SIZE DISTRIBUTIONS OF SOLAR FLARES AND SOLAR ENERGETIC PARTICLE EVENTS

Journal Article · Mon Sep 10 04:00:00 EDT 2012 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/756/2/L29· OSTI ID:22078558

Cliver, E W ^[1]; Ling, A G ^[2]; Belov, A ^[3]; Yashiro, S ^[4]

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1. Space Vehicles Directorate, Air Force Research Laboratory, Sunspot, NM 88349 (United States)
2. Atmospheric Environmental Research, Lexington, MA 02421 (United States)
3. IZMIRAN, Troitsk, Moscow Region 142190 (Russian Federation)
4. NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

We suggest that the flatter size distribution of solar energetic proton (SEP) events relative to that of flare soft X-ray (SXR) events is primarily due to the fact that SEP flares are an energetic subset of all flares. Flares associated with gradual SEP events are characteristically accompanied by fast ({>=}1000 km s{sup -1}) coronal mass ejections (CMEs) that drive coronal/interplanetary shock waves. For the 1996-2005 interval, the slopes ({alpha} values) of power-law size distributions of the peak 1-8 A fluxes of SXR flares associated with (a) >10 MeV SEP events (with peak fluxes {>=}1 pr cm{sup -2} s{sup -1} sr{sup -1}) and (b) fast CMEs were {approx}1.3-1.4 compared to {approx}1.2 for the peak proton fluxes of >10 MeV SEP events and {approx}2 for the peak 1-8 A fluxes of all SXR flares. The difference of {approx}0.15 between the slopes of the distributions of SEP events and SEP SXR flares is consistent with the observed variation of SEP event peak flux with SXR peak flux.

• OSTI ID: 22078558
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 2 Vol. 756; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
79 ASTRONOMY AND ASTROPHYSICS
COSMIC PROTONS
DISTRIBUTION
MEV RANGE
PROTONS
SHOCK WAVES
SOFT X RADIATION
SOLAR CORONA
SOLAR FLARES