On high-latitude convection field inhomogeneities,parallel electric fields and inverted-V precipitation events

Assuming a certain horizontal distribution of the convection field at a certain altitude above the ionosphere, the associated electric field and current distributions in a vertical plane are calculated using a model with finite current-dependent conductivity along the magnetic field lines. It is seen that given the kind of horizontal distribution of E₆ commonly observed by polar-orbiting satellites at inverted-V electron precipitation events, the calculated distribution of E_∥ is able to reproduce the basic spatial structure of the precipitation. It is also seen that the combined effect of a locally increased ionization within auroral forms and a large potential difference (ΔV)_∥ along the magnetic field lines at higher altitudes is a strong reduction of E₆ within the auroral forms. From the basic features of the electric field, it is concluded that an interpretation of auroral precipitation in terms of a static E_∥ may require a mechanism that can support a large (ΔV)_∥ even at relatively weak current densities and at the same time allow local enhancements of the parallel conductivity within the region of non-zero E_∥. It is suggested that the magnetic mirroring combined with gyro-resonant wave-particle interactions may be a suitable mechanism.     

I. Erdöl Ergebnisse der erdölgeologischen Erforschung Nordwestdeutschlands 1932–1947, ein Überblick

Ohne Zusammenfassung     

A check on some previously reported analyses of chondrites with exceptionally high content of sulphur,chromium or manganese

Some analyses of stony meteorites indicating a high content of sulphur, chromium or maganese have been checked. The high values previously reported are not confirmed.     

Gezeitenströme im Englischen Kanal

Zusammenfassung Die Gröen, die die Gezeitenstromellipse der HalbtagsgezeitM ₂ festlegen, werden kartenmäig dargestellt und ihre geographische Verteilung behandelt: Maximaler Gezeitenstrom, Eintritt des maximalen Gezeitenstroms, Richtung des maximalen Gezeitenstroms, Achsenverhältnis der Gezeitenstromellipse. Treten Gezeitenströme in einem inhomogenen Meer auf, dann wird den periodischen Bewegungen eine Translationsbewegung überlagert, die insofern bemerkenswert ist, als der Massentransport in der Bodenschicht landwärts und in der Oberschicht seewärts stattfindet. Eine Beziehung zwischen Austausch, Stromgeschwindigkeit und Dichte wird abgeleitet, die es gestattet, Zusammenhänge zwischen dem Auftreten der Sprungschicht und der maximalen Gezeitenstromgeschwindigkeit herauszustellen.

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Tidal currents in the English Channel

Summary The values which determine the current ellipse of the principal lunar (M ₂) tide are plotted on charts and their geographical distribution is discussed, viz.: Maximum tidal currents and when they occur, directions of maximum tidal currents, ratios between the major and minor axes of the ellipses of tidal currents. In the case of tidal currents in nonhomogeneous water a translational motion is superposed on the periodical one, this translation being particularly characterized by the fact that mass transfer is directed coastward in the bottom layer and seaward in the surface and subsurface layers. A relation between exchange, current velocity, and density is found allowing the pointing out of correlations between the occurrence of discontinuity layers and maximum velocities of tidal currents.

     

Kurt Grundlach zum Gedächtnis

Ohne Zusammenfassung