An explanation for large enhancements of nitrogen relative to carbon and oxygen in solar 3He-rich events

Preferential heating and abundance enhancements of carbon (C), nitrogen (N), and oxygen (O) in solar He-3-rich energetic particles are investigated in terms of the two-stage acceleration model proposed by Zhang. It is shown that C+5, N+6, and O+7 are preferentially heated by H-cyclotron waves with a frequency close to twice the He-3-cyclotron frequency through the third harmonic resonance. If the initial electron temperature of the solar corona is in the range of similar to2-3.2 MK, the abundance of N in high-energy particles due to the second-stage acceleration is enhanced by a factor of similar to4-12 relative to C and O. The abundance pattern of C, N, and O obtained from the two-stage acceleration model is consistent with recent measurements (Mason, Mazur, & Dwyer). In addition, harmonic resonances of neon, silicon, magnesium, sulfur, calcium, and iron with the H-cyclotron waves are discussed.