共查询到19条相似文献，搜索用时 140 毫秒
1.
本文采用一种新的坐标系--耀斑-日球电流片坐标系,对1966-1982年间由耀斑-激波所引起的277个耀斑-地磁扰动事件进行了分析.初步结果是:1.耀斑-地磁扰动事件在该坐标系中相对日球电流片的随机分布呈高斯分布,极大值在电流片附近;2.当地球和耀斑位于日球电流片同侧时,地磁扰动事件频次远高于异侧;3.地磁扰动强弱在该坐标系中的分布,亦呈现了同侧高于异侧,且极大值多在日球电流片附近;4.耀斑-激波能流密度ρ2V23及其跃变量ρ2V23-ρ1V13在该坐标系中具有十分类似于相应磁扰水平的分布,其离散程度后者略大于前者. 根据本文的结果可以看出,对耀斑-地磁扰动研究来说,近太阳日球电流片的存在是一个重要的特征面,它对耀斑-地磁扰动的产生和强弱水平有重要影响,使太阳耀斑活动与地磁活动效应之间的对应关系变得复杂化了. 相似文献
2.
本文采用一种新的坐标系——耀斑-日球电流片坐标系,对1966—1982年间由耀斑-激波所引起的277个耀斑-地磁扰动事件进行了分析.初步结果是:1.耀斑-地磁扰动事件在该坐标系中相对日球电流片的随机分布呈高斯分布,极大值在电流片附近;2.当地球和耀斑位于日球电流片同侧时,地磁扰动事件频次远高于异侧;3.地磁扰动强弱在该坐标系中的分布,亦呈现了同侧高于异侧,且极大值多在日球电流片附近;4.耀斑-激波能流密度ρ_2V_2~3及其跃变量ρ_2V_2~3-ρ_1V_1~3在该坐标系中具有十分类似于相应磁扰水平的分布,其离散程度后者略大于前者. 根据本文的结果可以看出,对耀斑-地磁扰动研究来说,近太阳日球电流片的存在是一个重要的特征面,它对耀斑-地磁扰动的产生和强弱水平有重要影响,使太阳耀斑活动与地磁活动效应之间的对应关系变得复杂化了. 相似文献
3.
为探索地磁长期变化中地磁急变事件的识别方法，分析地磁急变的特征，本文基于多个地磁台站子夜均值数据，利用线性拟合方法计算了地磁场X，Y和Z三个分量的年变率，对近年来发生的地磁急变事件进行了识别和分析。结果显示:Y分量能对分析时段内已报道的地磁急变事件进行很好的识别，其中1999年的地磁急变事件，在我国区域内发生的时间可能为1998年，此外2017年可能存在一个新的地磁急变事件；Z分量年变率整体变化平缓，2001年和2013年前后发生两次显著的地磁年变率变化，并且分别早于2003年和2014年两次显著的地磁急变事件时间，这与下地幔的高电导率层对不同分量地磁信号从核幔边界传播至地表过程中的延迟作用有关；X分量年变率出现多次地磁急变事件特征，其变化与Dst指数年变率变化具有相关性，可利用其去除X分量年变率中存在的外部空间电流体系影响成分，更可靠地辅助Y分量对地磁急变事件进行识别。总体上，地磁子夜均值数据年变率的空间分布与基于第12代国际地磁参考场（IGRF12）模型计算的地磁数据年变率的空间分布所呈现的变化特征在总趋势上具有一致性，表明地磁台站子夜均值数据能够反映我国区域地球主磁场的变化特征，而分别由子夜均值数据和IGRF12模型计算的2003年Y分量年变率空间分布均存在的显著局部特征，可能与地磁急变事件的区域特征有关。 相似文献
4.
本文提出一种用于研究太阳瞬变扰动在日球空间传播的新坐标系--瞬变源-日球电流片坐标系,并运用该坐标系以瞬变源耀斑为例,分析研究了由地球近空飞船观测到的277个耀斑-激波事件,发现:1.引起行星际激波和地球物理事件的大耀斑（Hα≥2,持续时间>半小时）的频数在耀斑-日球电流片坐标系中呈高斯分布,极值在电流片附近,那种在日面坐标系中随日面纬度呈双峰形的分布看不到了;2.当地球观测者和耀斑位于日球电流片同侧时,耀斑事件频次明显高于它们分处不同侧时的情形;3.激波参数（速度、磁场、密度和温度）呈现了同侧高于异侧,强激波多在同侧观测到;4.激波沿日球电流片方向的传播具有一定优势.上述结果表明,日球电流片的存在对瞬变扰动,如耀斑-激波在日球空间,特别是近太阳的传播可能具有重要影响. 相似文献
5.
用中国地磁台站的资料,研究了Sq逐日变化的形态学特征,用理论模型计算了磁层环电流、部分环电流、场向电流、磁尾电流、Chapman-Ferraro电流的地磁效应.在消除了这些磁层电流体系的影响之后,得到了电离层潮汐风发电机电流产生的磁场Sq变化.对1973年的资料研究表明,Sq发电机电流的逐日变化主要表现在强度上,即使在磁扰期间,也可以分离出形态稳定的Sq变化.由此提出了一种新的地磁指数--Sq指数,用来描述Sq发电机电流强度的逐日变化. 相似文献
6.
为了解极光电集流在sawtooth事件期间的响应情形,本文利用北半球高纬地磁台站的磁场数据,建立了以球元基本电流系反演法求得大尺度电离层水平等效电流系分布的方法,以此研究了2000年9月30日同步轨道LANL卫星观测到的sawtooth事件期间极光电集流的变化.本文将sawtooth注入事件后极区电离层夜侧西向电集流增长的特征,与中低纬地基磁场北向分量正弯扰的特征做比较分析.两者的观测结果都表明在本sawtooth注入事件期间有电流楔的形成,且电流楔约有11 h磁地方时(MLT)的宽度.此外,中低纬磁弯扰达到最大扰动值的时间一般比高纬电集流达到最大扰动值的时间长,说明影响中低纬磁弯扰变化的电流源较丰富. 相似文献
7.
选取易县地震台YRY-4型分量式钻孔应变仪2012—2020年观测数据,进行Venedikov调和分析,并对2015—2020年四分量数据S1、S2、S3、S4进行自洽检验,发现应变观测数据连续性、可靠性较高。选取该台2018—2019年钻孔应变原始数据S1、S2、S3、S4,利用面应变S1 + S3、S2 + S4相关系数,分析河北省3次ML≥4.0地震前数据异常变化,并利用剪应变S1 - S3、S2 - S4的大小,分析受抽水干扰的NE分量主应力方位角,判断干扰源方位,结果发现：①面应变与剪应变在地震发生前均会出现异常变化,且剪应变异常变化幅度较大,应与震中相对于观测井的位置有关;②对于受抽水干扰的钻孔应变NE分量,利用剪应变固体潮数据推算主应力方位角,可得干扰源在钻孔应变观测室NW80.96°方位,与实际位置存在一定偏差。 相似文献
8.
本文讨论了行星际磁场B2分量变化时内磁层和中低纬度电离层的响应.指出B2变化引起的磁层大尺度对流电场的变化在一定条件下有可能透入内磁层,并沿磁力线映射到中低纬度电离层,在那里产生电场和电流体系,从而使Sq电流体系发生畸变,并在地面磁场中反映出来.数值计算表明,当△B2<0时,Sq电流体系的焦点向东和向高纬移动,地面磁场会观测到数伽马的变化.这就为中低纬地磁观测诊断磁层和太阳风状态提供了一种可能性.此外,本文还用上述物理过程解释了赤道地区一些高空物理现象,如B2倒转时电离层漂移速度的变化,赤道磁场异常以及赤道q型偶现E层的消失等等. 相似文献
9.
磁暴的发生与环电流的变化密切相关.除了对称环电流外，部分环电流在磁暴的发展过程中也起到了重要的作用，同时部分环电流通过场向电流与极区电离层中的电流形成回路.本文应用INTERMAGNET地磁台网北半球中低纬区域地磁台站数据，对不同强度4个磁暴事件主相和恢复相期间部分环电流和场向电流的磁地方时分布进行了分析和讨论.对于每一个磁暴事件，在低纬地区（地磁纬度约0°—40°N）选用地磁经度上大致均匀的8个台站，通过坐标转换计算平行于磁偶极轴的地磁场水平分量H来分析磁暴期间环电流所引起的磁场扰动；在低纬地区8个台站的基础上增加中纬地区（地磁纬度约40°N—60°N）地磁经度上大致均匀的6个台站，计算地磁坐标系下地磁场东西分量Y来分析磁暴期间场向电流在中低纬地区引起的磁场扰动.结果表明，磁暴主相期间的部分环电流主要作用于磁地方时昏侧和夜侧扇区，并且主相和恢复相期间部分环电流引起的磁场变化随着磁暴级别的增大而增大；磁暴主相期间向下的场向电流多出现在夜侧至晨侧扇区，向上的场向电流多出现在昏侧至午后扇区，且中纬地区向下和向上场向电流的展布范围明显大于低纬地区；恢复相期间弱、中磁暴事件的场向电流呈现与部分环电流相同的减弱趋势，而强、大磁暴事件在恢复相末期场向电流引起的磁场变化明显不同于恢复相的其他时刻，这可能与高纬较强的亚暴活动有关. 相似文献
10.
本文研究了1938-1958年间,太阳γ及βγ黑子磁場区的3級与3~+級大耀斑的地磁效应。用相关及迴归分析法,計算了太阳赤緯、日軸方位角及耀斑的日面經緯度等因素对于磁扰的彭响。根据分析結果,繪出了日面地磁扰动等值图。利用水手2号飞船上量譜仪測出的太阳风速度和相应的地磁A_p指数,算出了相关关系,并用此和上述日面地磁扰动等值图配合,推算了在耀斑发生以后,太阳风的径向分量沿地球軌道的分布。参考文內各相应的曲线,可以約略估計出耀斑发生后地磁A_p指数的大小。 相似文献
11.
《Journal of Atmospheric and Solar》2008,70(15):1971-1984
We performed a comparative study of geomagnetic variations, which are associated with sudden ionospheric disturbances (SIDs) caused by great X-class solar flares on July 14, 2000 (Bastille flare) and on October 28, 2003 (Halloween flare). Intense fluxes of solar X-rays and EUV radiation as well as solar energetic particles (SEP) were considered as sources of abundant ionization of the ionosphere and upper atmosphere. Flare-initiated SIDs are revealed as transient geomagnetic variations, which are generated by enhanced electric currents flowing mainly in the bottom-side ionosphere. Those so-called solar flare effects (SFEs) were studied by using of geomagnetic data from INTERMAGNET worldwide network of ground-based magnetometers. In subsolar region the SFE is mainly controlled by the flare X-rays and/or EUV radiation. We found that in the Halloween flare the contribution of X-rays was comparable with the EUV, but in the Bastille flare the EUV flux was dominant. The ionization at high latitudes is generated by the SEP, which energy flux is comparable and even exceeds the solar electromagnetic radiation in that region. It was shown that in the Halloween event the pattern of SFE is formed by a two-vortex current system, which is similar to the quiet day Sq current system. However, during the Bastille flare, the pattern of induced currents is quite different: the northern vortex shifts westward and southern vortex shifts eastward such that the electroject is substantially tilted relative to the geomagnetic equator. From numerical estimations we found that at middle latitudes the SEP-initiated geomagnetic effect becomes comparable with the effects of solar electromagnetic radiation. It was also shown that the SEP contribute to the SFE in the nightside hemisphere. The revealed features of the SEP impact to the ionosphere were found in a good agreement with the theory of energetic particle penetration to the bottom-side magnetosphere. 相似文献
12.
M. I. Tyasto N. G. Ptitsyna I. S. Veselovsky O. S. Yakovchouk 《Geomagnetism and Aeronomy》2009,49(2):153-162
A retrospective analysis of the Russian magnetic observations of the Carrington event that occurred on September 2–3, 1859, has been performed. The conclusion has been made that this event was caused by the series of three recurrent eruptive solar flares during ～40 h. The characteristics of the geomagnetic crochet, related to a considerable flux of the ionizing electromagnetic radiation during this flare, have been studied. The value and direction of a magnetic field disturbance, registered during the maximum of the geomagnetic storm of September 2, unambiguously indicate that all Russian stations were in the auroral oval zone, which was strongly expanded southward from its average position. The disturbance dependence on the station longitude—the absence of magnetometer pinning in Nerchinsk—is interpreted as the possible manifestation of a strong asymmetry in the effective contour of the current system, which was connected to the heliosphere and covered the disturbed magnetosphere and ionosphere during the short period that lasted only 1–3 h. 相似文献
13.
本文选取了INTERMAGNET地磁台网2001年到2012年的地磁数据,对其进行世界时(UT)到地方时(LT)的转换后利用自然正交分量法(NOC)从所选资料中提取出太阳静日变化Sq成分,再通过球谐分析方法建立模型分离内、外源Sq成分,逐日反演出内、外源Sq等效电流体系,并得到外源Sq等效电流体系南北电流涡中心电流强度.本文将外源Sq等效电流体系南北电流涡中心电流强度与同一时期的Dst指数进行了对比分析,研究表明它们之间具有同步变化的规律,且北半球电流涡中心电流强度在磁暴发生时的异常现象远高于南半球.对F10.7cm太阳射电流量与外源Sq等效电流体系南、北半球电流涡中心电流强度的长短周期分析发现,Sq等效电流表现出明显的11年周期特点,与太阳活动周期一致.外源南、北半球电流涡中心电流强度和F10.7cm年均值的相关系数分别达到了0.93和0.90,说明太阳活动是导致外源Sq电流体系变化的最直接也最主要的因素,这可能与电离层电导率受控于太阳的电磁辐射相关. 相似文献
14.
N. A. Barkhatov V. N. Obridko S. E. Revunov S. D. Snegirev D. V. Shadrukov O. A. Sheiner 《Geomagnetism and Aeronomy》2016,56(2):249-255
We compare long-period pulsations of the horizontal component of the geomagnetic field at intervals that precede extreme solar flares. To this end, we use the wavelet–skeleton technique to process the geomagnetic field disturbances recorded at magnetic stations over a wide geographical range. The synchronization times of wavelet–skeleton spectral distributions of long-period pulsations of geomagnetic oscillations over all magnetic stations are shown as normalized histograms. A few days before an intense solar flare, the histograms show extremes. This means that these extremes can be regarded as flare precursors. The same technique is used to analyze the parameters of near-Earth space. The histograms obtained in this case are free of the aforementioned extrema and, therefore, cannot point to an upcoming flare. The goal of this study is to construct a correlation–spectral method for the short-term prediction of solar flare activity. 相似文献
15.
Based on statistical data and a detailed analysis of geomagnetic response to the hard electromagnetic radiation of the X17
solar flare of September 7, 2005, we considered spatial features of current systems producing the geomagnetic solar flare
effect (SFE). During flares accompanied by intensive X-rays and gamma rays, SFEs are shown to be observed globally, including
the night hemisphere and high latitudes. Cause-effect relations of phenomena under consideration are discussed. 相似文献
16.
A weak active region (NOAA 11158) appeared on the solar disk near the eastern limb. This region increased rapidly and, having reached the magnetic flux higher than 1022 Mx, produced an X-class flare. Only weak field variations at individual points were observed during the flare. An analysis of data with a resolution of 45 s did not indicate any characteristic features in the photospheric field dynamics during the flare. When the flux became higher than 3 × 1022 Mx, active region NOAA 10720 produced six X-class flares. The field remained quiet during these flares. An increase in the magnetic flux above ～1022 Mx is a necessary, but not sufficient, condition for the appearance of powerful flares. Simple active regions do not produce flares. A flare originates only when the field distribution in an active region is complex and lines of polarity inversion have a complex shape. Singular lines of the magnetic field can exist only above such active regions. The current sheets, in the magnetic field of which the solar flare energy is accumulated, originate in the vicinity of these lines. 相似文献
17.
在本文里, 我们对ＣＭＥ 和太阳耀斑现象的各种相互关系进行了讨论希望本文的内容能够引起天文、空间物理和地球物理等人员的兴趣, 促进ＣＭＥ的综合研究 相似文献
18.
地磁扰动是空间天气中的重要现象,对地基技术系统具有重要的影响.准确预报地磁扰动可以有效避免重大灾害发生.本文基于Weimer电势和磁势模型发展了高纬地区地磁扰动的模拟方法,并与地面台站观测数据进行了比较.地表磁场扰动主要受电离层电流系统的影响,利用Weimer模式计算出电离层等效电流分布后,基于毕奥-萨伐尔定律推导了地磁扰动三分量与电流的关系,最终计算出地磁扰动量.模型的输入参数为太阳风速度、太阳风密度、行星际磁场和磁偶极倾角.模型计算结果与不同纬度和经度的地磁台站观测结果对比表明本文的计算方法能有效地模拟地磁暴期间地磁扰动特征.本文结果对今后发展高纬地区地磁场预报模型奠定了重要基础. 相似文献
19.
R. G. Rastogi D. R. K. Rao S. Alex B. M. Pathan T. S. Sastry 《Annales Geophysicae》1997,15(10):1301-1308
Changes in the three components of geomagnetic field are reported at the chain of ten geomagnetic observatories in India during an intense solar crochet that occurred at 1311 h 75° EMT on 15 June 1991 and the subsequent sudden commencement (SSC) of geomagnetic storm at 1518h on 17 June 1991. The solar flare effects (SFE) registered on the magnetograms appear to be an augmentation of the ionospheric current system existing at the start time of the flare. An equatorial enhancement in AH due to SFE is observed to be similar in nature to the latitudinal variation of SQ (H) at low latitude. AF registered the largest effect at 3.6° dip latitude at the fringe region of the electrojet. AZ had positive amplitudes at the equatorial stations and negative at stations north of Hyderabad. The SSC amplitude in the H component is fairly constant with latitude, whereas the Z component again showed larger positive excursions at stations within the electrojet belt. These results are discussed in terms of possible currents of internal and external origin. The changes in the Y field strongly support the idea that meridional current at an equatorial electrojet station flows in the ionospheric dynamo, E.Presently at: School of Physics, University of New South Wales, Sydney, Australia 相似文献