By use of the 2-m McMath-Pierce telescope at Kitt Peak, the high-quality spectra of a moderate-brightness plage near the center of solar disk were obtained. The data include seven spectral lines: Hα, Hβ, Call H and K lines and infrared triplet. Under the assumption of plane-parallel atmosphere, the hydrostatic, transfer and statistic equilibrium equations were solved iteratively and the semi-empirical model of the plage has been obtained. It can well reproduce the observed seven line profiles. The model has been compared with two existing plage models. Further improvement has also been discussed.
In this paper, the theory and method of the fuzzy mathematics areused to probe the connection between the activity of the active region and characterizat ion of the sunspot groups, to build the subordinating function according to the rela tionship between them and to evaluate comprehensively the activity of the active region on t he solar disk. The precise prediction of activity of the active regions has been obta ined by data reduction and analysis. The predicting accuracy is higher th an 95% . Forecast results indicate that the method of the fuzzy comprehensive evaluatio n is a good one for the solar activity prediction.
We briefly introduce our recent work on the spectral evolution of energetic protons, the beam property of accelerated electrons, the gamma-ray flare classification, the temporal features of the annihilation line, the hard X-ray delayed events, the hydrodynamic process, and the continuum emission in solar flares.
