Diagnostics of magnetosphere-ionosphere coupling over Indian Antarctic station Maitri, from magnetometer and riometer observations during the optical auroral event of 4–5 March 1999

Abstract

A splendid display of “aurora australis” was observed over the Indian Antarctic station Maitri (geomag. lat. 62°.8 S, long. 52°.8 E; L = 4.8) on the night of 4–5 March 1999. The changes recorded by a fluxgate magnetometer, and a 30 MHz riometer operating at Maitri are interpreted in terms of currently - understood auroral physics. Interplanetary magnetic field and plasma parameters recorded by the WIND satellite indicate very high solar wind velocities (500–600 km/s), and prolonged southward Bz of average value (∼ 5 nT), during the auroral event. Ion density is however an average 3–4/cm3, and Ion pressure only 2–3 nano Pascals during the event.