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Determination of the crystal elements' orientation arrangement in adjustable-wavelength birefringent filters
Abstracts
111
The Helmholtz instability of magnetic flux sheets AApS 11/4 (1991) 378-382 HU Wen-rui (Institute of Mechanics, Chinese Academy of Sciences) In the present paper, the Helmholtz instability is analyzed for the magnetic flux sheet, whose configuration consists of two discontinuous surfaces from a sheet magnetic flux region with &rite thickness confined by plasma on both sides. The instability condition for the case of sheet is obtained, and it agrees with that for the case of one discontinuous surface if the thickness of sheet tends to infinity. The dispersion conditions at two discontinuous surfaces are also given. The results show that the influence of magnetic stabilization in the case of sheet is relatively weaker than the case of one discontinuous surface, while the influence of confining plasma is relatively stronger, although the growth rates of instability for both cases have the same order of magnitude. Key words: Sun-MHD-plasma
Some features of solar microwave emissions of millisecond scale
time
AApS 11/4 (1991) 394-396 LI Xiao-tong WANG Shu-lan JI Hui-rong YAN Yuan-yi JIN Sheng-zhen ZHAO Bing (Beijing Astronomical Observatory, Chinese Academy of Sciences) Over one hundred “spike” and fine structure events, including some new features of microwave emissions, have been recorded since a new solar microwave polarimeter was put into operation at Beijing Astronomical Observatory in June 1990. Four types of the features are described in this paper:(l) narrow bandwidth emission, (2) fast polarization reversal, (3) fast frequency drift and (4) quasi-periodic oscillation. Key words: Sun-spike emission-fast fine structure
Determination of the crystal elements’ orientation arrangement in adjustable-wavelength birefringent Alters AApS 11/4 (1991) 383-388 AI Guo-xiang DENG Yuan-yong WANG Jing-shan (Beijing Astronomical Observatory, Chinese Academy of Sciences) This paper discusses several principles for the determination of the crystal elements’ orientation arrangement in adjustable-wavelength birefringent filters. By using these principles, we are able to determine the relations of the orientations among the birefripgent crystal plates, the wave plates and the rotated l/2 waveplates simply, clearly and accurately without any complicated mathematical calculations. Key words: Astronomical instrument-birefringent filter
111
The Helmholtz instability of magnetic flux sheets AApS 11/4 (1991) 378-382 HU Wen-rui (Institute of Mechanics, Chinese Academy of Sciences) In the present paper, the Helmholtz instability is analyzed for the magnetic flux sheet, whose configuration consists of two discontinuous surfaces from a sheet magnetic flux region with &rite thickness confined by plasma on both sides. The instability condition for the case of sheet is obtained, and it agrees with that for the case of one discontinuous surface if the thickness of sheet tends to infinity. The dispersion conditions at two discontinuous surfaces are also given. The results show that the influence of magnetic stabilization in the case of sheet is relatively weaker than the case of one discontinuous surface, while the influence of confining plasma is relatively stronger, although the growth rates of instability for both cases have the same order of magnitude. Key words: Sun-MHD-plasma
Some features of solar microwave emissions of millisecond scale
time
AApS 11/4 (1991) 394-396 LI Xiao-tong WANG Shu-lan JI Hui-rong YAN Yuan-yi JIN Sheng-zhen ZHAO Bing (Beijing Astronomical Observatory, Chinese Academy of Sciences) Over one hundred “spike” and fine structure events, including some new features of microwave emissions, have been recorded since a new solar microwave polarimeter was put into operation at Beijing Astronomical Observatory in June 1990. Four types of the features are described in this paper:(l) narrow bandwidth emission, (2) fast polarization reversal, (3) fast frequency drift and (4) quasi-periodic oscillation. Key words: Sun-spike emission-fast fine structure
Determination of the crystal elements’ orientation arrangement in adjustable-wavelength birefringent Alters AApS 11/4 (1991) 383-388 AI Guo-xiang DENG Yuan-yong WANG Jing-shan (Beijing Astronomical Observatory, Chinese Academy of Sciences) This paper discusses several principles for the determination of the crystal elements’ orientation arrangement in adjustable-wavelength birefringent filters. By using these principles, we are able to determine the relations of the orientations among the birefripgent crystal plates, the wave plates and the rotated l/2 waveplates simply, clearly and accurately without any complicated mathematical calculations. Key words: Astronomical instrument-birefringent filter