TY - JOUR

T1 - Solar Energetic Particle Events in the 23rd Solar Cycle: Interplanetary Magnetic Field Configuration and Statistical Relationship with Flares and CMEs

AU - Miteva, R.

AU - Klein, K. -L.

AU - Malandraki, O.

AU - Dorrian, G.

PY - 2013/2

Y1 - 2013/2

N2 - We study the influence of the large-scale interplanetary magnetic field configuration on the solar energetic particles (SEPs) as detected at different satellites near Earth and on the correlation of their peak intensities with the parent solar activity. We selected SEP events associated with X-and M-class flares at western longitudes, in order to ensure good magnetic connection to Earth. These events were classified into two categories according to the global interplanetary magnetic field (IMF) configuration present during the SEP propagation to 1 AU: standard solar wind or interplanetary coronal mass ejections (ICMEs). Our analysis shows that around 20 % of all particle events are detected when the spacecraft is immersed in an ICME. The correlation of the peak particle intensity with the projected speed of the SEP-associated coronal mass ejection is similar in the two IMF categories of proton and electron events, approximate to 0.6. The SEP events within ICMEs show stronger correlation between the peak proton intensity and the soft X-ray flux of the associated solar flare, with correlation coefficient r = 0.67 +/- 0.13, compared to the SEP events propagating in the standard solar wind, r = 0.36 +/- 0.13. The difference is more pronounced for near-relativistic electrons. The main reason for the different correlation behavior seems to be the larger spread of the flare longitude in the SEP sample detected in the solar wind as compared to SEP events within ICMEs. We discuss to what extent observational bias, different physical processes (particle injection, transport, etc.), and the IMF configuration can influence the relationship between SEPs and coronal activity.

AB - We study the influence of the large-scale interplanetary magnetic field configuration on the solar energetic particles (SEPs) as detected at different satellites near Earth and on the correlation of their peak intensities with the parent solar activity. We selected SEP events associated with X-and M-class flares at western longitudes, in order to ensure good magnetic connection to Earth. These events were classified into two categories according to the global interplanetary magnetic field (IMF) configuration present during the SEP propagation to 1 AU: standard solar wind or interplanetary coronal mass ejections (ICMEs). Our analysis shows that around 20 % of all particle events are detected when the spacecraft is immersed in an ICME. The correlation of the peak particle intensity with the projected speed of the SEP-associated coronal mass ejection is similar in the two IMF categories of proton and electron events, approximate to 0.6. The SEP events within ICMEs show stronger correlation between the peak proton intensity and the soft X-ray flux of the associated solar flare, with correlation coefficient r = 0.67 +/- 0.13, compared to the SEP events propagating in the standard solar wind, r = 0.36 +/- 0.13. The difference is more pronounced for near-relativistic electrons. The main reason for the different correlation behavior seems to be the larger spread of the flare longitude in the SEP sample detected in the solar wind as compared to SEP events within ICMEs. We discuss to what extent observational bias, different physical processes (particle injection, transport, etc.), and the IMF configuration can influence the relationship between SEPs and coronal activity.

KW - CORONAL MASS EJECTIONS

KW - Coronal mass ejections, interplanetary

KW - SOHO

KW - CATALOG

KW - PROTON FLUXES

KW - Energetic particles

KW - REGIONS

KW - Magnetic fields, interplanetary

KW - SPACECRAFT

KW - RAYS

KW - SUN

U2 - 10.1007/s11207-012-0195-2

DO - 10.1007/s11207-012-0195-2

M3 - Journal article

VL - 282

SP - 579

EP - 613

JO - Solar Physics

JF - Solar Physics

SN - 0038-0938

IS - 2

ER -