Mhd Leaky Waves in a Layered Plasma: II Mechanisms of Leakage     

A.G. González  J. Gratton  S. Farina 《Astrophysics and Space Science》1997,256(1-2):297-301

The application of Fourier analysis to study leaky waves has the advantage of simplicity, but it is not clear why the complex roots of the dispersion relations represent leaky waves, nor how the leakage occurs. We investigate the different kinds of leakage that can occur in a three layer plasma, and to which Fourier pseudomodes they are associated. We find four basic mechanisms, called surface mode ..., single interface ..., trapped wave ... and lost insulation leakage. These mechanisms appear in pure form only near certain limiting cases, in which the parameters of the problem take some special values. As soon as the parameters depart significantly from the limiting values, the behavior of the leaky wave complicates and mixtures of the mechanisms occur, in varying amounts. In consequence different points of the same complex branch of the spectrum may correspond to different mechanisms. All the complex branches of the spectrum correspond to leaky waves, but in general it is not possible to classify them according to type of leakage, except close to a limiting case. Since in a three layer configuration there are many of these, the spectrum of leaky waves is very complicated.  相似文献   

L. Bassani and G. di Cocco (eds.), Imaging in High Energy Astronomy     

Fárník  František 《Solar physics》1997,175(1):206-206

  相似文献   

Book reviews     

Zdeněk Kopal 《Earth, Moon, and Planets》1970,1(3):426-426

  相似文献   

The lunar science conference,Houston, Texas,U.S.A., January 5–8, 1970     

Zdeněk Kopal 《Earth, Moon, and Planets》1970,1(3):352-402

  相似文献   

Sobre el caracter general de la clasificacion de las bahias geomagneticas y su ley de aparicion durante el dia     

Rev. A. Romañá 《Pure and Applied Geophysics》1950,18(1):148-154

Summary A comparative study of the geomagnetic bays at the Observatories of Cuajimalpa and Teoloyucan (Mexico) and Tortosa, shows: 1) that the grouping of the bays into a certain number of fundamental types, and that the tendency of their frequency maxima to recur in a cyclical order during the day, are general features of geomagnetic bays, at least for all middle geomagnetic latitudes; 2) that the relative importance of the different types and the hour of their maxima varies according to the geomagnetic latitude of the Observatory where the bays are recorded.

---

Résumé En comparant les baies géomagnétiques enregistrées aux Observatoires de Cuajimalpa et Teoloyucan (Mexique) avec celles observées à Tortosa, on examine la validité générale de la classification des baies établie à l'Observatoire de l'Ebre et de la loi de succession des différents types le long du jour. L'on arrive aux conclusions suivantes: 1^o La classification des baies géomagnétiques en un certain nombre de types fondamentaux, de même que la tendence à l'apparition de leurs maxima de fréquence dans un ordre cyclique pendant la journée, a un caractère général, tout au moins pour les latitudes géomagnétiques moyennes; 2^o L'importance relative des différents types et l'heure d'apparition de leurs maxima varie d'un Observatoire à l'autre, d'après leur latitude géomagnétique.

  相似文献   

Kondensationskernzähler mit automatischer Registrierung     

F. Verzár 《Meteorology and Atmospheric Physics》1952,5(3):372-376

  相似文献   

Die Verlässlichkeit der Eötvösschen Drehwagen     

Dr. Desider Pekár 《Pure and Applied Geophysics》1948,13(1-2):4-5

Ohne Zusammenfassung  相似文献   

Misure di magnetismo terrestre in Ungheria     

Prof. Dr. Carlo Kántás 《Pure and Applied Geophysics》1948,13(1-2):11-19

  相似文献   

Электрооптический Дальномер с Кварцевым Модулятором     

Bořivoj Delong  Bohuslav Sokolík  Přemek Neumann 《Studia Geophysica et Geodaetica》1961,5(1):8-20

  相似文献   

Food gardens as important elements of urban agriculture: Spatio-developmental trends and future prospects for urban gardening in Czechia     

Jana Spilková  Jiří Vágner 《Norsk geografisk tidsskrift. Norwegian journal of geography》2018,72(1):1-12

The main research goals of the article are to explain the historical context of urban food gardens in Czechia, to describe the current spatial pattern of allotment gardens, and to introduce and analyse recent trends in urban gardening. The main method for achieving the first goal was a literature study. For the second goal, geographical mapping and analysis of data relating to the spatial distribution of allotment gardens were used. For the third goal, mapping together with analysis of semi-structured interviews carried out in community gardens in Prague were used. The analysis showed a strong tradition of urban agriculture and urban food gardening activities in Czechia. Both allotment gardens and newly emerged community gardens were concentrated mainly in the biggest cities and in areas with a rich industrial and mining tradition. This finding supports the significance of gardening as an important element of urban agriculture. However, uncertainty regarding land tenure and long-term sustainability were among the greatest obstacles for the future of allotment and community gardens. The authors’ main recommendations are that urban agriculture should be included as primary land use in sustainable planning and there should be broader community involvement in planning and decision-making processes.  相似文献