Ionospheric response of St. Patrick’s Day geomagnetic storm over Indian low latitude regions

• Published in: Astrophysics and space science 2022-10, Vol.367 (10), Article 103
• Main Authors: Chaurasiya, Sunil Kumar, Patel, Kalpana, Kumar, Sanjay, Singh, Abhay Kumar
• Format: Article
• Language: English
• Subjects: Astrobiology; Astronomy; Astrophysics; Astrophysics and Astroparticles; Auroral electrojet; Auroral electrojets; Cohabitation; Cosmology; Daytime; Electric fields; Electrojets; Equatorial ionization anomaly; Equatorial regions; Geomagnetic storm effects; Geomagnetic storms; Geomagnetism; Ionization; Ionospheric electron content; Ionospheric storms; Latitude; Longitude; Magnetic storms; Observations and Techniques; Penetration; Physics; Physics and Astronomy; Space Exploration and Astronautics; Space Sciences (including Extraterrestrial Physics; Storm effects; Storms; Total Electron Content; Wind effects
• ISSN: 0004-640X; 1572-946X
• DOI: 10.1007/s10509-022-04137-3

The current work shows the ionospheric response to an intense geomagnetic storm known as St. Patrick’s Day storm which occurred from 17-22 March 2015 using the ionospheric vertical total electron content data over the low latitude Indian stations. We have tried to study how it has influenced the vertical total electron content at four different low latitude stations: Varanasi (Geographic latitude 25°, 19’ N, longitude 82°, 59’ E), Lucknow (Geographic latitude 26°, 50’ N, longitude 80°, 55’ E), Bangalore (Geographic latitude 12°, 58’ N, longitude 77°, 35’ E), and Hyderabad (Geographic latitude 17°, 23’ N, longitude 78°, 27’ E). Various solar and geomagnetic parameters related to the geomagnetic storm have been analyzed to examine the consequences of geomagnetic storms on vertical total electron content. The analysis has been done on account of a comparison of mean total electron content estimated for geomagnetic quiet days and those during the period of the geomagnetic storm 17-21 March 2015. Analysis of vertical total electron content data during the storm period found a negative storm effect on 18 March during daytime at equatorial ionization anomaly station (Varanasi & Lucknow) and Positive storm effect at equatorial station (Hyderabad and Bangalore) which is in agreement with the results of Fagundes et al. ( 2015 ) reported in Brazil region. A strong positive storm effect in the daytime is noticed at EIA stations during 20-21 March which is higher at Lucknow (∼63 TECU) than that at Varanasi (∼37 TECU) whereas equatorial stations Bangalore and Hyderabad were found unaffected. The same results have also been reflected from total electron content data of single PRN 17. These positive and negative ionospheric storm effects observed during the geomagnetic storm have been explained using disturb dynamo electric field, prompt penetration electric field and neutral wind effects. The St. Patrick’s Day storm resulted in a minimum Disturbance Storm Time Index of −234 nT, Auroral Electrojet enhancement of up to 1000 nT, and a maximum enhancement of 33 percent of vertical total electron content (VTEC) values at Bangalore, an equatorial region, in comparison to average quiet days’ VTEC. This is known as the positive storm effect. The cohabitation of the prompt penetration electric field and the long-lasting disturbance dynamo electric field has caused the VTEC to respond favorably throughout the region and disturb dynamo electric field.