共查询到20条相似文献，搜索用时 93 毫秒
1.
与太阳射电爆发相比,通常认为频率较低的行星际射电爆发产生于远离低日冕的行星际空间.地球电离层的截止导致地基设备无法对其进行观测.美国国家航空航天局(National Aeronautics and Space Administration, NASA)发射的帕克太阳探测器(Parker Solar Probe, PSP)是迄今为止距离太阳最近的空间探测器.其搭载的射电频谱仪能够对10 k Hz–19.17 MHz频段范围内的射电辐射进行观测. PSP能够靠近甚至可能穿越行星际III型射电爆发的辐射源区,因此使用PSP对行星际射电爆发进行观测具有前所未有的优势.简要介绍了目前为止使用PSP的射电观测数据对行星际III型射电爆发的多方面研究,包括爆发的发生率、偏振、散射、截止频率、可能的辐射机制和相关的辐射源区等方面的研究进展,并讨论了其未来的研究前景. 相似文献
2.
本文阐述了在二十一太阳周期上升相期间太阳黑子、钙谱斑、2800MHz射电流量和太阳耀斑、质子耀斑、质子事件的活动情况。我们的统计结果表明,在这个时段,太阳活动通过三次脉冲性上升达到极大。 本文确定了上升相的活动经度:L160°～210°和L50°～90°。并对最强的活动区进行了讨论。 相似文献
3.
云南天文台高分辨率射电频谱仪观测到10毫秒级变周期振荡,带宽约10MHz,叠加在一个持续时间约500ms的射电频谱上.在德国Weissenau的太阳射电频谱记录上找到了对应的爆发;同时SESC(美国空间环境服务中心)发表了同一时刻获得的245MHz总强度射电爆发记录;还在日面城到了相应的H_α亮点. 相似文献
4.
研究发现,太阳自转速率的变化与太阳活动之间存在一定的联系,但是不同学者的研究结论存在着矛盾:有的认为两者为正相关,而有的却认为是负相关.究竟两者之间是什么关系,需要做进一步深入的分析.利用EEMD (Ensemble Empirical Mode Decomposition)等方法对太阳自转速率和太阳黑子数据序列进行相关关系以及相位关系的计算和分析,以探讨太阳自转速率变化与太阳活动之间的关系.研究发现:两者的长期趋势项分量呈显著负相关;在11 yr左右周期分量上,观测到的太阳自转速率滞后太阳黑子的变化约2 yr时,呈显著负相关关系,超前3 yr时呈现次显著的正相关;对太阳活动第12–23周各周内部太阳黑子与太阳自转速率的相关分析表明,两者的关系比较复杂,但负相关关系更为显著.这为进一步理解太阳活动变化与太阳自转速率变化之间的成因联系提供了新的依据. 相似文献
5.
太阳总辐照在23和24太阳活动周的显著周期分别为35 d和26 d,进而推断太阳的准旋转周期在23和24太阳活动周也分别为35 d和26 d.太阳总辐照在24周极小期的值可能与蒙德极小期的值相近.在一个太阳旋转周到几个月的时间尺度上,太阳黑子是引起太阳总辐照变化的主要原因,但不是唯一的原因;在几天到一个太阳旋转周的时间尺度上,太阳总辐照的变化与MgⅡ特征指数是不相关的. 相似文献
6.
基于多波段的观测数据, 研究了黑子本影振荡在太阳大气不同高度或温度的振荡特征. 目标黑子发生在2017年9月15日, 位于活动区12680. 多波段的观测数据包括AIA (Atmospheric Imaging Assembly)的极紫外成像及IRIS (Interface Region Imaging Spectrograph)的紫外光谱和成像. 在太阳黑子的本影位置, AIA 1700 Å 光变曲线的振荡周期约为(4.2士0.8) min,而AIA 1600 Å、171 Å和193 Å光变曲线的振荡周期约为(2.8士0.3)min. IRIS的Mg II h和k谱线及远紫外成像(2796 Å)都表现为(3.1士0.5) min的准周期振荡,而谱线Si IV 1393.76 Å的振荡周期约为(2.9+0.4)min.观测结果说明黑子本影的振荡周期随着太阳大气高度的升高而逐渐减小.较短的周期可认为是3 min振荡,很可能与黑子本影上方的慢磁声波有关,它起源于温度极小区并向上传播到日冕.较长的周期可解释为光球的5 min振荡,与太阳的P模振荡有关. 相似文献
7.
太阳和地磁活动中的1.3–1.7 yr周期研究对于理解日地空间耦合系统中可能发生的物理过程十分重要.黑子是太阳光球层上最突出的磁场结构, Ap指数则是表征全球地磁活动水平的重要指标.使用同步压缩小波变换得到太阳黑子数和地磁Ap指数的1.3–1.7yr周期,并用互相关方法分析研究它们之间的相位关系.结果如下:(1)太阳黑子数和地磁Ap指数的1.3–1.7 yr周期呈现间歇性的演化特征,且随着时间的变化而不断变化;(2)地磁Ap指数在奇数活动周比相邻的偶数活动周的周期分量更高,表现出上下波动的变化特性;(3)地磁Ap指数和太阳黑子数的相位关系不是一成不变的,在大多数情况下地磁Ap指数滞后太阳黑子数,仅在第18和第22活动周黑子数在相位上滞后. 相似文献
8.
太阳射电爆发(Solar Radio Burst, SRB)是太阳高能电子与背景等离子体相互作用产生的感应辐射现象,其多样的动力学谱类型及其复杂的精细结构反映了辐射源区磁等离子体结构状态丰富的物理信息,而相关辐射机制则是解读相关物理信息的关键工具.长期以来,在SRB辐射机制的研究中一直存在着争议不决的两种主要机制,即等离子体辐射机制和电子回旋脉泽(Electron Cyclotron Maser, ECM)辐射机制.近年来,针对传统的ECM辐射机制应用到SRB现象时遇到的一些主要困难,发展了由幂律谱电子低能截止驱动和包含快电子束自生阿尔文波效应的新型ECM驱动模型,并成功应用于解释各类不同SRB动力学谱的形成机制.基于这些新型的ECM辐射模型,系统地总结了ECM辐射机制在各种不同类型SRB现象中的应用,并对它们不同动力学谱结构的形成给出了一致统一的物理解释. 相似文献
9.
介绍了低频射电干涉阵的发展情况、研究领域,讨论了国际上的LOFAR、LWA和MWA等低频射电项目.借鉴当今的低频射电项目,结合云南的地理和太阳射电优势,设想在云南省内构建一个太阳低频射电干涉阵,观测频率在30 MHz～250 MHz范围内,文中仿真了太阳低频射电干涉阵(4台站),比较和分析了通过优化算法得到的阵列的UV覆盖、脏束(Dirty beam);讨论了低频射电干涉阵的观测模式、射电干扰、低频射电成像等问题;分析低频射电阵在观测太阳爆发性活动产生的日冕物质抛射(Coronal Mass Ejections,CME)、耀斑、射电爆发的可能性;通过上述的仿真和分析构建太阳低频射电干涉阵面临的问题,可以为今后建立阵列提供依据. 相似文献
10.
11.
The wavelet analysis of the period of solar activity 总被引：1，自引：0，他引：1
Zhan La-sheng He Juan-mei Ye Yi-lin Zhao Hai-juan 《Chinese Astronomy and Astrophysics》2006,30(4):393-401
Using the wavelet technique, we analyzed the time series of solar radio fluxes at 2800 MHz as well as sunspot numbers and areas. The results are as follows: (1) These three data sets demonstrate that the most prominent period is 10.69 years and that all other periods are not obvious. (2) The wavelet power spectrum displays the changes of the power spectrum over the entire time-period range and shows the variations in the local power of a given period in a given time interval. Our analysis shows that periods shorter than one year are distinct only around solar activity maximum. (3) The time curves of the wavelet power at three periods (10.69 years, 5.11 years and 155.5 days) for the three times series are rather alike, with the same times of peaks and similar undulations. The shorter the period, the more frequent the fluctuations. 相似文献
12.
Using the method of Morlet wavelet transform, we analysed the sunspot relative numbers and obtained some meaningful results. The solar activity possesses the periods of 10.7a and 101a, and the period of 10.7a is very prominent. The variation of intensity of the solar activity exhibits certain stages. In 1950 there occurred abrupt changes of climate, and since then the solar activity has become more and more intense. It is predicted that it would be weaker for some time interval in the future. 相似文献
13.
本文讨论了子波变换用于信号突变检测的原理，用它分析了１７００－１９９３年间的太阳黑子数的年均值．精确地检测到了太阳活动的突变点，用相邻两个突变点的时间长度求得了不同尺度下太阳黑子变化的周期．结果表明：利用子波变换检测太阳黑子周期与传统方法相比具有独到之处． 相似文献
14.
我们对第12周至第22周的太阳黑子月平均面积数进行统计分析,并与相应的太阳黑子月平均数相比较,结果表明太阳黑子月平均面积数活动周与太阳黑子月平均数活动周有一定的关系。在多数情况下,太阳黑子出现最大值的时间与太阳黑子面积数出现最大值的时间上不一致;太阳黑子平滑月平均数活动周上升期与太阳黑子平滑月平均面积数上升期在大多数情况下不相同;太阳黑子平滑月平均数活动周平均效果的瓦德迈尔效应(Waldmeiereffect)一般要比太阳黑子平滑平均面积数的活动周明显;文中还对太阳黑子平滑月平均面积数活动周的特征进行了分析。 相似文献
15.
Wavelet Analysis of solar,solar wind and geomagnetic parameters 总被引：3，自引：0，他引：3
The sunspot number, solar wind plasma, interplanetary magnetic field, and geomagnetic activity index A
p have been analyzed using a wavelet technique to look for the presence of periods and the temporal evolution of these periods. The global wavelet spectra of these parameters, which provide information about the temporal average strength of quasi periods, exhibit the presence of a variety of prominent quasi periods around 16 years, 10.6 years, 9.6 years, 5.5 years, 1.3 years, 180 days, 154 days, 27 days, and 14 days. The wavelet spectra of sunspot number during 1873–2000, geomagnetic activity index A
p during 1932–2000, and solar wind velocity and interplanetary magnetic field during 1964–2000 indicate that their spectral power evolves with time. In general, the power of the oscillations with a period of less than one year evolves rapidly with the phase of the solar cycle with their peak values changing from one cycle to the next. The temporal evolution of wavelet power in R
z, v
sw, n, B
y, B
z, |B|, and A
p for each of the prominent quasi periods is studied in detail. 相似文献
16.
We have extended the proxy relationship between irradiance and microwaves by using the daily solar fluxes from Toyokawa Observatory at 1000, 2000, 3750 and 9400 MHz in addition to the Ottawa 2800 MHz flux for the years 1980–1989. It turns out that the flux at 1000 MHz is better correlated with irradiance than the flux at higher frequencies-an unexpected result. We have also found that the spectrum of the flux shows shape changes that are related to the number and type of active regions. Because of this the five-frequency spectral measurements of microwave flux allow one to separate the sunspot and coronal features, providing an improved proxy of solar variability. 相似文献
17.
Roy Soumya Prasad Amrita Panja Subhash Chandra Ghosh Koushik Patra Sankar Narayan 《Solar System Research》2019,53(3):224-232
The radio frequency emission at 10.7 cm (or 2800 MHz) wavelength (considered as solar flux density) out of different possible wavelengths is usually selected to identify periodicities because of its high correlation with solar extreme ultraviolet radiation as well as its complete and long observational record other than sunspot related indices. The solar radio flux at 10.7 cm wavelength plays a very valuable role for forecasting the space weather because it is originated from lower corona and chromospheres region of the Sun. Also, solar radio flux is a magnificent indicator of major solar activity. Here in the present work the solar radio flux data from 1965 to 2014 observed at the Domimion Radio Astrophysical Observatory in Penticton, British Columbiahas been processed using Date Compensated Discrete Fourier Transform (DCDFT) to identify predominant periods within the data along with their confidence levels. Also, the multi-taper method (MTM) for periodicity analysis is used to validate the observed periods. Present investigation exhibits multiperiodicity of the time series F10.7 solar radio flux data around 27, 57, 78, 127, 157, 4096 days etc. The observed periods are also compared with the periods of MgII Index data using same algorithm as MgII Index data has 99.9% correlation with F10.7 Solar Radio Flux data. It can be observed that the MgII index data exhibits similar periodicities with very high confidence levels.Present investigation also clearly indicates that the computed results are very much confining with the results obtained in different communication for the similar data of 10.7 cm Solar Radio Flux as well as for the other solar activities.
相似文献18.
K. J. Li Q. X. Li P. X. Gao J. Mu H. D. Chen T. W. Su 《Journal of Astrophysics and Astronomy》2007,28(2-3):147-156
Long-term variation in the distribution of the solar filaments observed at the Observatorie de Paris, Section de Meudon from
March 1919 to December 1989 is presented to compare with sunspot cycle and to study the periodicity in the filament activity,
namely the periods of the coronal activity with the Morlet wavelet used. It is inferred that the activity cycle of solar filaments
should have the same cycle length as sunspot cycle, but the cycle behavior of solar filaments is globally similar in profile
with, but different in detail from, that of sunspot cycles. The amplitude of solar magnetic activity should not keep in phase
with the complexity of solar magnetic activity. The possible periods in the filament activity are about 10.44 and 19.20 years.
The wavelet local power spectrum of the period 10.44 years is statistically significant during the whole consideration time.
The wavelet local power spectrum of the period 19.20 years is under the 95% confidence spectrum during the whole consideration
time, but over the mean red-noise spectrum of α = 0.72 before approximate Carrington rotation number 1500, and after that the filament activity does not statistically show
the period. Wavelet reconstruction indicates that the early data of the filament archive (in and before cycle 16) are more
noiseful than the later (in and after cycle 17). 相似文献
19.
An analysis has been carried out on the 32 years of 10 cm solar flux data, published by Covington, to test for evidence of the periodicities found by others using different techniques. Two features with periods of about 25 and 31 days appear to persist throughout the data, but there is no evidence for the 12.6 days periodicity claimed by Dicke and Goldenberg from solar ellipticity measurements, nor for the 12.07 day periodicity claimed by Knight et al. from an analysis of sunspot numbers. A 750 day periodicity is evident during 1970–75; this may correspond to the feature deduced by Sakurai from the sunspot numbers (and claimed to correlate with the neutrino flux); this feature can change in amplitude at other times. The other major feature has a period of about 1100 days, but disappears completely during 1970–75. The above periods are all synodic.On leave of absence at Sterrewacht, Leiden, The Netherlands during 1979/80. 相似文献
20.
1 ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｓｏｌａｒａｃｔｉｖｅｃｙｃｌｅｉｓｕｓｕａｌｌｙｄｅｓｃｒｉｂｅｄｗｉｔｈｔｈｅｒｅｌａｔｉｖｅｓｕｎｓｐｏｔｎｕｍｂｅｒｓ.Ａｎａｌｙｓｅｓｏｆｈｉｓ ｔｏｒｉｃａｌｄａｔａｏｎｔｈｅｒｅｌａｔｉｖｅｓｕｎｓｐｏｔｎｕｍｂｅｒｓｈａｖｅｒｅｖｅａｌｅｄａｗｅａｌｔｈｏｆｉｎｆｏｒｍａｔｉｏｎａｂｏｕｔｔｈｅｓｏｌａｒａｃｔｉｖｅｃｙｃｌｅ (ＨｏｎｇＱｉｎｆａｎｇ 1 990 ,1 994;ＺｈｏｎｇＳｈｕｈｕａ 1 991 ,1 995 ) .Ｔｈｅｓｏ ｃａｌｌｅｄ 1 1 ｙｅａｒｐｅ ｒｉｏ… 相似文献