摘要
Solar eruptive events,like flares and coronal mass ejections,are characterized by the rapid release of energy that can give rise to emission of radiation across the entire electromagnetic spectrum and to an abrupt significant increase in the kinetic energy of particles.These energetic phenomena can have important effects on the space weather conditions and therefore it is necessary to understand their origin,in particular,what is the eruptive potential of an active region(AR).In these case studies,we compare two distinct methods that were used in previous works to investigate the variations of some characteristic physical parameters during the pre-flare states of flaring ARs.These methods consider:i)the magnetic flux evolution and magnetic helicity accumulation,and ii)the fractal and multi-fractal properties of flux concentrations in ARs.Our comparative analysis is based on time series of photospheric data obtained by the Solar Dynamics Observatory between March 2011 and June 2013.We selected two distinct samples of ARs:one is distinguished by the occurrence of more energetic M-and X-class flare events,that may have a rapid effect on not just the near-Earth space,but also on the terrestrial environment;the second is characterized by no-flares or having just a few C-and B-class flares.We found that the two tested methods complement each other in their ability to assess the eruptive potentials of ARs and could be employed to identify ARs prone to flaring activity.Based on the presented case study,we suggest that using a combination of different methods may aid to identify more reliably the eruptive potentials of ARs and help to better understand the pre-flare states.
基金
received funding from the European Commission’s Seventh Framework Programme under the grant agreements e HEROES(project No.284461)
F-Chroma(project No.606862)
SOLARNET project(No.312495)
from the European Union’s Horizon 2020 research and innovation programme under the grant agreements(PRE-EST project,No.739500)and SOLARNET project(No.824135)
support by the Universitàdegli Studi di Catania(Piano per la Ricerca Universitàdi Catania 2016-2018–Linea di intervento 1“Chance”
Linea di intervento 2“Dotazione ordinaria”
Fondi di Ateneo 20202022,Universitàdi Catania,Linea Open Access)
by the Istituto Nazionale di Astrofisica(INAF)
by the Italian MIUR-PRIN grant 2017APKP7T on“Circumterrestrial Environment:Impact of Sun-Earth Interaction”
by Space Weather Italian COmmunity(SWICO)Research Program
the Science and Technology Facilities Council(STFC),(UK,Aberystwyth University,Grant No.ST/S000518/1),for the support received while carrying out this research
the STFC(UK),Grant No.ST/M000826/1)for the support received
the support received by the Royal Society(Grant No.IE161153)
by the CAS President’s International Fellowship Initiative(Grant No.2019VMA052)。
