共查询到20条相似文献，搜索用时 78 毫秒
1.
七十年代以来的空间和地面观测表明,太阳耀斑是太阳大气中最剧烈的动力学过程。耀斑动力学的研究已成为当今太阳物理研究中重要的前沿课题之一.本文概要地介绍近年来在耀斑动力学过程的观测和理论方面的重要进展以及耀斑大气动力学的光谱诊断方法,并讨论了今后在观测和理论两方面的努力方向,为我国在即将到来的太阳22周峰年中的耀斑动力学研究提供参考. 相似文献
2.
太阳耀斑研究进展和展望 总被引：3，自引：0，他引：3
简要回顾了近年来对太阳耀斑研究在某些方面所取得的进展，这些领域空间和地面观测，耀斑光谱研究，耀斑的动力学模型和MHD数值模拟等，并对耀斑研究的前景作一简短的展望。 相似文献
3.
4.
云南天文台是参加日地系统整体行为研究计划的单位之一,有四套太阳光学观测设备参加日地大事件的联合观测。它们是:13cm折射望远镜、18cm耀斑巡视望远镜、26cm高分辨太阳光球色球望远镜和多波段太阳光谱仪。13cm折射望远望和18cm耀斑巡视镜分别进行黑子描绘、照相和耀斑巡视的常规观测。它们所得的资料供云南天文台《太阳活动月报》、《中国太阳物理资料》发表。耀斑资料还供SGD发表。黑子和耀斑的常规观测为太阳活动预报提供及时的信息和基础。 26cm高分辨真空太阳光球色球望远镜用于太阳活动区现象特别是耀斑现象的精细结构研究。在耀斑观测中常使用H_a的±0.5A,±1.0A对人观测,所得的耀斑偏带照片清楚显示耀斑的亮点和亮块相对于黑子的位置,在耀斑研究中十分有用。 多波段太阳光谱仪的供光定天镜口径40cm,成像镜30cm,太阳象有152.2mm和418.5mm两个交替使用,色散1A/mm,10个波段分别为H_a、D_(1,2,3),H_δ、HeⅡ、H_β、H_γ、H,K、H_(9-13)和H_(13-∞)。利用计算机控制45°转象镜精确地快速扫描太阳象并控制10个波段的同时照相,这样可以快速地记录活动区中每一点的多波段光谱轮廓,进而测定各种物理量、为研究活动区物理场的时空演化提供重要手段。 相似文献
5.
6.
我们用紫台多波段太阳光谱仪进行耀斑光谱观测。这架仪器能在Hα、D、M_g、H_β、H_γ、H、H_δ——K、H_θ——H_(12)和H_(13)——H∞等九个波段基本上同时拍摄耀斑光谱。太阳像直径为11.2厘米,二级光谱的实测分辨率约10万,线色散度约为1毫米/埃。在这次峰年期间,从1980年2月至1981年5月,我们一共拍到16套耀斑光谱底片。我们已开始用这些资料来研究,(1)耀斑的能量传输机制,(2)耀斑的热动平衡偏离,(3)地面与空间观测资料的配合,(4)形态研究,并已开始归算处理这些资料。 相似文献
7.
多云模型’’是处理太阳活动体光谱不对称轮廓的有效方法,本文给出了该方法的一个具体应用实例,利用云南天文台二维多波段太阳光谱仪观测的１９８９年８月１７日耀斑环Ｈβ波段光谱资料,得到了该耀斑环的视向速度场． 相似文献
8.
太阳空间观测揭示出太阳的高能电子、高能质子发射以及γ射线爆发。证实了有关的太阳射电辐射理论、揭示出太阳耀斑中的核反应。日冕物质抛射和耀斑等离子体云的空间观测揭示出它们之间的区别和联系, 认识到耀斑的热区和冷区。太阳和日球磁场观测发展了磁流体动力学理论 相似文献
9.
本文综述了近年来太阳和恒星白光耀斑研究的最新进展。文中着重讨论了两类白光耀斑的光谱特征，白光耀斑的大气模型，以及白光耀斑大气的加热机制等问题，并对恒星白光耀斑同太阳白光耀斑作了某些比较。 相似文献
10.
南京大学太阳塔CCD成像光谱观测系统和初步观测结果 总被引：1，自引：0，他引：1
本文介绍南京大学太阳塔的ＣＣＤ成像光谱观测系统的结构，工作方式，给出了该系统的一些性能测试结果，作为应用该系统的实例，文中给出了根据该系统观测的二维光谱资料，经处理得到的一个Ｈａ耀斑在线心和不同偏带处单色像的变化过程，该耀斑的亮度场轮廓图和速度场轮廓图。 相似文献
11.
《中国天文和天体物理学报》2014,(9)
正Research in Astronomy and Astrophysics publishes original research papers and reviews 011 all liranchcs of astronoiriy and astrophysics.Reviews arc by invitation only.Important new results that require rapid publication can be submitted as a Letter(Letters must be restricted in length 相似文献
12.
Laura Schaefer 《Icarus》2004,169(1):216-241
We modified the MAGMA chemical equilibrium code developed by Fegley and Cameron (1987, Earth Planet. Sci. Lett. 82, 207-222) and used it to model vaporization of high temperature silicate lavas on Io. The MAGMA code computes chemical equilibria in a melt, between melt and its equilibrium vapor, and in the gas phase. The good agreement of MAGMA code results with experimental data and with other computer codes is demonstrated. The temperature-dependent pressure and composition of vapor in equilibrium with lava is calculated from 1700 to 2400 K for 109 different silicate lavas in the ONaKFeSiMgCaAlTi system. Results for five lavas (tholeiitic basalt, alkali basalt, Barberton komatiite, dunite, and a molten type B1 Ca, Al-rich inclusion) are discussed in detail. The effects of continuous fractional vaporization on chemistry of these lavas and their equilibrium vapor are presented. The predicted abundances (relative to Na) of K, Fe, Si, Al, Ca, and Ti in the vapor equilibrated with lavas at 1900 K are lower than published upper limits for Io's atmosphere (which do not include Mg). We predict evaporative loss of alkalis, Fe, and Si during volcanic eruptions. Sodium is more volatile than K, and the Na/K ratio in the gas is decreased by fractional vaporization. This process can match Io's atmospheric Na/K ratio of 10±3 reported by Brown (2001, Icarus 151, 190-195). Silicon monoxide is an abundant species in the vapor above lavas. Spectroscopic searches are recommended for SiO at IR and mm wavelengths. Reactions of metallic vapors with S- and Cl-bearing volcanic gases may form other unusual gases including MgCl2, MgS, MgCl, FeCl2, FeS, FeCl, and SiS. 相似文献
13.
14.
《中国天文和天体物理学报》2014,(10)
正Research in Astronomy and Astrophysics publishes original research papers and reviews on all branches of astronomy and astrophysics.Reviews are by invitation only.Important new results that require rapid publication can be submitted as a Letter(Letters must be restricted in length to 6 printed pages).Authors who submit a paper are expected to be able to certify that the paper is original work, 相似文献
15.
Laura Schaefer 《Icarus》2005,173(2):454-468
We use chemical equilibrium calculations to model the speciation of alkalis and halogens in volcanic gases emitted on Io. The calculations cover wide temperature (500-2000 K) and pressure (10−6 to 10+1 bars) ranges, which overlap the nominal conditions at Pele (T=1760 K, P=0.01 bars). About 230 compounds of 11 elements (O, S, Li, Na, K, Rb, Cs, F, Cl, Br, I) are considered. The elemental abundances for O, S, Na, K, and Cl are based upon observations. CI chondritic elemental abundances relative to sulfur are used for the other alkalis and halogens (as yet unobserved on Io). We predict the major alkali species in Pele-like volcanic gases and the percentage distribution of each alkali are LiCl (73%), LiF (27%); NaCl (81%), Na (16%), NaF (3%); KCl (91%), K (5%), KF (4%); RbCl (93%), Rb (4%), RbF (3%); CsCl (92%), CsF (6%), Cs (2%). Likewise the major halogen species and the percentage distribution of each halogen are NaF (88%), KF (10%), LiF (2%); NaCl (89%), KCl (11%); NaBr (89%), KBr (10%), Br (1%); NaI (61%), I (30%), KI (9%). We predict the major halogen condensates and their condensation temperatures at P=0.01 bar are NaF (1115 K), LiF (970 K); NaCl (1050 K), KCl (950 K); KBr (750 K), RbBr (730 K), CsBr (645 K); and solid I2 (200 K). We also model disequilibrium chemistry of the alkalis and halogens in the volcanic plume. Based on this work and our prior modeling for Na, K, and Cl in a volcanic plume, we predict the major loss processes for the alkali halide gases are photolysis and/or condensation onto grains. Their estimated photochemical lifetimes range from a few minutes for alkali iodides to a few hours for alkali fluorides. Condensation is apparently the only loss process for elemental iodine. On the basis of elemental abundances and photochemical lifetimes, we recommend searching for gaseous KCl, NaF, LiF, LiCl, RbF, RbCl, CsF, and CsCl around volcanic vents during eruptions. Based on abundance considerations and observations of brown dwarfs we also recommend a search of Io's extended atmosphere and the Io plasma torus for neutral and ionized Li, Cs, Rb, and F. 相似文献
16.
17.
Yehouda Enzel Rivka Amit Uri Dayan Onn Crouvi Ron Kahana Baruch Ziv David Sharon 《Global and Planetary Change》2008,60(3-4):165-192
Modern-day synoptic-scale eastern Mediterranean climatology provides a useful context to synthesize the diverse late Pleistocene (60–12 ka) paleohydrologic and paleoenvironmental indicators of past climatic conditions in the Levant and the deserts to its south and east. We first critically evaluate, extract, and summarize paleoenvironmental and paleohydrologic records. Then, we propose a framework of eastern Mediterranean atmospheric circulation features interacting with the morphology and location of the southeast Mediterranean coast. Together they strongly control the spatial distribution of rainfall and wind pattern. This cyclone–physiography interaction enforces the observed rainfall patterns by hampering rainfall generation south and southeast of the latitude of the north Sinai coast, currently at 31°15′.The proposed framework explains the much-increased rains in Lebanon and northern Israel and Jordan as deduced from pollen, rise and maintenance of Lake Lisan, and speleothem formation in areas currently arid and semiarid. The proposed framework also accounts for the southward and eastward transition into semiarid, arid, and hyperarid deserts as expressed in thick loess accumulation at the deserts' margins, dune migration from west to east in the Sinai and the western Negev, and the formation of hyperarid (< 80 mm yr− 1) gypsic–salic soils in the southern Negev and Sinai. Our climatic synthesis explains the hyperarid condition in the southern Negev, located only 200–250 km south of the much-increased rains in the north, probably reflecting a steeper rainfall gradient than the present-day gradient from the wetter Levant into its bordering southern and eastern deserts.At present, the rainiest winter seasons in Lebanon and northern and central Israel are associated with more frequent (+ 20%), deeper Cyprus Lows traversing the eastern Mediterranean at approximately the latitude of southern Turkey. Even these wettest years in northern Israel do not yield above average annual rainfall amounts in the hyperarid southern Negev. This region is mainly influenced by the Active Red Sea Troughs that produce only localized rains. The eastern Mediterranean Cyprus Lows also produce more dust storms and transport higher amounts of suspended dust to the loess area than any other atmospheric pattern. Concurrent rainfall and dust are essential to the late Pleistocene formation of the elongated thick loess zone along the desert northern margin. Even with existing dust storms, the lack of rain and very sparse vegetation account for the absence of late Pleistocene loess sequences from the southern Negev and the formation of hyperarid soils.When the north Sinai coast shifted 30–70 km northwest due to last glacial global sea level lowering, the newly exposed coastal areas supplied the sand and dust to these active eastern Mediterranean cyclones. This enforced the latitude of the northern boundary of the loess zone to be directly due east of the LGM shoreline. This shift of coast to the northwest inhibited rainfall in the southern Levant deserts and maintained their hyperaridity. Concurrently, frequent deep eastern Mediterranean Cyprus Lows were funneled along the northern Mediterranean increasing (probably doubling) the rains in central and northern Israel, Lebanon, southwestern Syria and northern Jordan. These storms and rains formed lakes, forests, and speleothems only a short distance north of the deserts in the southern Levant. 相似文献
18.
Philippe Stee 《Astrophysics and Space Science》2003,286(1-2):225-236
Interferometry in the visible provides milliarcsecond spatial resolution and thus has been used for studying the circumstellar
environment of active hot stars. In this paper I will illustrate how the visibility modulus and phase can be used to better
constrain the physics of Be disks through results from the VLA, the MkII and the GI2T interferometers. I will insist on the
importance and the potential of coupling high angular resolution with high spectral resolution to the study of Be shells.
Finally I will present a possible study of the circumstellar disk of Be stars using the VLTI.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
19.
The central compact object for some gamma-ray bursts (GRBs) may be a strongly magnetized millisecond pulsar. It can inject energy to the outer shock of the GRB by through the magnetic dipole radiation, and therefore causes the shallow decay of the early afterglow. Recently, from a large number of GRB X-ray afterglows observed by Swift/XRT(X-ray telescope), it is revealed that many of them exhibit the shallow decay about 102∼104 s after the burst prompt emission. We have fitted the X-ray afterglow light curves of 11 GRBs by using the energy injection model of a magnetar with the rotation period in the millisecond order of magnitude. The obtained result shows the validity and universality of the magnetar energy injection model in explaining the shallow decay of afterglows, and simultaneously provides some constraints on the magnetic field strength and rotation period of the central magnetar. 相似文献
20.
We consider the kinetics of a rarefied rotating planetary atmosphere. The spatial distributions of the atmospheric-gas density and mean angular velocity were determined by analyzing the exact solution of the two-dimensional kinetic equation. We show that the angular velocity of the gas at some distance from the planet could be higher than that in the initial layer starting from which the atmosphere is rarefied. Our model calculations elucidate the superrotation mechanism under consideration. 相似文献