguous gravity wave signatures with periods varying from 01 hr to 9 hr with upward propagation. The ...
Alfvenic solitons in ultrarelativistic electron-positron plasmas

Lakhina, G.S.; Verheest, F. (1997)

In electron-positron plasmas some of the plasma modes are decoupled due to the equal charge-to-mass ratio of both species. We derive the dispersion law for a low-frequency, generalized X-mode, which exists at all angles ...
Alfvén modes in dusty cometary and planetary plasmas

Reddy, R.V.; Lakhina, G.S.; Verheest, F.; Meuris, Peter (1996)

Dusty plasmas contain charged dust grains which are much bigger than protons and usually carry high negative charges owing to preferential capture of electrons. These dust grains do not have a fixed charge, and perturbations ...
All-sky imaging observations of mesospheric fronts from Silchar (24.7°N, 92.8°E)

Chauhan, Nilesh; Gurubaran,S.; Moulik, S.; Das, P.K.; Bagiya, Mala S. (2022)

An All-Sky Airglow Imager was operated at Silchar (24.68°N, 92.76°E), India from 9 to 11 December 2018, during a special observational campaign. We report the presence of two simultaneous mesospheric fronts observed in OH ...
Altitude development of postmidnight F region field-aligned irregularities observed using Equatorial Atmosphere Radar in Indonesia

Dao, Tam; Otsuka, Yuichi; Shiokawa, Kazuo; Tulasiram, S.; Yamamoto, Mamoru (2015)

For the first time, vertical rise velocities of postmidnight field-aligned irregularities (FAIs) at low geomagnetic latitudes have been examined near the June solstice by using two-dimensional maps of F region FAI echoes ...
Amplitude enhancement of SC(H) events in the South Atlantic anomaly region

Trivedi, N.B.; Abdu, M.A.; Pathan, B.M.; Dutra, S.L.G.; Schuch, N.J.; Santos, J.C.; Barreto, L.M. (2005)

South Atlantic Magnetic Anomaly (SAMA) due to its weak total geomagnetic field F is known to be a sink of trapped charged particles from the inner radiation belt during both magnetically quiet and disturbed periods. ...
Analysis of plasma bubbles observed in night airglow emission line OI 630.0 nm from Kolhapur using all sky imager

Sharma, A.K.; Nade, D.P.; Nilte, S.S.; Ghodpage, R.N.; Patil, P.T.; Rokade, M.V.; Vhatkar, R.S. (2012)

All-sky imager (ASI) located at Kolhapur (16.8º N, 74.2º E), India is used to observe OI 630.0 nm night airglow emission (at an altitude 250 km) during clear moonless nights. To study the characteristics of night airglow ...
An analytic approach to toroidal eigen mode

Sinha, Ashwini K.; Rajaram, R. (1997)

It has been shown that the failure of the classical WKB approach in reproducing the correct frequency spectrum and spatial structures of field line resonances should be attributed to the inability of the method to provide ...
An analytic model of toroidal half-wave oscillations: Implication on plasma density estimates

Bulusu, Jayashree; Sinha, Ashwini K.; Vichare, Geeta (2015)

The developed analytic model for toroidal oscillations under infinitely conducting ionosphere (“Rigid-end”) has been extended to “Free-end” case when the conjugate ionospheres are infinitely resistive. The present direct ...

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