High-cadence Hα imaging of solar flares

The Hα observation is a powerful tool to study the high-energy aspect of solar flares. Spiky brightenings of flare kernels at the Hα center reflect the rapid fluctuation in particle acceleration; linear polarization of Hα emission might be evidence of accelerated protons; red-shifts of the Hα line are caused by the chromospheric evaporation. To study the spiky brightenings of flare kernels with high-cadence imaging at the Hα center, a high-speed Hα camera for the Solar Flare Telescope at Mitaka, NAOJ, had been developed and it started the regular observation in 2001 July. However, the polarimetry and the Dopplermetry are also important and they are required to be carried out in parallel with the high-cadence imaging at the Hα center. Then, we upgraded the original high-speed Hα camera to a new Hα camera system for the multi-aspect Hα observations, which performs all of the high-cadence imaging, the linear polarization measurements, and the off-band imaging for velocity measurements. The new system started the observation in 2002 July. In this paper, the multi-aspect Hα imaging system is described and sample Hα images are presented.     

羊八井宇宙线强度观测数据的气压修正

分析了羊八井宇宙线强度的气压修正,分析表明,气压修正不仅与气压有关,而且与太阳活动有关。太阳活动最高的年,气压修正系数的绝对值最大。此外,计数率的修正值还与数据采样的时间间隔有关,即使是同一时间段,不同时间间隔采用率得到的修正值是不同的。本文最后分析了西藏羊八井中子监测器观测数据的气压修正,得到单路及八道多重计数的气压修正系数。     

Time distribution of the precipitable water vapor in central Saudi Arabia and its relationship to solar activity

Water vapor is the most important greenhouse gas. It plays a major role in the dynamics of atmospheric circulation, radiation exchange within the atmosphere, and climate variability. Knowledge of the distribution of water vapor is important for understanding climate change and global warming.     

Assessing the relationship between solar activity and some large scale climatic phenomena

The nature of the climatic response to solar variability is assessed over a long-time scale. The wavelet analysis applied to paleoclimatic proxy data of large scale atmospheric phenomena (North Atlantic Oscillation, Atlantic Multidecadal Oscillation, Pacific Decadal Oscillation and Southern Oscillation Index) has revealed coherence between the climatic oscillations and the solar phenomena (the cosmogenic isotope ¹⁰Be and the Total Solar Irradiance) preferentially with periods of Schwabe, Hale and Yoshimura–Gleissberg cycles that may reflect a modulation of solar activity.     

基于PCA方法对太阳活动区主要参量的分析

太阳耀斑与太阳质子事件的发生通常与太阳活动区存在非常密切的关系, 对这种关系的深入分析有助于太阳耀斑和太阳质子事件预报模型的建立. 本文利用主成分分析(Principal Component Analysis, PCA)方法对1997-2010年太阳质子事件所在活动区的主要参量进行分析, 选取的参量包括黑子磁分类、 McIntosh分类、太阳黑子群面积、10.7 cm射电流量、耀斑指数、质子耀斑位置和软X射线耀斑强度. 结果得到81个太阳活动主成分得分值排序(得分值代表每个事件的强弱), 与太阳质子事件峰值流量、太阳黑子年均值以及10.7 cm射电流量年均值的对比显示相似度非常高, 表明主成分得分值一定程度上可以反映太阳活动的强弱规律.     

Differential emission measure distributions in X-ray solar flares

X-ray spectrometer RESIK has observed spectra in the four wavelength bands from 3.3 Å to 6.1 Å. This spectral range contains many emission lines of H- and He-like ions for Si, S, Ar and K. These lines are formed in plasma of coronal temperatures (T > 3 MK). Analysis of their intensities allows studying differential emission measure distributions (DEM) in temperature range roughly between 3 MK and 30 MK. The aim of present study was to check whether any relationship exists between the character of DEM distribution, the event phase and the X-ray flare class. To do this we have calculated and analyzed the DEM distributions for a set of flares belonging to different GOES classes from the range B5.6–X1. The DEM distributions have been calculated using “Withbroe–Sylwester” multiplicative, maximum likelihood iterative algorithm. As the input data we have used absolute fluxes observed by RESIK in several spectral bands (lines + continuum). Respective emission functions have been calculated using the CHIANTI v. 5.2 atomic data package.     

Two-velocity structure observed in the inner solar wind

Measurements of the motion of plasma density inhomogeneities in the inner solar wind are presented. The speeds were estimated using a cross-correlation analysis of radio frequency fluctuations of the Galileo spacecraft measured simultaneously at widely spaced ground stations. The radial projections of the correlation baselines on the pattern plane were of the order of several thousand kilometers. For cross-correlation functions calculated with comparatively short averaging times, we find that a pronounced two-velocity configuration is occasionally observed over the range of heliocentric distances 20 R < R < 40 R. The typical mean speed for such observations is about 300–400 km/s and the difference between the two predominant speeds is about 150–200 km/s. These results may indicate that the density fluctuations are associated with slow magnetosonic waves propagating in opposite directions at the local speed of sound in the reference frame moving with the mean solar wind speed. Quite reasonable estimates of the solar wind speed and speed of sound are obtained from this model. Another possible explanation of the two-velocity structures is that two independent solar wind streams are present simultaneously along different segments of the radio ray path.     

SiCp/Al复合材料在太阳电池阵展开机构上的应用

介绍了SiCp/Al复合材料的机械性能、热力学性能、加工性能,以及在太阳电池阵展开机构中的应用情况。分析认为采用SiCp/Al复合材料,充分发挥了其高比模量、高比强度和良好的耐磨性能,其管材、型材已达到了应用阶段。