March 3 (Tue.)/ G1-2

The 3rd AOSWA Workshop
March 2-5 2015
Fukuoka, Japan

Characteristics ofFour SPE Classes
according to onset timing
and proton acceleration pattern
R.-S. Kim1, K.-S. Cho1, J. Lee2, S.-C. Bong1, and Y.-D. Park1
1Korea Astronomy and Space Science Institute2Chungnam National University, Korea

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A refined classification of SPEs (Kim et al., 2015, JGR)
 Data and methods• 42 SPEs observed with SOHO/ERNE multi-energy channel detector from 1997 to 2012
• Velocity dispersion analysis: estimation of the SPE onset times at the solar vicinity• Onset time comparison: SPEs, and associated flares, CMEs, and type II radio bursts.

1.2AUA refined classification of SPEs (Kim et al., 2015, JGR) Main result• SPE classification by two criteria of– SPE onset timing relative to flare peak time
– Energy-dependent proton flux enhancement (𝑇𝐻 − 𝑇𝐿 )• Group A– Proton flux increases during the flare X-ray intensity is increasing .
– Flux enhancements starting from the lower energy– Large flux enhancements occur in a short time
• Groups B and C– Well coincident onsets with the first appearance of CMEs in LASCO FOV.
– Relatively weak and slow flux enhancements• Group D– Immediate flux enhancement in all energy channels within ~2 min.

Characteristics of four SPE classes
 Are there any typical characteristics of associated events and acceleration sites in each group?
• SPE: proton flux and (TH-TL)• Flare: X-ray intensity and longitude• CME: angular width and speed• Acceleration Heights of SPEand type II radio burstSPE intensity and the onset time difference, 𝑇𝐻 − 𝑇𝐿

 𝑇𝐻 − 𝑇𝐿 : Onset time difference between the highest and the lowest energy channels• 𝑇𝐻 − 𝑇𝐿 > 0 : Acceleration started first in the lower energy channel and later in higherenergy• 5 strongest SPEs above 104 pfu have positive values and are classified into groups A or C.
• Extended duration events: the exceptional 3 events of group C show very weak fluxenhancements.

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Associated Flare Flare intensity• Mean values of X-ray intensity is the strongest for group D and the weakest for group B.
 It is hard to find any strong group dependence on the X-ray intensity.
 Flare location• Groups A and D have flaring sites close to the western limb.
 Relatively short intervals between high and low energy channels, 𝑇𝐻 − 𝑇𝐿
• Groups B and C show wider distribution of flaring sites.
 This tendency confirms that flare associated SPEs are relatively more connected from thefoot-point of the interplanetary (IP) magnetic field line to the spacecraft.

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Associated CME
 Angular width• Groups B and D: most of them are associated with full halo CMEs (mean=350˚ and 337˚)• Groups A and C: mean=274˚ Even the partial halo CMEs can accelerate protons under the certain conditions.
 Or flare association? : acceleration pattern starts from the lower energy channel.
 Speed• Mean speed for group D is the fastest among all events with the value of 1855 km/s,
however, the distribution seems to be roughly scattered.

Acceleration Heights
 Hp and He• Heights of CME front edge at the onset times of proton acceleration (Hp) and type II burst(He) based on the extrapolation of LASCO observation.
 Only for group A• Hp is lower than 1 Rs and Hp < He.
• Hp < 1 the event might have no relation with CME.
 The other events in groups B, C, and D• He is increasing according to the groups, however Hp is not.
• SPEs in groups B and C are located beneath the line.
 Proton acceleration follows after the electron acceleration.

Typical Characteristics of Groups Group A• Strong SPE flux in spite of week X-ray intensity.
• Its CME properties of speed and angular width are also weaker than average values.
• It is clear that those events are associated with flares since their low acceleration heightand western biased longitudes.
 Group B• CME biased properties - weak flare and SPE intensities, but wide angular width and fast
speed with higher proton acceleration site and wider longitude of flaring site.
 Group C• Strong SPE intensity in spite of weak flareand CME.
 Group D• Association with very strong flares andCMEs.
• Acceleration sites of proton and electron
are relatively higher.
• However the proton intensity is very weak.

Summary If the proton acceleration starts from a lower energy (Group A and C), A SPE has a higher chance to be a strong event (> 5000 pfu) even if the associated flareand CME are not so strong.
• Group A: acceleration sites are very low ( ~1 Rs) and close to the western limb.
• Group C: relatively higher (mean=6.05 Rs) and wider acceleration sites.
 When the proton acceleration starts from the higher energy (Group B),
 A SPE tends to be a relatively weak event (< 1000 pfu), in spite of its associated CME isrelatively stronger than previous group.
 SPEs with simultaneous acceleration in whole energy range within 10 minutes (Group D)
 Acceleration heights are very close to the locations of type II radio bursts.
 Weakest proton flux (mean=327 pfu) in spite of strong related eruptions.