Physics
Scientific paper
Dec 2006
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006agufmsh43b1512z&link_type=abstract
American Geophysical Union, Fall Meeting 2006, abstract #SH43B-1512
Physics
7509 Corona, 7514 Energetic Particles (2114), 7519 Flares, 7554 X-Rays, Gamma Rays, And Neutrinos, 7867 Wave/Particle Interactions (2483, 6984)
Scientific paper
Two distinct classes of impulsive and gradual solar energetic particle events have been recognized (Reames, ApJ, 571, L63, 2002). The impulsive events are characterized by 1) abundance enhancements of 3He/4He by a factor of ~ 104, Fe/O by a factor of ~ 10 in Fe/O, ^{22}Ne/20Ne by a factor of ~ 2-3, and (Z > 50)/O by a factor of ~ 102 -104, 2) high charge states of ions, 3) short durations (a few minutes to several hours), 4) small but frequently occurred events ( ~ 1000 per year), and 5) type-III radio bursts. The gradual events are characterized by 1) coronal mass ejection associations, 2) normal abundances and charge states of ions, 3) long durations (several hours to days), 4) large but rarely occurred events (~ 10 per year), and 5) type-I, IV radio bursts. Some solar gradual events can be superhot with temperature up to ~ 40 MK and contain both impulsive and gradual phases, so that these events have the features of both the impulsive and gradual events such as the RHESSI observed 2002 July 23 event (Lin et al., ApJ, 595, L69, 2003). Based on Cartwright and Mogro-Campero (ApJ, 177, L43, 1972) scenario and Fisk (ApJ, 224, 1048, 1978) efforts, Zhang (ApJ, 449, 916, 1995; ApJ, 518, 954, 1999) developed a complete two-stage acceleration model for solar impulsive or 3He-rich events. Plasma waves with frequency close to the harmonics of the 3He- cyclotron frequency efficiently heat 3He and heavy ions with appropriate charge states through the harmonic resonances and electrons through Landau resonances. The preheating of ions significantly increases the number of them that are injected into the flare-acceleration processes, and therefore lead to the enhancements of the ions in solar energetic particle events. The two-stage acceleration model has self- consistently explained various aspects of accelerations of ions and electrons in solar 3He-rich events (Zhang, JGR, 108A, SSH6Z, 2003; ApJ, 617, L77, 2004; Zhang and Wang, ApJ, 588, L57, 2003; ApJ, 613, L165, 2004; Zhang et al., JGR, 110A, 12111, 2005). The predictions on the enhancements of 3He/4He, Fe/O, ^{22}Ne/20Ne, and (Z>50)/O, the high charge states of Si, and Fe, the energy spectra of electrons, ions, and hard X-rays in the impulsive or 3He-rich solar energetic particle events agree with the measurements. In this presentation, we will overview the two-acceleration mechanism for the impulsive solar energetic particle events and reveal its further theoretical developments and observational demonstrations.
Tan Aihong
Wu Seongho
Zhang Tianmeng
No associations
LandOfFree
Two-Stage Acceleration Mechanism for Impulsive Solar Energetic Particle Events does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Two-Stage Acceleration Mechanism for Impulsive Solar Energetic Particle Events, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Two-Stage Acceleration Mechanism for Impulsive Solar Energetic Particle Events will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-968446