Speaker
Description
First Name: Akanksha
Last Name: Dagore
Affiliation: University of Trento, Italy, and University of Calabria, Italy
All Authors: Akanksha Dagore, Giuseppe Prete, Vincenzo Capparelli, Vincenzo Carbone, Fabio Lepreti
Abstract: Coronal Mass Ejections (CMEs) are large eruptions of plasma and magnetic flux from the Sun’s corona that play a key role in driving major space weather disturbances. In interplanetary space, they (ICMEs) often exhibit a forward shock, a compressed sheath, and a trailing magnetic cloud (MC) characterised by smoothly rotating, twisted magnetic fields (flux ropes). To investigate the evolution of turbulence across these regions, we applied Empirical Mode Decomposition (EMD) and Hilbert Spectral Analysis (HSA) to magnetic field components (Bx, By, Bz) from the 27 June 2013 ICME observed by NASA’s ACE spacecraft, capturing the nonlinear and non-stationary features intrinsic to real-time solar wind data. The Hilbert spectra showed the time-frequency distribution of amplitude, while the second-order marginal Hilbert spectra provided estimates of the spectral slopes within the inertial range. The solar wind preceding the CME shock shows a slope of −1.66±0.015 (Kolmogorov-like), steepening to −1.70±0.015 in the sheath and initial part of MC, and to −1.75±0.015 in the latter stage of MC and the trailing solar wind, indicating progressively enhanced turbulence. These results highlight the evolving nature of CME-induced turbulence and the effectiveness of EMD-HSA in capturing subtle features in CME dynamics. This work is currently under review for publication in Astronomy & Astrophysics.