The Solar Connection of Enhanced Heavy Ion Charge States in the Interplanetary Medium: Implications for the Flux-Rope Structure of CMEs

We investigated a set of 54 interplanetary coronal mass ejection (ICME) events whose solar sources are very close to the disk center (within ±?15^° from the central meridian). The ICMEs consisted of 23 magnetic-cloud (MC) events and 31 non-MC events. Our analyses suggest that the MC and non-MC ICMEs have more or less the same eruption characteristics at the Sun in terms of soft X-ray flares and CMEs. Both types have significant enhancements in ion charge states, although the non-MC structures have slightly lower levels of enhancement. The overall duration of charge-state enhancement is also considerably smaller than that in MCs as derived from solar wind plasma and magnetic signatures. We find very good correlation between the Fe and O charge-state measurements and the flare properties such as soft X-ray flare intensity and flare temperature for both MCs and non-MCs. These observations suggest that both MC and non-MC ICMEs are likely to have a flux-rope structure and the unfavorable observational geometry may be responsible for the appearance of non-MC structures at 1 AU. We do not find any evidence for an active region expansion resulting in ICMEs lacking a flux-rope structure because the mechanism of producing high charge states and the flux-rope structure at the Sun is the same for MC and non-MC events.     

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Zur Bestimmung des Schneeanteils am Gesamtniederschlag

Zusammenfassung Aus den Monatsberichten einiger hydrographischer Stationen der Ostalpen in verschiedenen Höhenlagen wird bestimmt, welche Niederschlagsmengen 1 cm der gemessenen Neuschneehöhen entsprechen, im Monats- und im Jahresmittel. In Abhängigkeit von der Höhenlage weist die Niederschlagsmenge pro Zentimeter Neuschneehöhe ein ausgeprägtes Minimum bei 1350 m Seehöhe auf. Durch Multiplikation des der Seehöhe entsprechenden Wertes dieser Kurve mit der an einer Station der Ostalpen gemessenen Neuschneehöhe der Periode 1896/97–1915/16 erhält man den Schneeanteil dieser Station am Gesamtniederschlag. Die auf diese Art bestimmten Anteilmengen sind in der Regel dann größer bzw. kleiner als die nachV. Conrad berechneten Werte, wenn die Anomalien der jährlichen Neuschneehöhen nachE. Ekhart positiv bzw. negativ sind.

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Summary On the base of monthly reports of several hydrographic stations in the Eastern Alps, the amounts of precipitation corresponding to 1 cm of fresh snow-depth have been calculated in the monthly and yearly average. As a function of the altitude the amount of precipitation per cm fresh snow-depth shows a marked minimum at the altitude of 1350 m. By multiplication of the fresh snow-depths, measured at a station of the Eastern Alps during the period 1896/97–1915/16, with the corresponding value of the above curve the snow fraction of the total precipitation of this station can be obtained. As a rule, the fractions determined in this way are greater or smaller than those calculated byV. Conrad according as the anomalies of the yearly fresh snow-depths given byE. Ekhart are respectively positive or negative.

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Résumé On calcule la quantité d'eau météorique correspondant à 1 cm. de neige fraîche (moyennes mensuelles et annuelles) sur la base des rapports mensuels de quelques stations hydrographiques des Alpes orientales. Cette quantité, considérée en fonction de l'altitude, présente un minimum net vers 1350 m. En multipliant la valeur correspondant à l'altitude d'une station des Alpes orientales où furent mesurées les hauteurs de neige fraîche pendant la période 1896/97 à 1915/16 par cette hauteur même, on obtient la fraction en neige des précipitations totales en ce point. Les fractions ainsi calculées sont dans la règle plus grandes ou plus petites que les valeurs établies parV. Conrad selon que les anomalies des hauteurs annuelles de neige fraîche, d'aprèsE. Ekhart, sont respectivement positives ou négatives.

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Mit 2 Textabbildungen.     

Spatial Analysis Techniques as Successful Mineral-Potential Mapping Tools for Orogenic Gold Deposits in the Northern Fennoscandian Shield,Finland

Geoscientific Information Systems (GIS) provide tools to quantitatively analyze and integrate spatially referenced information from geological, geophysical, and geochemical surveys for decision-making processes. Excellent coverage of well-documented, precise and good quality data enables testing of variable exploration models in an efficient and cost effective way with GIS tools. Digital geoscientific data from the Geological Survey of Finland (GTK) are being used widely as spatial evidence in exploration targeting, that is ranking areas based on their exploration importance. In the last few years, spatial analysis techniques including weights-of-evidence, logistic regression, and fuzzy logic, have been increasingly used in GTK’s mineral exploration and geological mapping projects. Special emphasis has been put into the exploration for gold because of the excellent data coverage within the prospective volcanic belts and because of the increased activity in gold exploration in Finland during recent years. In this paper, we describe some successful case histories of using the weights-of-evidence method for the Au-potential mapping. These projects have shown that, by using spatial modeling techniques, exploration targets can be generated by quantitatively analyzing extensive amounts of data from various sources and to rank these target areas based on their exploration potential.     

Fission tracks in minerals: Annealing kinetics,track structure and age correction

It is shown that the annealing kinetics of fission tracks in apatite can be described by a sum of exponential decay functions. From an analysis of the temperature dependence of this annealing law it is concluded that the etchability of fission tracks is due to extended defects, i.e. systems of dislocation loops. The multiexponential annealing law is also applied to prove that the plateau correction method is basically correct, but rather as a method for determining a lower limit than the “true” fission track age.