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1.
本文对Ｏｓｈｅｒｏｖｉｃｈ的黑子返回磁通量模型作了适当的修改，使用黑子中心作为边界条件，用五种观测结果，导出了理论模型所需的五个主要参量，用半经验方法求得了黑子静力学模型的磁场、压力和温度等物理量．将此模型应用于一个中等大小的圆形对称黑子，可得到一个特解，结果发现我们的模型既能满足黑子的磁性质，同时又能满足合理的热力学量分布． 相似文献
2.
R. P. Kane 《Solar physics》2007,246(2):471-485
Many methods of predictions of sunspot maximum number use data before or at the preceding sunspot minimum to correlate with
the following sunspot maximum of the same cycle, which occurs a few years later. Kane and Trivedi (Solar Phys. 68, 135, 1980) found that correlations of R
z(max) (the maximum in the 12-month running means of sunspot number R
z) with R
z(min) (the minimum in the 12-month running means of sunspot number R
z) in the solar latitude belt 20° – 40°, particularly in the southern hemisphere, exceeded 0.6 and was still higher (0.86)
for the narrower belt > 30° S. Recently, Javaraiah (Mon. Not. Roy. Astron. Soc.
377, L34, 2007) studied the relationship of sunspot areas at different solar latitudes and reported correlations 0.95 – 0.97 between minima and maxima of sunspot areas at low latitudes
and sunspot maxima of the next cycle, and predictions could be made with an antecedence of more than 11 years. For the present
study, we selected another parameter, namely, SGN, the sunspot group number (irrespective of their areas) and found that SGN(min) during a sunspot minimum year at latitudes > 30° S had a correlation
+0.78±0.11 with the sunspot number R
z(max) of the same cycle. Also, the SGN during a sunspot minimum year in the latitude belt (10° – 30° N) had a correlation +0.87±0.07 with the
sunspot number R
z(max) of the next cycle. We obtain an appropriate regression equation, from which our prediction for the coming cycle 24 is R
z(max )=129.7±16.3. 相似文献
3.
A Fabry-Perot interferometer is being used for two-dimensional spectropolarimetric measurements. We demonstrate the suitability of the setup for the measurement of the magnetic field and present some preliminary results from first observations. 相似文献
4.
《New Astronomy》2015
Analysis of long-term solar data from different observatories is required to compare and confirm the various level of solar activity in depth. In this paper, we study the north–south asymmetry of monthly mean sunspot area distribution during the cycle-23 and rising phase of cycle-24 using the data from Kodaikanal Observatory (KO), Michelson Doppler Imager (MDI) and Solar Optical Observing Network (SOON). Our analysis confirmed the double peak behavior of solar cycle-23 and the dominance of southern hemisphere in all the sunspot area data obtained from three different resources. The analysis also showed that there is a 5–6 months time delay in the activity levels of two hemispheres. Furthermore, the wavelet analysis carried on the same data sets showed several known periodicities (e.g., 170–180 days, 2.1 year) in the north–south difference of sunspot area data. The temporal occurrence of these periods is also the same in all the three data sets. These results could help in understanding the underlying mechanism of north–south asymmetry of solar activity. 相似文献
5.
P. Sriramachandran S. P. Bagare N. Rajamanickam K. Balachandrakumar 《Solar physics》2008,252(2):267-281
High-resolution Fourier Transform Spectrometer sunspot umbral spectra of the National Solar Observatory/National Optical Astronomy
Observatory at Kitt Peak were used to detect rotational lines from 19 electronic transition bands of the molecules LaO, ScO
and VO, in the wavenumber range of 11 775 to 20 600 cm−1. The presence of lines from the following transitions is confirmed: A
2
Π
r1/2 – X
2
Σ
+(0, 0; 0, 1), A
2
Π
r3/2 – X
2
Σ
+(1, 0), B
2
Σ
+ – X
2
Σ
+(0, 0; 0, 1; 1, 0) and C
2
Π
r1/2 – A′2Δ
r3/2(0, 0; 1, 1) of LaO; A
2
Π
r3/2 – X
2
Σ
+(0, 0), A
2
Π
r1/2 – X
2
Σ
+(0, 0) and B
2
Σ
+ – X
2
Σ
+(0, 0) of ScO; and C
4
Σ
− – X
4
Σ
−(0, 1; 1, 0; 0, 2) and (2, 0) of VO. However, the presence of A
2
Π
r3/2 – X
2
Σ
+(0, 0) and C
2
Π
r3/2 – A′2Δ
r5/2(0, 0; 1, 1) of LaO and C
4
Σ
− – X
4
Σ
−(0, 0) of VO are found to be doubtful because the lines are very weak, and detections are difficult owing to heavy blending
by strong rotational lines of other molecules. Equivalent widths are measured for well-resolved lines and, thereby, the effective
rotational temperatures are estimated for the systems for which the presence is confirmed. 相似文献
6.
V. E. Abramov-Maksimov G. F. Vyalshin G. B. Gelfreikh V. I. Shatilov 《Solar physics》1996,164(1-2):333-343
In the present paper we present the results of measurement of magnetic fields in some sunspots at different heights in the solar atmosphere, based on simultaneous optical and radio measurements. The optical measurements were made by traditional photographic spectral observations of Zeeman splitting in a number of spectral lines originating at different heights in the solar photosphere and chromosphere. Radio observations of the spectra and polarization of the sunspot - associated sources were made in the wavelength range of 2–4 cm using large reflector-type radio telescope RATAN-600. The magnetic field penetrating the hot regions of the solar atmosphere were found from the shortest wavelength of generation of thermal cyclotron emission (presumably in the third harmonic of electron gyrofrequency). For all the eight cases under consideration we have found that magnetic field first drops with height, increases from the photosphere to lower chromosphere, and then decreases again as we proceed to higher chromosphere and chromosphere-corona transition region. Radio measurements were found to be well correlated with optical measurements of magnetic fields for the same sunspot. An alternative interpretation implies that different lines used for magnetic field measurements refer to different locations on the solar surface. If this is the case, then the inversion in vertical gradients of magnetic fields may not exist above the sunspots. Possible sources of systematic and random errors are also discussed. 相似文献
7.
8.
We study the pattern and behavior of a rotating sunspot in Active Region 10930. The rotational angular speed has been extracted
from the apparent motions of the sunspot determined by applying a new optical technique – called non-linear affine velocity
estimator (NAVE) – to high-resolution G-band images taken by the Solar Optical Telescope (SOT) onboard the Hinode satellite. The structure and dynamics of coronal loops in this active region have been examined using the images obtained
by the X-Ray Telescope (XRT) and the spectral data taken by the Extreme-ultraviolet Imaging Spectrometer (EIS), both also onboard Hinode. Our results are summarized as follows: i) The small sunspot of positive polarity rotated counterclockwise about its center by 540° during the period of five days.
ii) Its angular velocity varied with the azimuth angle as well as the radial distance, being affected by the asymmetric shape
of the umbra. iii) The angular velocity increased up to 8° h−1 until 13 December as the sunspot grew, and then decreased rapidly down to 3° h−1 on the next day as the sunspot decayed. iv) The coronal loops that connected the two sunspots became sigmoidal in shape. v) The coronal emissions from the regions around the rotating sunspot were blueshifted, which may indicate the expansion of
the coronal loops. Our results suggest that the rotation of the sunspot may be closely related to the dynamic development
of emerging twisted magnetic fields. 相似文献
9.
Ernesto R. Rodríguez Flores Rafael Gmez Díaz Ramn E. Rodríguez Taboada 《Journal of Atmospheric and Solar》2005,67(17-18):1728
Based on high-resolution (0.3 arcsec) observations, we studied the behavior of solar granulation in the neighborhood of a sunspot. The bright granules’ spatial distribution and the granules’ surface density as a function of distance from the center of the sunspot umbra were determined.Bright granules distribute delimiting cells of dimensions in the mesogranular scale. The mean diameter of these cells does not show significant variation with the variation of the magnetic field of the sunspot. The granules’ surface density does not show significant variation with distance to the sunspot umbra. Both results point to a very weak, if any, influence of the sunspot magnetic field at distances greater than 20 arcsec. 相似文献
10.
In recent high-resolution observations of complex active regions, long-lasting and well-defined regions of strong flows were
identified in major flares and associated with bright kernels of visible, near-infrared, and X-ray radiation. These flows,
which occurred in the proximity of the magnetic neutral line, significantly contributed to the generation of magnetic shear.
Signatures of these shear flows are strongly curved penumbral filaments, which are almost tangential to sunspot umbrae rather
than exhibiting the typical radial filamentary structure. Solar active region NOAA 10756 was a moderately complex β
δ sunspot group, which provided an opportunity to extend previous studies of such shear flows to quieter settings. We conclude
that shear flows are a common phenomenon in complex active regions and δ spots. However, they are not necessarily a prerequisite condition for flaring. Indeed, in the present observations, the photospheric
shear flows along the magnetic neutral line are not related to any change of the local magnetic shear. We present high-resolution
observations of NOAA 10756 obtained with the 65-cm vacuum reflector at Big Bear Solar Observatory (BBSO). Time series of speckle-reconstructed
white-light images and two-dimensional spectroscopic data were combined to study the temporal evolution of the three-dimensional
vector flow field in the β
δ sunspot group. An hour-long data set of consistent high quality was obtained, which had a cadence of better than 30 seconds
and subarcsecond spatial resolution. 相似文献