A correlation study regarding the AE index and ACE solar wind data for Alfvénic intervals using wavelet decomposition and reconstruction

Fernando L Guarnieri (1) , Bruce T Tsurutani (2) , Luis E A Vieira (1) , Rajkumar Hajra (3) , Ezequiel Echer (1) , Anthony Mannucci (2) , Walter D Gonzalez (1)

1 INPE - Instituto Nacional de Pesquisas Espaciais
2 JPL - Jet Propulsion Laboratory
3 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace

The purpose of this study is to present a wavelet interactive filtering and reconstruction technique and apply this to the solar wind magnetic field components detected at the L1 Lagrange point ∼ 0.01 AU upstream of the Earth. These filtered interplanetary magnetic field (IMF) data are fed into a model to calculate a time series which we call AE *. This model was adjusted assuming that magnetic reconnec-tion associated with southward-directed IMF B z is the main mechanism transferring energy into the magnetosphere. The calculated AE * was compared to the observed AE (auroral electrojet) index using cross-correlation analysis. The results show correlations as high as 0.90. Empirical removal of the high-frequency, short-wavelength Alfvénic component in the IMF by wavelet decomposition is shown to dramatically improve the correlation between AE * and the observed AE index. It is envisioned that this AE * can be used as the main input for a model to forecast relativistic electrons in the Earth's outer radiation belts, which are delayed by ∼ 1 to 2 days from intense AE events.

Domains: Geophysics [physics.geo-ph]; Space Physics [physics.space-ph]

Fernando L Guarnieri, Bruce T Tsurutani, Luis E A Vieira, Rajkumar Hajra, Ezequiel Echer, et al.. A correlation study regarding the AE index and ACE solar wind data for Alfvénic intervals using wavelet decomposition and reconstruction. Nonlinear Processes in Geophysics, 2018, 25 (1), pp.67-76. ⟨10.5194/npg-25-67-2018⟩. ⟨insu-01976508⟩