共查询到20条相似文献,搜索用时 31 毫秒
1.
There is increasing evidence that various manifestations of solar activity are non-axisymmetric and mainly occur in two preferred longitude ranges, so called active longitudes. We have earlier analyzed the longitudinal occurrence of solar X-ray flares observed by GOES satellites using a specially developed dynamic, differentially rotating coordinate system. In this frame, the longitude distribution shows two persistent preferred longitudes separated by about 180 degrees whose strength alternates in time according to the so called flip-flop phenomenon. Here we make the first global statistical analysis to find the best fitting values for parameters describing the differential rotation of active longitudes of X-ray flares. We find that the new analysis greatly improves the earlier values for the rotation parameters, making them consistent between the three different classes of X-ray flares. The improved parameters also yield a systematically higher level of non-axisymmetry for the longitudinal distribution, thus increasing the statistical significance of the existence of active longitudes. Accordingly, a significant amount of X-ray flares of different classes are produced by the same two active longitudes. We also find a significant difference between the rotation rates in the two solar hemispheres, with active longitudes rotating faster than the Carrington rate in the northern hemisphere and slower than the Carrington rate in the southern hemisphere. 相似文献
2.
K. G. Ivanov 《Geomagnetism and Aeronomy》2010,50(6):695-710
A more detailed scenario of one stage (August–November 2004) of the quasibiennial MHD process “Origination ... and dissipation
of the four-sector structure of the solar magnetic field” during the decline phase of cycle 23 has been constructed. It has
been indicated that the following working hypothesis on the propagation of an MHD disturbance westward (in the direction of
solar rotation) and eastward (toward the zone of active longitudes) with the displacement of the large-scale open solar magnetic
field (LOSMF) from this zone can be constructed based on LOSMF model representations and data on sunspot formation, flares,
active filaments, and coronal ejections as well as on the estimated contribution of sporadic energy release to the flare luminosity
and kinetic energy of ejections: (1) The “explosion” of the LOSMF singularity and the formation in the explosion zone of an
anemone active region (AR), which produced the satellite sunspot formation that continued west and east of the “anemone,”
represented a powerful and energy-intensive source of MHD processes at this stage. (2) This resulted in the origination of
two “governing” large-scale MHD processes, which regulated various usual manifestations of solar activity: the fast LOSMF
along the neutral line in the solar atmosphere, strongly affecting the zone of active longitudes, and the slow LOSMF in the
outer layers of the convection zone. The fronts of these processes were identified by powerful (about 1031 erg) coronal ejections. (3) The collision of a wave reflected from the zone of active longitudes with the eastern front of
the hydromagnetic impulse of the convection zone resulted in an increase in LOSMF magnetic fluxes, origination of an active
sector boundary in the zone of active longitudes, shear-convergent motions, and generation and destabilization of the flare-productive
AR 10696 responsible for the heliospheric storm of November 3–10, 2004. 相似文献
3.
K. G. Ivanov 《Geomagnetism and Aeronomy》2009,49(5):557-565
The phenomena of superconcentration of the large-scale field photospheric sources in the main zone of active longitudes, blocking of regular differential rotation by these sources, and origination of the four-sector structure of the solar magnetic field during the decline phase of cycle 23 have been considered in more detail and taking into account the polar correction. It has been indicated that superconcentration was formed due to the penetration of photospheric sources into the zone from the western surroundings of this zone and owing to the generation of the large-scale field in the zone itself. The dynamics of a blocking-induced complex MHD disturbance with reflected from the zone and reconnecting photospheric sources of negative and positive polarity, respectively, and the transformation of the bisector structure into the four-sector one have been considered. It has been indicated that the dynamics of this MHD disturbance was responsible for that of associated solar activity: the generation of sunspot groups, appearance of flares, and, finally, origination of a powerful heliospheric storm and the solar-terrestrial extrastorm of July 22–27, 2004. 相似文献
4.
It is shown that “active longitudes” for the sunspots of old and new cycles manifest themselves approximately in the same longitudinal intervals and remain for several 11-year cycles. To be more accurate, they vanish in some cycles but then appear again at the same longitudinal intervals in the other cycles. The entire period is characterized by a total of four active longitudes. The old-cycle sunspots observed at low equatorial latitudes in the Northern and Southern Hemispheres are characterized by a shift by ≈180°, which indicates antipodality of the active longitudes in the Northern and Southern Hemispheres. In the case of highlatitude sunspots (new-cycle sunspots), the best correlation is observed for the shift of ≈90°. There is supposedly a dependence of the rotation speed of active longitudes on the secular cycle. 相似文献
5.
作者在前一篇文章里分析每月五天国际磁扰日在太阳自轉周里的頻率分布,得到下述两个結論: 1.国际地磁干扰日在太阳自轉周里确实存在着一个不变的頻率分布,地磁場发生干扰的可能性,在頻率高的日序里約为在頻率低的日序里的二倍。 2.太阳的活动性,在太阳經圈上的分布是不均勻的,有些部分活动性強,有些部分活动性弱。 相似文献
6.
Using the tabulations of spread-F data from ionosonde recordings the diurnal, annual and sunspot-cycle variations of this spread-F occurrence have been investigated for the equatorial station, Huancayo. Both Rz max and Rz min periods have been considered. The analyses suggest that some explanation of these variations can be made by involving two regimes, which have been called Regime A and Regime B. The Regime A is present throughout the night but this distribution is more obvious after midnight. This is because in the post-sunset period Regime B, which is associated with significant height rises, is dominant. The Regime A is the same as for similar distributions in mid-latitudes and is inversely related to sunspot activity. It maximizes in December solstice months. The Regime B is directly related to sunspot activity and maximizes in equinoctial months. Changes associated with the upper atmosphere neutral particle density have been found to be important, particularly for Regime A where an inverse relationship exists. The Regime A Rz min annual distributions reported here for Huancayo have been compared with similar distributions at other longitudes and latitudes. 相似文献
7.
Based on an analysis of a large array of meteorological data, we have shown that surface air temperatures differ significantly
in years of sunspot maxima and minima for different months and latitudes and longitudes of observation points. This difference
is the greatest at high latitudes of 60–83°; it is equal to +2.07 ± 0.28°C in February in the longitudinal range of 170 ±
190° and −1.41 ± 0.29°C in November in the longitude range of 150 ± 170°. 相似文献
8.
Intersector disbalance of the large-scale open solar magnetic field fluxes,active and passive boundaries,and solar-terrestrial extrastorms 总被引:1,自引:1,他引:0
The dynamics (from rotation to rotation) of the absolute values of the large-scale open solar magnetic field fluxes in the four-sector field structure has been considered for the first time, using CRs 2032–2035 in July–October 2005 as examples. An important role of the ratio of the fluxes at the eastern and western sector boundaries (Φ E /Φ W ) is confirmed. As in the cases of the two-sector structure, Φ E /Φ W > 1 is typical of active rigidly corotating boundaries with intense sunspot formation, flares, and interplanetary and geomagnetic disturbances. A remarkable property of the considered structure was the presence of a rapidly increasing flux in an initially narrow sector and the flux interaction with a stable rigidly corotating sector in the zone of the main active longitudes, which caused an unexpectedly strong geoeffective long-range action of flares near the corresponding active boundary. 相似文献
9.
K. G. Ivanov 《Geomagnetism and Aeronomy》2010,50(3):285-297
The dynamics of the large-scale open field and solar activity at the second stage of the MHD process, including the origination
and disappearance of the four-sector structure during the decline phase of cycle 23 (the stage when the blocking field is
displaced from the main zone of active longitudes), has been considered. Extremely fast changes in the scales of one of new
sectors (from an extremely small sector (“singularity”) to a usual sector that originated after the uniform expansion (“explosion”)
of singularity with a “kick” into the zone of active longitudes, westward motion of the MHD disturbance front in the direction
of solar rotation, and formation of an active quasi-rigidly corotating sector boundary responsible for the heliospheric storm
of November 2004) have been detected in the field dynamics. It has been indicated that a very powerful group of sunspots AR
10656 (which disappeared after the explosion) with an area of up to 1540 ppmh (part per million hemisphere), a considerable
deficit of the external energy release, and zero geoeffectiveness in spite of the closeness to the Earth helioprojection existed
within singularity. It has been assumed that the energy escaped from this group with effort owing to the interaction between
coronal ejections and narrow sector walls (singularity), and a considerable part of the energy was released in the outer layers
of the convective zone, as a result of which singularity exploded and this explosion was accompanied by the above effects
in the large-scale field and solar activity. 相似文献
10.
制约和影响中国大陆地震活动大形势的动力因素研究 总被引:5,自引:0,他引:5
从地球动力学角度,研究制约和影响我国大陆地震活动的兴衰起伏的内在原因,揭示我国大陆地震活动期(300年)、幕(20年左右)、段(几年)实际是由于太阳黑子活动、地球自转速率变化、全球强震活动水平在不同阶段迭加和组合的结果。 相似文献
11.
A. G. Tlatov 《Geomagnetism and Aeronomy》2013,53(8):953-956
Relative variations in the number of sunspots and sunspot groups in activity cycles have been analyzed based on data from the Kislovodsk Mountain Astronomical Station and international indices. The following regularities have been established: (1) The relative fraction of small sunspots decreases linearly and that of large sunspots increase with increasing activity cycle amplitude. (2) The variation in the average number of sunspots in one group has a trend, and this number decreased from ~12 in cycle 19 to ~7.5 in cycle 24. (3) The ratio of the sunspot index (Ri) to the sunspot group number index (G gr) varies with a period of about 100 years. (4) An analysis of the sunspot group number index (G gr) from 1610 indicates that the Gnevyshev-Ohl rule reverses at the minimums of secular activity cycles. (5) Ratio of the total area to area of Ssp/Sum nuclei has long-term variation with a period approximately 8 cycles. Minimum ratio falls on 16–17 cycles of activity. (6) It has been indicated that the magnetic field intensity and sunspot area in the current cycle are related to the amplitude of the next activity cycle. 相似文献
12.
The phenomenon of long-period sunspot oscillations with periods from several tens to a thousand minutes is studied using data on the magnetic field strength and sunspot coordinates obtained based on the SOHO MDI data. It has been indicated that oscillations of the sunspot magnetic field strength are related to relative and absolute horizontal oscillation modes, as a result of which certain limitations are imposed on the interpretation of the phenomenon. 相似文献
13.
14.
The MHD nature of the origination, dynamics, geoeffectiveness, and disappearance of the four-sector structure of the solar magnetic field during the cycle 23 decline phase has been established. A prolonged ordered MHD process including the chain of the interrelated phenomena (unknown before this study), which begin and end in one of the main zones of active longitudes and are responsible for the above nature of the four-sector structure, has been detected as a result of the simulation of the large-scale open solar magnetic field and an analysis of the dynamics of this field fluxes. These phenomena are as follows: the extreme concentration of the photospheric field sources of the same sign in the zone of active longitudes; blocking of regular differential rotation by these sources; origination of a nonstationary MHD disturbance in the form of a four-sector structure, traveling in the direction of solar rotation at a nearly Alfvén velocity; upset of blocking, displacement of blocking sources from the zone, and their shearing motion relative to a traveling MHD disturbance; deceleration and dissipation of a four-sector MHD disturbance; and reconstruction of a bisector structure. The interactions during this process, which lasted from May 2004 to December 2005, were accompanied by the generation of an ordered succession of heliospheric and solar-terrestrial disturbances including the series of nine extrastorms that were observed from July 2004 to September 2005 and were the last storms in the finished cycle 23 of solar activity. 相似文献
15.
S. A. Yazev 《Geomagnetism and Aeronomy》2009,49(7):871-878
Discrete location of large flares near zero Carrington longitude results in artificial breaks within physically related flare
clusters. This effect is eliminated by using the data presentation algorithm, which results in the conclusion that drifting
zones of intensified sunspot formation (concentrated cores of activity complexes) and energetic flare generation exist in
either hemisphere. The indicated L zone is hypothetically related to a non-asymmetric relic solar magnetic field or to the
regions where large-scale convective cells, extending to the convective zone bottom, originate. 相似文献
16.
17.
The effect of the ponderomotive force on the background plasma modification near magnetic holes, which form at the dayside magnetospheric boundary under the action of the solar wind, has been studied. It was shown that this effect results in a substantial increase in a nonlinear plasma density disturbance. The dependence of the ponderomotive force on the magnetospheric parameters (the magnetic longitude, distance from the Earth’s surface, ratio of the wave frequency to the proton gyrofrequency, and ionospheric ion cyclotron wave amplitude) has been studied. Nonlinear plasma density disturbances will be maximal in the region of magnetic holes, which are located in the dayside magnetosphere at λ ~ 0°?30° geomagnetic longitudes (λ = 0° corresponds to noon), where the effect of the solar wind pressure is maximal. A similar effect is also observed in the dependence of a nonlinear plasma density disturbance on other magnetospheric parameters. 相似文献
18.
JianChang Zheng ZhaoGuo Huang Zhi Wu XiQing Hao JiaLun Ji BaiQi Ning LianHuan Hu XiuKuan Zhao GuoZhu Li 《中国科学:地球科学(英文版)》2016,59(8):1692-1699
Equatorial spread-F (ESF) backscatter plumes are often observed in radar range-time-intensity (RTI) maps at low latitude. Except case studies, few statistical investigations on the onset locations of scintillation-producing ESF plumes at given sites have been conducted. In this study, a statistical analysis is carried out on onset locations of ESF backscatter plumes observed at a low-latitude location Sanya (18.4°N, 109.6°E; dip lat 12.8°N) during equinoctial months of 2013. By employing a tracing method to locate backscatter plumes, we estimate the onset longitudes of periodic plumes obtained from the Sanya VHF radar five-beam steering measurements. The results show that the inter-plume distances (in longitude) are mostly confined within 200–600 km, and the ESF plumes producing ionospheric scintillations over Sanya are almost exclusively generated at the longitudes of 94°–110°E. The results indicate the necessity to monitor ESF plume initial generation in the longitude region of 94°–110°E to better understand the day-to-day variability in the occurrence of ionospheric scintillations over Sanya. 相似文献
19.
It is well known that the 630-nm nightglow emission intensity in midlatitudes increases by more than a factor of 2 during a sunspot maximum. It has been assumed that the phenomenon is caused by variations in solar UV radiation during a solar cycle (Fishkova, 1983). We present the results of photometric measurements of the nightglow 630.0 nm emission intensity at a latitude of 63° E and longitude of 130° E (Yakutsk) in 1990–2007. The dependence of the 630-nm emission intensity on solar activity on magnetically quiet days in the 22nd and 23rd solar cycles is shown. The close relationship between the 630-nm nightglow intensity and the intensity of extreme UV (EUV) with a correlation coefficient of 0.8–0.9 in 1997–2007 is ascertained from the SOHO/SEM data. The dominance of solar EUV in the excitation of nightglow 630-nm emission has thus been experimentally proved. 相似文献
20.
Gui-Qing Zhang 《地震学报(英文版)》1998,11(4):495-500
The relations between sunspot numbers and earthquakes (M≧6), solar 10.7 cm radio flux and earthquakes, solar proton events and earthquakes have been analyzed in this paper. It has
been found that: (1) Earthquakes occur frequently around the minimum years of solar activity. Generally, the earthquake activities
are relatively less during the peak value years of solar activity, some say, around the period when magnetic polarity in the
solar polar regions is reversed. (2) the earthquake frequency in the minimum period of solar activity is closely related to
the maximum annual means of sunspot numbers, the maximum annual means of solar 10.7 cm radio flux and solar proton events
of a whole solar cycle, and the relation between earthquake and solar proton events is closer than others. (3) As judged by
above interrelationship, the period from 1995 to 1997 will be the years while earthquake activities are frequent. In the paper,
the simple physical discussion has been carried out.
These results supported the exploration and studies of some researchers to a certain extent.
This work is supported by Foundation of the Chinese Academy of Sciences (major item). 相似文献