Power spectra of segmentation-cell length (a dominant length scale of EUV emission in the transition region) from full-disk HeII extreme ultraviolet (EUV) images observed by the Extreme ultraviolet Imaging Telescope (EIT) onboard the Solar and Heliospheric Observatory (SOHO) and the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) during periods of quiet Sun conditions for a time interval from 1996 to 2015 were analyzed. The spatial power as a function of the spatial frequency from about 0.04 to 0.27 (EIT) or up to 0.48 (AIA) 1/Mm depends on the distribution of the observed segmentation-cell dimensions, -- a structure of the solar EUV network. The temporal variations of the spatial power reported by Didkovsky and Gurman (Solar Phys., 289, 153) were suggested as decreases at the mid-spatial frequencies for the compared spectra when the power curves at the highest spatial frequencies of 0.5 1/pix were adjusted to match each other. That approach has been extended in this work to compare spectral ratios at high spatial frequencies expressed in the solar spatial frequency units of 1/Mm. Based on this approach we represent these ratio changes as a long-term network transformation which may be interpreted as a continuous dissipation of mid-size network structures to the smaller-size structures in the transition region. In contrast to expected cycling of the segmentation-cell dimension structures and associated spatial power in the spectra with the solar cycle, the spectra demonstrate a significant and steady change of the EUV network. The temporal trend across these structural spectra is not critically sensitive to any long-term instrumental changes, e.g. degradation of sensitivity, but to the change of the segmentation-cell dimensions of the EUV network structure.
Influence of Cross-sectional Expansion on Coronal Emissions from a Radiatively Cooling Solar Flare Loop
School of Astronomy and Space Science, Nanjing University（南京大学天文与空间科学学院）；Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education（教育部现代天文学和天体物理学重点实验室（南京大学））
The morpho-kinematical structure and chemical abundances of the complex planetary nebula NGC 1514
我们目前的高分辨率，长缝光谱和图像的行星状星云NGC1514。[OIII]发射线的位置速度图揭示了具有多种结构的复杂运动学。一个形态运动学分析表明，内壳，最初是球形的，现在扭曲的几个气泡，和一个附加的外壳。在我们的高分辨率长缝光谱中没有检测到NGC1514的两个定义明确的中红外环，这使我们无法对它们进行运动学分析。完全基于它们的形态，我们提出了一个桶状结构来解释环。星云的形成可能涉及几个喷射过程，尽管很难用现有的数据建立时间顺序。我们还分析了中等分辨率，长缝光谱的目的是研究的物理参数和化学丰度的NGC1514。星云光谱显示了一个中等激发的星云，具有[ArIII]，[NeIII]，HeI和HeII的弱发射线。没有[NII]，也没有检测到其他低激发发射谱线。我们发现在气体中的电子温度约为14000 K，电子密度在2000和4000 cm $^{-3}$的范围内。
Radio Diagnostics of Particle Acceleration in Solar Flares with SKAO Observations
Indian Institute of Technology Kanpur（坎普尔印度理工学院）；New Jersey Institute of Technology（新泽西理工学院）；University College London（伦敦大学学院）；University of Glasgow（格拉斯哥大学）
