The Magnetic and Optical Signature of a Pg Pulsation
Planetary and Space Science
A giant pulsation (Pg), observed on two magnetometer arrays in Northern Europe, has been analysed. The integrated video records from an all-sky TV camera that had been recording pulsating aurora concurrently, had an identical periodicity to the Pg. Complex demodulation analysis of the event has yielded the amplitude, phase and polarization characteristics of the wave packet. The dominant East-West (D) component wave signature in amplitude and phase suggests that this Pg has guided poloidal mode characteristics. On the basis of equatorial mass density calculations it is shown that the Pg is most likely to be a second harmonic oscillation. The bounce resonance instability with 17 keV protons is discussed as being a possible candidate for the generation of the Pg. The mechanism of Coroniti and Kennel (1970, J. geophys. Res. 75, 1279) is discussed as being the most likely mechanism for the generation of the pulsating aurora seen on this night.
Chisham, G., D. Orr, M.J. Taylor, and H. Luhr, The magnetic and optical signature of a Pg pulsation, Planet. Space Sci., 38, 1443, 1990.