Auroral substorm dynamics and field line resonances
© The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS); The Seismological Society of Japan; The Volcanological Society of Japan; The Geodetic Society of Japan; The Japanese Society for Planetary Sciences. 2002
Received: 24 April 2002
Accepted: 27 August 2002
Published: 21 June 2014
Magnetospheric substorms frequently have oscillating auroral phenomena associated with them, and which may be related to field line resonances. In this paper we present an analysis of photometer data which displays such oscillations in luminosity. We use data from the Gillam station in the CANOPUS array for April 1, 2000. Clear pulsations in magnetometer and photometer data are observed at 2.2 mHz. The latitudinal distribution of the photometer pulsations indicates that the auroral luminosity variations, caused by precipitating electrons and protons, are modulated by large scale global compressional modes (field line resonances). The proton and electron auroras were found to oscillate essentially out of phase. As well, the variation of phase across the peak in the luminosity resonance follows the pattern expected for the coupling of resonant Alfve’n modes by normal compressional modes in the magnetotail.