Semi-empirical model of solar plages

By use of the 2-m McMath-Pierce telescope at Kitt Peak, the high-quality sp ectra of a moderate-brightness plage near the center of solar disk were obt ained, The data include seven spectral lines: H alpha, H beta, Call H and K lines and infrared triplet. Under the assumption of plane-parallel atmosph ere, the hydrostatic, transfer and statistic equilibrium equations were sol ved iteratively and the semi-empirical model of the plage has been obtained . It can well reproduce the observed seven line profiles. The model has bee n compared with two existing plage models. Further improvement has also bee n discussed.