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SEP Fe Charge State Distributions: Implications for Sources Mark Popecki 1, Eberhard Moebius 1 and Berndt Klecker 2 University of New Hampshire 1, MPE.

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Presentation on theme: "SEP Fe Charge State Distributions: Implications for Sources Mark Popecki 1, Eberhard Moebius 1 and Berndt Klecker 2 University of New Hampshire 1, MPE."— Presentation transcript:

1 SEP Fe Charge State Distributions: Implications for Sources Mark Popecki 1, Eberhard Moebius 1 and Berndt Klecker 2 University of New Hampshire 1, MPE 2

2 Fe Charge State Distributions for 4 Large SEP Events, Observed by ACE/SEPICA 1: Central disk event …Halo CME, X class flare at N20E18, cloud passage at Earth in latter part of event. 2: Halo CME, C class flare about 1 hour prior to the CME at N16W66 3: Central disk event…Halo CME, M class flare at S17W09, second ion injection (C & M class flare at N14W08 and N13W07), cloud passage at Earth during second injection. 4: Halo CME and a long series of flares in W hemisphere between N22W18 and N24W81; cloud passage at Earth in latter part of event Mean Q

3 Comparison of two events with: –a symmetrical and –a non-symmetrical Fe charge state distribution The central disk event has a charge state distribution similar to what is expected from a source at 1.0MK (IP shock only?) The event with a western flare has an extension to higher charge states (IP shock with flare component, reacceleration of flare ions?) The charge state distribution of an event with a high charge tail may be tested for the possibility of two concurrent sources: shock and flare-associated ions. Central disk event Event with a western flare prior to a halo CME Instrument Response with an Input Model

4 Inferred Input Fe Charge State Distributions 1: Central disk event …Halo CME, X class flare at N20E18, cloud passage at Earth in latter part of event. 2: Halo CME, C class flare about 1 hour prior to the CME at N16W66 3: Central disk event…Halo CME, M class flare at S17W09, second ion injection (C & M class flare at N14W08 and N13W07), cloud passage at Earth during second injection. 4: Halo CME and a long series of flares in W hemisphere between N22W18 and N24W81; cloud passage at Earth in latter part of event. The charge state distribution for ions entering the SEPICA instrument may be inferred by a forward modeling process that incorporates the instrument response with a sample charge state distribution. All four events feature a relatively narrow main peak. Three have various types of tails toward higher charge states. The event on 2000/95.9 (April 4, 2000) has a smoothly declining tail toward a charge state of 18+. In contrast, the events of 2000/256.9 (September 12.9, 2000) and 1998/310.0 (November 6, 1998) have a plateau, or possibly a second low peak, from charge states 12+ to ~

5 Empirical Flare Model An empirical model of a flare-related Fe charge state distribution was constructed from 6 flare events (Ho et al. (2001a, 2001b) Observations shown at right. This model can be used to test an observed charge state distribution for a plausible concurrent flare-related component.

6 Testing for two concurrent sources in the 98/310 event The empirical flare- associated model was combined with a 1.09MK thermal equilibrium model The combination is able to represent the peak and extended tail of the observed charge state distribution. This event featured a long series of flares in the western hemisphere. Observation space Flare-related source Equilibrium Temperature Source ACE News #127 11/2009

7 Summary Fe charge state distributions were shown for four large SEP events. The distribution for one event was similar to a source at 1MK, and was associated with a flare on the central region of the solar disk (00/159.0). –The similarity between the observed charge state distribution and a source at thermal equilibrium suggests that the ions reaching the instrument were accelerated with minimal collisional influence - high in the corona or in the IP medium. The other three events displayed high charge state tails and featured either a cloud passage associated with high charge states, or flares in the western hemisphere. –The high charge state tails suggest a relatively significant role for collisions during acceleration. –The Fe charge state distribution for the 98/310 event may be represented by a source at 1MK, plus another that is consistent with a flare population. –The other two events (00/95.9, 00/256.9): thermal equilibrium source plus a secondary source?


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