共查询到20条相似文献，搜索用时 177 毫秒
1.
A limb, two-ribbon H flare on June 4, 1991, associated with a white-light flare and followed by an emission spray and post-flare loops, is studied. A region of rapidly enhanced brightness at the bottom of the H ribbon above the white-light flare is revealed. The energy released by the white-light flare at eff = 4100 is estimated to be about 1.5 × 1028 erg s–1. 相似文献
2.
W. T. Thompson W. M. Neupert S. D. Jordan H. Jones R. J. Thomas B. Schmieder 《Solar physics》1993,147(1):29-46
This paper describes the results of comparing SERTS-3 images obtained in the transition region line of Heii 304 with chromospheric Hei 10830 absorption, with strong coronal lines of Mgix 368 , Fexv 284 and 417 , and Fexvi 335 and 31 , with H, with Caii 8542 , and with magnetograms in Fei 8688H. All of the images are illustrated, and the image reconstruction techniques used are described and evaluated. The high correlation of the Heii 304 and Hei 10830 images, originally found by Harvey and Sheeley (1977), is confirmed and is put on a quantitative basis. We find that the supergranulation network has greater contrast, and that filaments appear darker, in 10830 than in 304 . In active regions, the 304 line follows more closely the behavior of H and Caii 8542 than the 10830 line. 相似文献
3.
Large field H observations of the Milky Way between Carina and Aquila were made through a narrow interference filter 15 wide. Characteristic large-scale features of the observed region are extended emission areas in Carina, Norma-Scorpius and Scutum-Sagittarius and some weak isolated nebulosities near the Coal Sac, Centauri and Normae. H photographs, a chart mapping the emission, and a list of identified emission regions are given. 相似文献
4.
Theoretical Ca X electron temperature sensitive emission line ratios, derived using electron excitation rates interpolated from accurateR-matrix calculations, are presented forR
1 =I(419.74 )/I(574.02 ,),R
2 =I(411.65 )/I(574.02 ),R
3 =I(419.74 )/I(557.75 ), andR
4 =I(411.65 )/I(557.75 ). A comparison of these with observational data for three solar flares, obtained by the Naval Research Laboratory's S082A slitless spectrograph on boardSkylab, reveals good agreement between theory and observation forR
1 andR
3 in one event, which provides limited support for the accuracy of the atomic data adopted in the analysis. However, in the other flares the observed values ofR
1 –R
4 are much larger than the theoretical high-temperature limits, which is probably due to blending of the 419.74 line with Civ 419.71 , and 411.65 with possibly Ciii 411.70 . 相似文献
5.
A list of solar spectral lines in the wavelength 4300–6700 exhibiting large Stokes V amplitudes in observed spectra of active region plages and the quiet network is presented.Visiting astronomer at National Solar Observatory, operated by the Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation. 相似文献
6.
Hongqi Zhang 《Solar physics》1993,146(1):75-92
A series of H chromospheric magnetograms was obtained at various wavelengths near the line center with the vector video magnetograph at Huairou Solar Observing Station as a diagnostic of chromospheric magnetic structures. The two-dimensional distribution of the circular polarization light of the H line with its blended lines at various wavelength in active regions was obtained, which consists of the analyses of Stokes' profileV of this line. Due to the disturbance of the photospheric blended line Fei 4860.98 for the measurement of the chromospheric magnetic field, a reversal in the chromospheric magnetograms relative to the photospheric ones occurs in the sunspot umbrae. But in the quiet, plage regions, even penumbrae, the influence of the photospheric blended Fei 4860.98 line is not obvious. As regards the observation of the H chromospheric magnetograms, we can select the working wavelength between -0.20 and -0.24 from the line core of H to avoid the wavelengths of the photospheric blended lines in the wing of H.After the spectral analysis of chromospheric magnetograms, we conclude that the distribution of the chromospheric magnetic field is similar to the photospheric field, especially in the umbrae of the sunspots. The chromospheric magnetic field is the result of the extension of the photospheric field. 相似文献
7.
Theoretical electron-temperature-sensitive Mgix emission line ratios are presented forR
I =I(443.96 )/I(368.06 ),R
2 =I(439.17 )/I(368.06 ),R
3 =I(443.37 )/I(368.06 ),R
4 =I(441.22 )/I(368.06 ), andR
5 =I(448.28 )/I(368.06 ). A comparison of these with observational data for a solar active region, obtained during a rocket flight by the Solar EUV Rocket Telescope and Spectrograph (SERTS), reveals excellent agreement between theory and observation forR
1 throughR
4, with discrepancies that average only 9%. This provides experimental support for the accuracy of the atomic data adopted in the line ratio calculations, and also resolves discrepancies found previously when the theoretical results were compared with solar data from the S082A instrument on boardSkylab. However in the case ofR
5, the theoretical and observed ratios differ by almost a factor of 2. This may be due to the measured intensity of the 448.28 line being seriously affected by instrumental effects, as it lies very close to the long wavelength edge of the SERTS spectral coverage (235.46–448.76 ). 相似文献
8.
The results of spectrophotometric observations of CH Cyg in an active phase and during emergence from it are given: the spectral energy distribution in the 3225-7500 range with 23 resolution, the absolute monochromatic illuminances at eight selected wavelengths in the 3225-8015 , and the emission fluxes in the H and H lines. The features of the energy distribution in the stellar spectrum and the observed forms of variability, different between the short-wavelength and red parts of the spectrum, are determined by the instability of both of the system's components. In the active phase, CH Cyg's emission in the observed spectral range can be represented as the total emission from a cool M6 III giant and a hot hydrogen gas with a temperature T
e
= 10,000-15,000 K. In the low-brightness state, the star's energy distribution fully corresponds to that of a cool giant, the spectrum of which varies from M6 III to M7 III. The photometric variability of the cool component in the 8015 range is 0
m
.3-0
m
.4. An increase in the brightness of the cool giant preceded a bright outburst of the hot component. 相似文献
9.
( , 1977; , 1977). , , , . . 相似文献
10.
Data on solar emission variations in the extreme ultraviolet range <1300 (EUV-range) performed on board the Prognoz satellites and the Phobos spacecraft by the thermoluminescent method are presented. Flux variations from the 11-years cycle are factors of 2–2.5, and that by the 27-days cycle do not exceed 30%. 相似文献
11.
А. М. Крымский Л. С. Марочник П. Д. НаселБский Н. В. Пелихов 《Astrophysics and Space Science》1978,55(2):299-324
=qr, I II (Marochniket al., 1975 a, b), . , II; , . , , ye , . . t
g. 相似文献
12.
A time series of K3 spectroheliograms taken at the Coimbra Observatory exhibits an erupting loop on the east limb on July 9, 1982 in active region NOAA 3804. The Goddard SMM Hard X-Ray Burst Spectrometer (HXRBS) observations taken during this period reveal a hard X-ray flare occurring just before the loop eruption is observed, and SMS-GOES soft X-ray observations reveal a strong long-duration event (LDE) following the impulsive phase of the flare. A Solwind coronagram exhibits a powerful coronal mass ejection (CME) associated with the erupting loop. H flare and prominence observations as well as centimeter and decimeter radio observations of the event are also reviewed. A large, north–south-oriented quiescent prominence reported within the upper part of the CME expansion region may play a role in the eruption as well. The spatial and temporal correlations among these observations are examined in the light of two different current models for prominence eruption and CME activation: (1) The CME is triggered by the observed hard X-ray impulsive flare. (2) The CME is not triggered by a flare, and the observed soft X-ray flare is an LDE due to reconnection within the CME bubble. It is concluded that this event is probably of a mixed type that combines characteristics of models (1) and (2). The July 9 event is then compared to three other energetic CME and flare eruptions associated with the same active-region complex, all occurring in the period July 9 through September 4, 1982. It is noted that these four energetic events coincide with the final evolutionary phase of a long-lasting active-region complex, which is discussed in a companion paper (Bumba, Garcia, and Jordan, 1997). The paper concludes by addressing the solar flare myth controversy in the light of this work. 相似文献
13.
D3 and H pictures of prominences were obtained with a 21-in. Lyot coronograph and a Fabry-Perot etalon used as a narrow band filter. The monochromatic images of quiescent, quasiquiescent and loop-prominences were studied. The comparison of the isophotes of quiescent and quasi-quiescent prominences in D3 with those in H shows the similarity of the prominence structure at both wavelength, although there is a strong tendency for an increase in the intensity ratio D3/H in the upper region of prominences. It seems that it is due to lower temperature in the upper regions of prominences. Probably, the relaxation processes establishing ionization equilibrium play some role. Measurements of the knot intensities of the loop-prominence show strong variations of the intensity ratio D3/H (more than one order of magnitude). 相似文献
14.
We have analyzed the H filtergrams and vector magnetograms of the active region NOAA 7070, in which a 3B/X3.3 flare occurred on February 27, 1992. The average area per sunspot of this active region was in declining phase at the time of the flare. The vector magnetograms indicate that the magnetic field was non-potential at the flaring site. Besides non-potentiality, the longitudinal field gradient was found to be the highest at the region showing initial H brightening. Further, in H filtergrams no appreciable change in the morphology of the filament tracing the magnetic neutral line was noticed in the post-flare stage. Also, the photospheric vector magnetograms show considerable shear in post-flare magnetic field of the active region. In this paper we present the observations and discuss the possible mechanism responsible for the 3B/X3.3 flare. 相似文献
15.
Marie K. McCabe 《Solar physics》1985,98(1):127-140
The H observations of a limb flare, which were associated with exceptional gamma-ray and hard X-ray emission, are presented and discussed. The good spatial and temporal resolution of the H data allow us to investigate the detailed structure of the elevated flare loops and the intensity variations of the loops, footpoints and surrounding chromosphere during each phase of the flare event. A delay time of 12 s was found between at least one of the hard X-ray (28–485 keV) peaks and corresponding H intensity maximum at a loop footpoint. A comparison is made between this event and another well-observed limb flare with many similar characteristics to seek evidence for the large difference in their levels of energy release. 相似文献
16.
. ]Qi . , r=r. . , . H>2G, — , . , . . .
The exact solutions for the equilibrium of rotating gaseous disk with poloidal magnetic field are obtained. The stability of the disk with respect to uniform expansion and contraction is investigated by means of the variational principle. It is shown that if the equilibrium is determined by gravitational and magnetic forces only, the disk is in neutral equilibrium with respect to perturbations of the form r=r. The instability to short-waves perturbations is studied by the quasi-classical method. The analysis shows that if the magnetic field isH>2G, where is the surface density, then these perturbations are stabilized. The configurations of the electrical field induced by the rotation of magnetized disk are found. In conclusion, the questions of the evolution of the disk are discussed in connection with the quasar model when pulsar-like radiation is taken into account.相似文献
17.
F. P. Keenan E. S. Conlon D. A. Bowden B. N. Dwivedi K. G. Widing 《Solar physics》1994,149(1):137-142
Theoretical electron-density-sensitive emission line ratios in B-like AIix are presented forR =I(385.01 )/I(392.42 ). A comparison of these with high spectral resolution solar flare data, obtained with the S082A slitless spectrograph on boardSkylab, reveals agreement between theory and observation for those spectra that were observed during the later stages of the flares. These results provide experimental support for the accuracy of the line-ratio calculations, and also resolves discrepancies found previously when the theoretical results were compared with solar observations from the S-055 instrument on boardSkylab. However, the agreement between theory and observation for a spectrum obtained during the early stages of a flare is very poor, which probably indicates that the 392.42 line is blended with a transition arising from a species formed at a very high electron temperature. 相似文献
18.
. . .
, 相似文献
Transfer of resonance radiation in infinite medium is considered as a process of random walks of photons. Close relation is shown to exist between the problems of transfer of line radiation and the stable distributions of the probability theory. This relation is used as a basis of a new method for the investigation of the asymptotic properties of the radiation field far from the sources.
, 相似文献
19.
Solar flares,microflares, nanoflares,and coronal heating 总被引：2，自引：0，他引：2
H. S. Hudson 《Solar physics》1991,133(2):357-369
Solar flare occurrence follows a power-law distribution against total flare energy W: dN/dW W
– with an index 1.8 as determined by several studies. This implies (a) that microflares must have a different, steeper distribution if they are energetically significant, and (b) there must be a high-energy cutoff of the observed distribution. We identify the distinct soft distribution needed for coronal heating, if such a distribution exists, with Parker's nanoflares.This paper considers a microflare to be a member of the normal X-ray burst population, with comparable physical parameters except for a smaller total energy. 相似文献
20.
We study the active region NOAA 6718 and the development of a (2N, M3.6) flare in radio and H. Due to our knowledge of the magnetic field structure in the active region we are able to associate the different radio flare burst components with the stages in the H flare evolution. A discussion of the data in terms of chromospheric flare kernel heating reveals that in the present case the observed flare-related radio burst continuum switch-off is caused by the penetration of hot, ablated gas into the coronal radio source. 相似文献