Shortening of periods of electromagnetic pulsations and two periods in main phase of geomagnetic storm     

Karel Prikner 《Studia Geophysica et Geodaetica》1963,7(3):252-261

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Daily variations of the characteristics of beating-typePc3 (Bpc3) pulsations     

Jaroslav Střeštík  Karel Prikner  Karel Dobeš  Reviewer M. Hvoždara 《Studia Geophysica et Geodaetica》1973,17(1):27-35

Summary The spectra of nearly 100 samples of Bpc3 pulsations were computed in the X and Y components of data from the Budkov Observatory. These spectra were used to study the daily variations of the fundamental characteristics of the pulsations, the frequency f ₀ and amplitude A ₀ of the main spectral peaks. The daily variation of the ellipticity of the polarization ellipses of oscillations in frequency f ₀ was also studied in the XY-plane.Part of these results was reported at the XVth General Assembly of the IUGG, Moscow, August 1971.  相似文献   

Spectral analysis of geomagneticPc3 pulsations recorded at the observatories of Budkov and Belsk     

Jaroslav Střeštík  Karel Prikner  Reviewer M. Hooždara 《Studia Geophysica et Geodaetica》1977,21(2):159-167

Summary The numerical method of Fourier's spectral analysis is used to treat 29 pairs of samples of pc3 pulsations recorded at the observatories of Budkov (Czechoslovakia) and Belsk (Poland). The amplitude, frequency and phase characteristics of their spectra are compared. The polarization characteristics of the spectral frequency components of pulsations recorded at both observatories are compared in a quasi-stationary approximation of a plane oscillation.  相似文献   

Polarization characteristics of ulf electromagnetic waves in an inhomogeneous anisotropic ionosphere of the Earth     

Karel Prikner  Reviewer M. Hvoždara 《Studia Geophysica et Geodaetica》1979,23(2):174-188

Summary Drawing on [6], the height profiles of local complex polarization and local polarization characteristics of electromagnetic waves in several models of the Earth's ionosphere are analysed. The profiles were obtained with the aid of a computer program for modelling propagating [5]. The analysis was carried out a) for a flxed given configuration of the external magnetic field of the EarthB ₀ at a number of discrete frequencies f<5 Hz, b) for chosen model of the ionosphere at a fixed given frequency f=1 Hz and in connection with a change of the dip of the lines of force and of the magnitude of the external (homogeneous) magnetic field|B ₀|, c) for various models at f=1 Hz and a varying configuration of the external magnetic field, reflecting the change in geomagnetic latitude. The results of the analysis will serve as an aid to the interpretation of the results of solving the problem of wave propagation through the ionosphere.  相似文献   

Frequency-time analysis of geomagnetic beating-type pulsationsPc3     

Karel Prikner  Jaroslav Střeštík  Karel Dobeš  Reviewer M. Hvoždara 《Studia Geophysica et Geodaetica》1974,18(3):266-273

Summary The mechanism of beating of Pc3 type pulsations is studied. Using the method of numerical computation of a sonagram (the method of frequency-time analysis) a set of samples of pulsations from the Budkov Observatory is treated (1968–1969) mostly at K-indices equal to 2–3. By comparing f–t diagrams with the spectra of the samples an attempt has been made at interpreting the beating as a superposition of the frequency components, contained in the pulsation signal. In most observed cases it is possible to determine two close frequencies, the difference of which is on the average =5.4 mHz. The average carrier frequency of the samples was =37.6 mHz, and the average frequency of the beating =2.7 mHz. The interval of observed values of f_B amounted to 1–5 mHz. A tendency was observed for f_B to increase with increasing degree of disturbance of the geomagnetic field.  相似文献   

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.

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

Spatial features of mid-latitude field-line resonances from simultaneous ground-satellite measurements     

K. Prikner 《Annales Geophysicae》1996,14(7):699-706

Three series of simultaneous pulsation measurements (f<0.06 Hz) on the Freja satellite and at the Budkov Observatory have been spectrally processed (FFT) in 6-min intervals of Freja’s transits near the local Budkov field line. Doppler-shifted, weighted spectral-peak frequencies, determined in both transverse magnetic components in the mean field-aligned coordinate system on Freja, allowed the estimation, by comparison with the stable frequency at Budkov, of fundamental frequencies of the local magnetic-field-line resonance ranged from 13 to 17 mHz in two pulsation events analyzed, with K_p=2₊ to 0₊. The ratio of total amplitudes of the spectral-pulsation components on the ground and on Freja at an altitude of \sim1700 km (values <0.7) characterizes the transmissivity of the ionosphere. In the Pc3 frequency range this correlates well with simulation computations using models of the ionosphere under low solar activity.  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.

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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.

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The effect of interplanetary parameters as observed in geomagnetic storms in dependence on geomagnetic latitude     

Petronela Ochabová  Reviewer K. Prikner 《Studia Geophysica et Geodaetica》1986,30(4):331-344

Summary The purpose of this study was to determine to what extent the effect of interplanetary parameters is reflected in the separate storms in dependence on geomagnetic latitude. The results were obtained by studying 5 storms of February 1967 and 1968 recorded at 6 observatories between latitude 5.7° and 53.5° with small differences in local time. These results concern the dynamic pressure of the solar wind and the function of the interplanetary electric field, which approximates the plasma injection into the ring current. This is also associated with the decay time of the storm ring. In most cases the dependence of the effect of the investigated parameters on latitude was proved and expressed in terms of quantitative relations with a reasonable degree of correlation. The derived constants were used in a model of time variations of the storm-time geomagnetic field. The storm-time variations, constructed using this model, mostly agree, as regards their main features, with the real variations, whereas differences can be observed in details, namely of a local nature.

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mam maua maum, a nm uu nam naam u nu amuu auumu maum um. mam mm 5 , aumua a 1967. u 1968. m amuu um ¶rt;uana 5, 7°–53,5° nu auuu m u. mam aam ¶rt;uau ¶rt;au ma u uu nam mu n, m annuum uu na m. mu a u ana¶rt;a m ma. um a auum ma u¶rt; naam m um n¶rt;m¶rt;ua u a aa um nu ¶rt;mam mnu uu. nm u una ¶rt;u uuaum n u. ¶rt; auauu u am ¶rt;mumu, u ¶rt;ma mam m mu num a aama.

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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.

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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.

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