Concept of the solar ring mission: An overview

The concept of the Solar Ring mission was gradually formed from L5/L4 mission concept, and the proposal of its pre-phase study was funded by the National Natural Science Foundation of China in November 2018 and then by the Strategic Priority Program of Chinese Academy of Sciences in space sciences in May 2019. Solar Ring mission will be the first attempt to routinely monitor and study the Sun and inner heliosphere from a full 360-degree perspective in the ecliptic plane. The current preliminary design of the Solar Ring mission is to deploy six spacecraft, grouped in three pairs, on a sub-AU orbit around the Sun. The two spacecraft in each group are separated by about 30° and every two groups by about 120°. This configuration with necessary science payloads will allow us to establish three unprecedented capabilities: (1) determine the photospheric vector magnetic field with unambiguity, (2) provide 360-degree maps of the Sun and the inner heliosphere routinely, and (3) resolve the solar wind structures at multiple scales and multiple longitudes. With these capabilities, the Solar Ring mission aims to address the origin of solar cycle, the origin of solar eruptions, the origin of solar wind structures and the origin of severe space weather events. The successful accomplishment of the mission will advance our understanding of the star and the space environment that hold our life and enhance our capability of expanding the next new territory of human.

     

不锈钢熔模铸造缺陷分析及质量控制

结合不锈钢熔模铸造生产实践中出现的铸造缺陷,如麻坑、黑点、凹陷、缩陷等,对其成因进行分析,并在此基础上提出熔模铸造过程中质量控制的关键环节,包括原材料控制,涂挂与脱蜡控制,熔炼与浇注控制等,结果发现麻坑缺陷产生的主要原因是面层型壳材料不合格,黑点是由于钢液中存在非金属夹杂物造成的,凹陷则是有由于微量的Ca、Mg导致Zr砂高温性能的下降,从而使型壳发生向内的膨胀变形,缩陷则和浇注温度过高有关等.     

Recent studies in satellite observations of three-dimensional magnetic reconnection

Magnetic reconnection is a main process converting the magnetic energy into thermal and kinetic energy in plasmas. It is one of the fundamental problems of crucial importance not only to space plasmas physics and space weather studies,such as the solar flare,coronal mass ejections and magnetospheric substorms,but also to the stability analysis in magnetically confined fusion. In general,except for cases with periodical boundary conditions,three-dimensional(3D) magnetic re-connection occurs on magnetic separatrices generated by magnetic nulls. Here we briefly introduce/review the theories and some recent satellite observations of 3D magnetic reconnection. Topics to be further studied are also discussed.