中文摘要：

太阳过渡区是太阳色球层顶到日冕底部的大气薄层。厚度仅几百千米,但其间太阳等离子体参数变化剧烈。过渡区的辐射多为光学薄的远紫外、极紫外发射谱线和背景连续谱线。由于地球大气的吸收,过渡区紫外光谱需通过天基观测才能实现。近几十年来,星载仪器的成功发射为太阳过渡区的研究打开了新纪元。工作回顾了太阳过渡区紫外光谱的观测历史和各类星载仪器,特别介绍了近十几年几种重要的光谱仪器。详细阐述了过渡区紫外光谱的发生率、电子密度和电子温度的诊断原理。讨论了过渡区紫外谱线的形状,并以SOHO/SUMER光谱仪为例介绍了表征谱线的几种重要参量及其物理意义。

英文摘要：

The solar transition region is the thin atmosphere layer between the chromosphere and corona.Although the thicknessof the solar transition region is only several hundred kilometers,the parameters of the plasma change dramatically.The tempera-ture increases from 104 to 106 K and the density drops from 1010 to 108 cm-3.The emission of the solar transition region is gener-ally of optical-thin far-ultraviolet（FUV）spectral lines,extreme-ultraviolet（EUV）spectral lines and background continuousspectral lines.However,the traditional ground-based observations can not be made for FUV/EUV lines,owing to their strongabsorption by ozone and other molecules in the earth’s atmosphere.Thus,FUV/EUV lines only can be obtained with space-based observations.In recent decades,the successful launch of space-borne instruments opened a new era of the research for thesolar transition region.The present paper reviews the observation history of ultraviolet spectra in the solar transition region andsome kinds of space-borne instruments,especially several important spectrometers in recent ten years.At the same time,thediagnostics of the emissivity,electron density and electronic temperature of ultraviolet spectra in the solar transition region areexpounded in detail.The shape of ultraviolet line is discussed and several important parameters with physical significance areshowed using SOHO/SUMER spectrometer.