Some mechanical analogies of magnetodynamic oscillations in a homogeneous medium     

Karel Prikner 《Studia Geophysica et Geodaetica》1970,14(3):339-344

Zusammenfassung Es wird auf die Analogien hingewiesen zwischen dem einfachsten Fall der Resonanz einer ebenen MD-Welle im Modell homogener Schicht der Erdmagnetosph?re und horizontaler Schwingung einer homogenen elastischen S?ule mit einem befestigten Ende. Es wird qualitativ die Analogie zwischen dem Anprall eines materiellen K?rpers an eine elastische S?ule mit einem befestigten Ende und dem Stoss der Front von Sonnenwind auf die Erdmagnetosph?re angedeutet. Diese Ann?herung erm?glicht die Illustration einiger Züge von Pulsationen, welche pl?tzliche Ver?nderungen in magnetischem Felde der Erde (Impulse si, ssc u. ?.) begleiten und deren Beschreibung auf Grund pr?ziser Theorie der Verbreitung von MD-Wellen sehr schwierig ist.

---

---

Address: Boční II, Praha 4-Spořilov.  相似文献   

Mean Earth'S Equipotential Surface From Topex/Poseidon Altimetry     

Milan Burša  Jan Kouba  Karel Raděj  Scott A. True  Viliam Vatrt  Marie Vojtíšková 《Studia Geophysica et Geodaetica》1998,42(4):459-466

The geopotential value of W ₀ = (62 636 855.611 ± 0.008) m ² s ^–2 which specifies the equipotential surface fitting the mean ocean surface best, was obtained from four years (1993 - 1996) of TOPEX/POSEIDON altimeter data (AVISO, 1995). The altimeter calibration error limits the actual accuracy of W ₀ to about (0.2 - 0.5) m ² s ^–2 (2 - 5) cm. The same accuracy limits also apply to the corresponding semimajor axis of the mean Earth's level ellipsoid a = 6 378 136.72 m (mean tide system), a = 6 378 136.62 m (zero tide system), a = 6 378 136.59 m (tide-free). The variations in the yearly mean values of the geopotential did not exceed ±0.025 m ² s ^–2 (±2.5 mm).  相似文献   

Changes in the reflectivity of the midlatitude ionosphere with respect to the ULF (Pc1) signal     

Karel Prikner  Vladimír Vagner  Reviewer M. Hvoždara 《Studia Geophysica et Geodaetica》1988,32(1):84-100

Summary The method of numerical modelling of ionospheric filtration of the Fourier components of a signal from the frequency range of Pc1 micropulsations is employed in the spectral analysis (frequency f, angle of incidence ) of the relative characteristic of the amplitude and energy reflectivity of the ionospheric layer with respect to ordinary Alfvén modes incident in the meridional plane. The results are presented for four different models characterizing the midlatitude day- and night-time ionosphere under low and high solar activity. The results indicate the specificity of filtration of ordinary Alfvén waves. It is proved that the lower region of the modelled ionosphere, as part of the midlatitude ionospheric wave guide (in particular the F2 layer), behaves like an Alfvén resonator in the given spectral range.

---

m¶rt; u ¶rt;uau u umauu -mau uaa u amm ¶rt;uanaa unau 1 n¶rtum nma aau (amma f, a¶rt;u ) mum anum¶rt; u mu maamu u ¶rt; ¶rt; a, a¶rt;au a u u¶rt;ua nmu. mam n¶rt;aam ¶rt; m a ¶rt; ¶rt;um m ¶rt; u u nu u u nu amumu. aam nuum umauu a. naa, m ua am ¶rt;ua u (a am F2-u ¶rt;um ¶rt;a) ¶rt;m nma ¶rt;uana a am a.

  相似文献   

Single- and inter-station transfer functions for non-synchronous geomagnetic arrays-II. the results of the field data analysis     

Karel Pěč  Jana Pěčová  Oldřich Praus  Reviewer M. Hvoždara 《Studia Geophysica et Geodaetica》1988,32(4):368-391

Summary The theory of methods of computing single- and inter-station transfer functions in both the spectral and time domains was developed in paper[1]. Both approaches are applied to the variation data recorded at field stations along two non-simultaneous profiles traversing the eastern margin of the Bohemian Massif, where a zone of anomalous induction seems to mark an important geological boundary of formations with different histories of development. The results of both analyses are found to coincide within reasonable bounds of 20–30% in the principal induction characteristics.

---

u m¶rt; ama ¶rt;-u -mau n¶rt;am u nma u am a ua am[1]. am nua m am a n¶rt;¶rt;a nu ¶rt; aaua ¶rt;aaum auau aumua a n mau ¶rt; u nu, nau m au aua,¶rt; aa a aa u¶rt;uu. a, u¶rt;u, mamau a¶rt;a ¶rt; ¶rt; ¶rt;uuau au umuu aumu. mam aau nma u am auam a 20–30% ¶rt; u¶rt;u naam.

  相似文献   

Explanation of the internal air pressure effect on the worden gravity meter dial constant     

Karel Diviš  Vladimír Tobyáš  Bohumil Chán  Reviewer Z. Šimon 《Studia Geophysica et Geodaetica》1989,33(2):206-209

Summary A model, explaining the effect of air pressure changes in the space of the measuring system on the fine dial counter constant of the Worden and similar gravity meters, is presented. It is based on the changes of the bellows volume with compensating the gravity changes. It is shown that the resetting the gravity meter in the whole range has practically no influence on the fine dial counter constant.

---

u¶rt;a ¶rt;, na m uu ¶rt;au ¶rt;a nmam uum um a nm a umaauma ¶rt; u nuaum. ¶rt; aa a uu a ua umu uma nu nauu uu u mmu. aa, m nma ¶rt;uanaa um namuu um a uu nm a uma.

  相似文献   

Normal density earth models   总被引：1，自引：0，他引：1  

Zedeněk Martinec  Karel Pěč  Reviewer M. Burša 《Studia Geophysica et Geodaetica》1986,30(2):124-147

Summary Models of the Earth's density, close to thePREM model, have been derived, they reproduce the external normal gravitational field of the Earth and its dynamic flattening, and are referred to as normal density models. The Earth's surface is approximated by an ellipsoid of the order of the flattening, or of its square. Of the group of normal models sgtisfying the solution of the inverse problem, the normal density modelHME2 is recommended. The spherically symmetric density modelPREM, which was corrected in the course of solving the inverse problem, thus creating the modifiedPREM-E2 model, was used as the a priori information.

---

¶rt; ¶rt;u an¶rt;u nmmu uu ¶rt;uPREM (m. a. a ¶rt;u nmmu), aumau n m u¶rt;mu na¶rt;am auaumau n u. m u annuum am unu¶rt; au. uau amu a ¶rt; mam H==0.003 273 994. ma ¶rt; a ¶rt; ¶rt;m ¶rt;HME2. am anu u a ¶rt; nmmu a unaa ¶rt; a¶rt;ua umua ¶rt;PREM. ¶rt;aam ¶rt;uuau m ¶rt;u n¶rt; aauPREM-E2.

  相似文献   

Peculiarities of electron precipitation in morning sector of auroral zone during geomagnetic storm     

Yu. V. Gotselyuk  M. S. Kazaryan  S. N. Kuznetsov  Karel Kudela  Ivan Kimák  Reviewer S. Fischer 《Studia Geophysica et Geodaetica》1986,30(1):79-86

Summary The analysis of electron (E _e >30keV) and proton (E _p >150keV) precipitating fluxes measured on low altitude satellite Intercosmos-17 during the geomagnetic storm December 2, 1977 is presented. Particularly, the gap in electron precipitation on morning side at L=5÷6 is analyzed and discussed in terms of strong cyclotron diffusion.  相似文献   

Matrix approach to the solution of free toroidal elastic oscillations of the earth     

Zdeněk Martinec  Karel Pěč  Reviewer Z. Martinů 《Studia Geophysica et Geodaetica》1985,29(2):163-168

Summary The propagator matrix is expressed in terms of cross-products of spherical Bessel functions and their derivatives. A fast computational algorithm is suggested. The matrix form of the variational principle with the boundary term is derived.

---

u nu u u u, n¶rt; u¶rt; nu¶rt;u uu u u u nuo¶rt;. ¶rt; au u . ¶rt; u uau nuuna u .

  相似文献   

On the possibilities of horizontal propagation ofPc1 pulsations in the ionosphere     

Karel Prikner  Vladimír Vagner  Reviewer M. Hvoždara 《Studia Geophysica et Geodaetica》1985,29(3):269-279

Summary The vertical distribution of the contribution of the energy flux density due to the Alfvén(ordinary) wave, guided by the geomagnetic field(and propagating through the ionosphere to the Earth's surface) in the horizontal direction is demonstrated in the mechanism of the horizontal propagation of the Pc1 signal. The distribution with height is shown of the variations of the polarization characteristics of the propagating wave(e.g. the rotation of the polarization plane, changes in ellipticity, attenuation, etc.), which are the result of coupling in the denser layers of the low ionosphere in which also suitable isotropic(extraordinary) modes are generated. The results obtained using the method described in[4, 13] are demonstrated on a model of the daytime ionosphere under incidence of ordinaryL-modes, frequency f=0.3 Hz, and various meridional angles at the ionosphere.

---

auauma anmau uaa Pc1 naa m an¶rt;u ¶rt;u nmmu ma uu uma anauu maum n n¶rt; , anma u nmu. naa m an¶rt;u uu aamumu nuauu anma (nauau nmu nuauu, uu unmumu, amau u m.¶rt;.), m m ¶rt;mu au¶rt;mu na uu u . ¶rt; mum n¶rt;¶rt;u umn() ¶rt;. mam num m¶rt; [4, 13] ¶rt;mua ¶rt;u ¶rt; u nu na¶rt;uu a u L-¶rt; amm f=0,3 n¶rt; au u¶rt;uau au.

  相似文献   

Geochemical Investigations of Stratabound Gunga Barite Deposits of Khuzdar (Balochistan), Pakistan     

Viqar HUSAIN  Hameedullah KHAN  Klaus GERMANN  Karel ZAK 《Resource Geology》2002,52(1):49-58

Abstract: The Gunga barite deposits occur in carbonate clastic marine sequence of Jurassic age. These rocks are widely spread in Khuzdar-Lasbela belt which host important stratabound barite and zinc-lead deposits of Pakistan. These rocks are intricately folded and extensively faulted. The Gunga are low temperature hydrothermal deposits occurring as a series of disconnected lenses a few meters thick. Two mineralized horizons are recognized: barite in the upper zone, sphalerite and galena in the lower zone. Four types of barite mineralization occurs in Gunga stratabound replacement associated with 1) fracture filling, 2) open space fillings in solution collapsed breccia, 3) replacement in fault, and 4) veinlets associated with all these three types. The wall rocks of the Gunga deposits have also been altered by silicification, leaching and ferruginization.
The sulfur isotope values of most of the Gunga barite samples range from 23.8 to 27.8 per mil with an average of 26.4 per mil, which is very close to the average of isotopic values of epigenetic carbonate hosted Late Paleozoic Missouri barite deposits. The Gunga like other barite and sulfide deposits of Khuzdar-Lasbela belt are Mississippi Valley type, stratabound and of replacement origin precipitated from connate brines expelled during the incipient rifting of India from Gondwana land in the Late Jurassic and Early Cretaceous periods. The low content of copper, lead and zinc in the Gunga barite deposits suggests that these deposits were not formed in proximity to an igneous source of the ore solution.
The Gunga deposits are epigenetic and stratabound as their mineralization is structure controlled. There is an evidence of transgressive nature of host rock and wall rock alteration which are absent in stratiform or bedded deposits.  相似文献