Very low latitude whistlers (L = 1.08): arrival azimuth determination

Abstract

Since last four decades and more generation and propagation mechanism of very low latitude (L < 1.4) whistlers has been studied by many workers in lowlatitude regions and especially in India. The key questions that remain unanswered include: (1) Where are the lightning discharges, the source of whistlers located? (2) Do the whistler waves at low latitudes propagate along the magnetic field lines in low latitude ionosphere? We reported that the lightning discharges that have generated whistlers are located in the conjugate region in the Indian Ocean and suggested the whistlers at these stations propagate along the magnetic field lines in the low latitude ionosphere. In this communication, we present the arrival azimuth determination technique adopted to confirm the location of the lightning discharges which generated the observed whistlers and the technique is validated with real-time lightning data. The technique adopted to determine the arrival azimuths of low latitude whistler causative lightning discharges is of significance and will help in resolving the unanswered questions of low latitude whistler phenomena.