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  • 1
    Electronic Resource
    Electronic Resource
    A quantitative model for cyclotron wave-particle interactions at the plasmapause (1998)
    Springer
    Annales geophysicae 16 (1998), S. 322-330 
    Details
    ISSN: 0992-7689
    Keywords: Magnetospheric physics ; Energetic particles ; Precipitating and trapped ; Plasma waves and instabilities
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The formation of a zone of energetic electron precipitation by the plasmapause, a region of enhanced plasma density, following energetic particle injection during a magnetic storm, is analyzed. Such a region can also be formed by detached cold plasma clouds appearing in the outer magnetosphere by restructuring of the plasmasphere during a magnetic storm. As a mechanism of precipitation, wave-particle interactions by the cyclotron instability between whistler-mode waves and electrons are considered. In the framework of the self-consistent equations of quasi-linear plasma theory, the distribution function of trapped electrons and the electron precipitation pattern are found. The theoretical results are compared with experimental data obtained from NOAA satellites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00585-998-0322-4
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  • 2
    Electronic Resource
    Electronic Resource
    Strong localized variations of the low-altitude energetic electron fluxes in the evening sector near the plasmapause (1997)
    Springer
    Annales geophysicae 16 (1997), S. 25-33 
    Details
    ISSN: 0992-7689
    Keywords: Ionosphere (particle precipitation wave-particle interaction) ; Magnetospheric Physics (plasmasphere)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Specific type of energetic electron precipitation accompanied by a sharp increase in trapped energetic electron flux are found in the data obtained from low-altitude NOAA satellites. These strongly localized variations of the trapped and precipitated energetic electron flux have been observed in the evening sector near the plasmapause during recovery phase of magnetic storms. Statistical characteristics of these structures as well as the results of comparison with proton precipitation are described. We demonstrate the spatial coincidence of localized electron precipitation with cold plasma gradient and whistler wave intensification measured on board the DE-1 and Aureol-3 satellites. A simultaneous localized sharp increase in both trapped and precipitating electron flux could be a result of significant pitch-angle isotropization of drifting electrons due to their interaction via cyclotron instability with the region of sharp increase in background plasma density.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00585-997-0025-2
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  • 3
    Electronic Resource
    Electronic Resource
    Modeling of nonstationary electron precipitation by the whistler cyclotron instability (1998)
    Springer
    Annales geophysicae 16 (1998), S. 1455-1460 
    Details
    ISSN: 0992-7689
    Keywords: Magnetospheric physics (Auroral phenomena; Energetic particles, precipitating; Storms and substorms)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract We study a simple self-consistent model of a whistler cyclotron maser derived from the full set of quasi-linear equations. We employ numerical calculations to demonstrate dependencies of pulsation regimes of whistler-mode wave interactions with energetic electrons on plasma parameters. Possible temporal evolution of those regimes in real conditions is discussed; calculations are compared with case-study experimental data on energetic electron precipitation pulsations. A reasonable agreement of the model results and the observations has been found.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00585-998-1455-1
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  • 4
    Electronic Resource
    Electronic Resource
    Auroral pulsations and accompanying VLF emissions (1998)
    Springer
    Annales geophysicae 17 (1998), S. 66-78 
    Details
    ISSN: 0992-7689
    Keywords: Magnetospheric physics (auroral phenomena; magnetosphere-ionosphere interactions) ; Space plasma physics (wave-particle interactions)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Results of simultaneous TV observations of pulsating auroral patches and ELF-VLF-emissions in the morning sector carried out in Sodankylä (Finland) on February 15, 1991 are presented. Auroral pulsating activity was typical having pulsating patches with characteristic periods of about 7 s. Narrow-band hiss emissions and chorus elements at intervals of 0.3–0.4 s formed the main ELF-VLF activity in the frequency range 1.0–2.5 kHz at the same time. The analysis of auroral images with time resolution of 0.04 s allowed perfectly separate analysis of spatial and temporal variations in the auroral luminosity. Mutual correspondence between the behaviour of the luminous auroral patches and the appearance of ELF noise type hiss emissions and VLF chorus trains was found in two intervals chosen for analysis. While the hiss emissions were associated with the appearance of luminosity inside a limited area close to the zenith, the structured VLF emissions were accompanied by rapid motion of luminosity inside the area. The spatial dimension of the pulsating area was about 45–50 km and luminosity propagated inside it with velocity of about 10–12 kms. We discuss a new approach to explain the 5–15 s auroral pulsation based on the theory of flowing cyclotron maser and relaxation characteristics of ionosphere.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00585-999-0066-9
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  • 5
    Electronic Resource
    Electronic Resource
    Connection between the upper ionospheric region of VLF chorus occurrence and the plasmapause position (1986)
    Springer
    Studia geophysica et geodaetica 30 (1986), S. 404-410 
    Details
    ISSN: 1573-1626
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences , Physics
    Description / Table of Contents: Summary The occurrence zone of the VLF chorus in the upper ionosphere appears at L-shells lower than plasmapause position Lpp; with increasing geomagnetic activity the spatial dimension of the zone diminishes, its upper boundary being shifted in correspondence with the plasmapause position, the lower remaining practically without change(L=2.0÷2.5). Calculations of propagation paths have shown that the similarity of the VLF chorus spectrum at different upper-ionospheric latitudes as well as the large spatial dimension of the zone of observation can be explained as special features in the propagation of VLF waves from an equatorial source, starting in the vicinity of the plasmapause with different initial normal angles.
    Notes: Резюме Зонa регuсmрaцuu ОНЧ хоров в верхнеŭ uоносфере рaсnоложенa в облaсmu L-оболочек, меньшuх Lpp (Lpp — nоложенuе nлaзмоnaузы); с увелuченuем мaгнumноŭ aкmuвносmu ее nросmрaнсmвенныŭ рaзмер уменьшaеmся, nрuчем верхняягрaнuцa зоны смещaеmся в сооmвеmсmвuu с uзмененuем nоложенuя nлaзмоnaузы, a нuжняя осmaеmся nрaкmuческu неuзменноŭ(L=2.0÷2.5). Рaсчеmы mрaекmорuŭ nокaзывaюm, чmо nо¶rt;обuе сnекmров ОНЧ хоров нa рaзлuчных шuроmaх в верхнеŭ uоносфере, maкже кaк большоŭ nросmрaнсmвенныŭ мaсшmaб зоны нaблю¶rt;енuя, могуm быmь объяснены особенносmямu рaсnросmрaненuя ОНЧ волн оm эквamорuaльного uсmочнuкa, рaсnоложенного в узкоŭ облaсmu около nлaзмоnaузы, но uмеющuх рaзлuчные углы волновоŭ нормaлu.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01646383
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  • 6
    Electronic Resource
    Electronic Resource
    LHR whistlers (1990)
    Springer
    Studia geophysica et geodaetica 34 (1990), S. 137-146 
    Details
    ISSN: 1573-1626
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences , Physics
    Description / Table of Contents: Summary A type of whistler with unusual dispersion near the LHR frequency has been found, in a number of VLF experiments aboard low-orbiting Intercosmos satellites. These “LHR whistlers” are thought to be the result of transformation of the common whistler mode waves into quasi-electrostatic waves, as they propagate near the LHR frequency. The mechanism generating the LHR whistlers for downgoing whistler waves is discussed. It is shown how the characteristic features of the LHR whistlers reflect the dynamic changes in the outer ionosphere at midlatitudes.
    Notes: Резюме В ря¶rt;е ОНЧ эксnерuменmов, выnолненых нa нuзколеmящuх сnуmнuкaх серuu „Инmеркосмос“, был нaŭ¶rt;ен mun свuсmов с необычноŭ ¶rt;uсnерсuеŭ вблuзu чaсmоmы нuжне¶rt;о ¶rt;uбрu¶rt;но¶rt;о резонaнсa (НГР). Эmu „НГР свuсmы“ рaссмamрuвaюmся кaк резульmam mрaнсформaцuu обычных свuсmовых волн в квaзuэлекmросmamuческuе волны в nроцессе рaсnросmрaненuя вблuзu чaсmоmы НГР. Обсуж¶rt;aеmся мехaнuзм вознuкновенuя НГР свuсmов ¶rt;ля свuсmовых волн, рaсnросmрaняющuхся оm большuх высоm к Земле. Покaзaно, кaкuм обрaзом хaрaкmерные особенносmu НГР свuсmов оmрaжaюm ¶rt;uнaмuческuе uзмененuя во внещнеŭ uоносфере сре¶rt;нuх шuроm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02295833
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  • 7
    Electronic Resource
    Electronic Resource
    Lower hybrid resonance spherics (1990)
    Springer
    Studia geophysica et geodaetica 34 (1990), S. 269-277 
    Details
    ISSN: 1573-1626
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences , Physics
    Notes: Summary After a fractional-hop whistler, a trace of limited frequency range with somewhat higher dispersion, markedly growing when approaching the lower cutoff frequency, is frequently observed on spectrograms of broadband VLF measurements made by satellites moving in the outer ionosphere. This phenomenon, which we have called “LHR spheric”, has been studied on VLF measurements made by the Interkosmos-14 satellite in the height range of 500–1700 km. The results show that LHR spherics are created by the same mechanism as LHR whistlers that sometimes appear after ducted whistlers. In this event, it is a part of the electromagnetic energy radiated by a lightning flash which, on passing trough the ionosphere, has been transformed to quasi-electrostatic resonance waves. They reach the satellite in the same way as whistler-mode waves. Transformation of a part of the energy radiated by a lightning flash to electrostatic quasi-resonance waves is possible in the ionosphere due to the scattering of the original whistler wave on small-scale turbulence.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02295933
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  • 8
    Electronic Resource
    Electronic Resource
    On the characteristics of vlf emissions in the upper ionosphere and on the ground (1981)
    Springer
    Studia geophysica et geodaetica 25 (1981), S. 81-86 
    Details
    ISSN: 1573-1626
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences , Physics
    Notes: Резюме Анaлuзuровaлuсь uзлученuя хорово о muna нa f〉1,5 кГц, зaре uсmрuровaнные о¶rt;новременно нa сnуmнuкaх серuu „Инmеркосмос“ u нa ¶rt;вух нaземных сmaнцuях. В уmреннuе чaсы в мa нumовозмущенное время сnекmр эмuссuŭ, ре uсmрuруемых нa сmaнцuu Пaнскa Вес (L=2,1) nо¶rt;обен сnекmру эмuссuŭ в Ловозеро (L=5). Эmо обсmояmельсmво оворum об общносmu uсmочнuкa эмuссuŭ, ре uсmрuруемых нa эmuх сmaнцuях. Анaлuз зоны uзлученuŭ нa сnуmнкке выявляеm, чmо онa uмееm nросmрaнсmвенныŭ рaзмер 2000–3000 км u рaсnоложенuе в верхнеŭ uоносфере нa L=2,2–5,9. Нauлучщее сооmвеmсmвuе сnекmрaльных хaрaкmерuсmuк нaземных u сnуmнuковых эмuссuŭ нaблю¶rt;aеmся в верхнеŭ uоносфере в узкоŭ облaсmu мaксuмумa uзлученuŭ нa L ∼ 3,5. Покaзaно, чmо нaземные сmaнцuu Пaнскa Вес u Ловозеро ¶rt;aже нaхо¶rt;ясь вне nроекцuu зоны uзлученuя нa Землю, ре uсmрuруюm ОНЧ эмuссuu nо¶rt;обные нaблю¶rt;aемым нa сnуmнuке. Тaкuм обрaзом можно nре¶rt;nоложumь, чmо облaсmь нa L ∼ 3,5, ¶rt;е нaблюбaюmся мaксuмум uзлученuя u нauлучщее сооmвесmвuе сnекmрaльных хaрaкmерuсmuк нaземных u сnуmнuковых эмuссuŭ, связaнa с ¶rt;aкmuровaнным рaсnросрaненuем в рaŭоне nлaзмоnaузы. И чmо uменно в эmоŭ облaсmu осущесmвляюmся нauболее блa оnрuяmные условuя ¶rt;ля выхо¶rt;a ОНЧ сu нaлов к Земле с nосле¶rt;ующuм рaсnросmрaненuем uх в волново¶rt;е Земля — uоносферa.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01613563
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  • 9
    Electronic Resource
    Electronic Resource
    On latitudinal variations of temporal characteristics of the VLF chorus in the upper ionosphere (1986)
    Springer
    Studia geophysica et geodaetica 30 (1986), S. 411-416 
    Details
    ISSN: 1573-1626
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying , Geosciences , Physics
    Description / Table of Contents: Summary The elements of the VLF chorus, observed simultaneously at a ground station and satellite in polar orbit, can be used to determine the differences in the arrival times of waves Δτ and their dependence on latitude. Mostly Δτ does not change practically over a wide range of latitudes, however, in some cases it may increase appreciably at low value of L. Model computations of the propagation time, based on the assumption that the source of the chorus is located close to the equatorial plane, have indicated the possibility of explaining the increase in Δτ at low latitudes by the presence of a step in the electron density profile close to this plane.
    Notes: Резюме Ооновременные нaблю¶rt;енuя хоровых элеменmов нa Земле u нa нuзколеmящем сnуmнuке с nрunолярноŭ орбumоŭ nозволяюm оnре¶rt;елumь рaзносmu времен uх nрuхо¶rt;a Δτ maкже кaк u uх шuроmную зaвuсuмосmь Δτ(L). В большuнсmве случaев Δτ очень мaло меняеmся в большом ¶rt;uanaзоне шuроm, но в некоmорых случaях нaблю¶rt;aеmся знaчumельное увелuченuе Δτ нa мaлых L-оболочкaх. Рaсчеm времен рaсnросmрaненuя в nре¶rt;nоложенuu эквamорuaльного uсmочнuкa ОНЧ хоров nокaзывaеm возможносmь обяснumь увелuченuе Δτ нa нuзкuх шuроmaх нaлuчuем сmуnенькu в рaсnре¶rt;еленuu элекmронноŭ конценmрaцuu в эквamорuaльноŭ nлоскосmu.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01646384
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