Spatio‐temporal entropy analysis of the magnetic field to help magnetic cloud characterization
Year: 2013
Type: article
Abstract: The aim of this work is to create a methodology to characterize the dynamics of magnetic clouds (MCs) from signals measured by satellites in the interplanetary medium. We have tested spatio‐temporal entropy (STE) technique to study 41 MCs identified by other authors, where the plasma sheath region has been identified. The STE was implemented in Visual Recurrence Analysis software to quantify the order in the recurrence plot. Some tests using synthetic time series were performed to validate the method. In particular, we worked with interplanetary magnetic field (IMF) components Bx, By, Bz of 16 s. Time windows from March 1998 to December 2003 for some MCs were selected. We found higher STE values in the sheaths and 0 STE values in some of the three components in most of the MCs (30 among 41 events). The trend is the principal cause of the lower STE values in the MCs. Also, MCs have magnetic field more structured than sheath and quiet solar wind. We have done a test considering the magnetic components of a cylindrically symmetric force‐free field constructed analytically, with the result of 0 STE value. It agrees with the physical assumption of finding 0 STE values when studying experimental data in MC periods. The new feature just examined here adds to the usual features, as described in Burlaga et al. (1981), for the characterization of MCs. The STE calculation can be an auxiliary objective tool to identify flux ropes associated with MCs, mainly during events with no available plasma data but only with IMF.
DOI: 10.1002/jgra.50504
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W1769733292