Solar Origin of the Radio Attributes of a Complex Type III Burst Observed on 11 April 2001

International audienceWe report here on the solar origin of distinctive radiation characteristics observed for a decametric type III solar radio burst that was associated with a major solar flare and CME on 11 April 2001. The associated decimeter (Ondrejov) and meter (Potsdam) wavelength emissions, as well as the GOES soft X-ray lightcurve, suggest that there were two successive events of energy release and electron acceleration associated with this solar eruption. The Nançay radioheliograph images and additional evidence of plasmoid propagation suggest that the second event of electron acceleration resulted from coronal reconfigurations, likely caused by the erupting CME. These observational analyses provide new insights into the physical origin of the distinguishing characteristics of complex type III-like radio emissions that are typically observed at decameter wavelengths during major solar eruptive events

On two distinct shocks during the flare of 9 July, 1996

Due to the emission of shock-accelerated electrons, broadband radio observations display propagating super-Alfvenic shock waves in the low corona ('type II bursts'). We study the July 9, 1996 flare (AR NOAA 7978) focusing on the aspect of shock generation. This event's radio spectrogram shows two different type II bursts in sequence. Radio imaging data (Paris - Meudon Observatory) reveal that both bursts appear at different sites above the H#alpha# flare. The driver of the first type II burst seems to propagate with twice the speed of the second one. The projected source site of the first type II burst (seen earlier and at higher frequencies) is spatially situated further away from the H#alpha# flare site than the source of the second type II burst. We try to understand this by comparing with Yohkoh soft X-ray images. The first shock source occurs near the top of high soft X-ray loop structures. Its driver can be a guided fast mode magnetic disturbance. The second type II source appears in between two high soft X-ray loop systems. This might be a piston driven disturbance powered by an evaporation front. We get a consistent picture by assuming a very inhomogeneous Alfven speed in the active region's atmosphere, only. (orig.)Available from TIB Hannover: RR 7310(99-05) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Hanford Immobilized LAW Product Acceptance: Initial Tanks Focus Area Testing Data Package

A matrix of 55 glasses was developed and tested with the aim to identify the impact of glass composition on the long-term corrosion behavior and to develop an acceptable low-activity waste glass composition region. Of the 55 glasses, 45 were designed to systematically vary the glass composition and 10 were selected because large and growing databases on their corrosion characteristics had accumulated. The performance of these 55 glasses in the vapor-phase hydration test (VHT) and product consistency test (PCT) were characterized. VHT's were performed at temperatures between 150?C and 300?C for times up to 280 days; preliminary corrosion rates and type of alteration products were identified. PCTs were performed at 90?C with glass surface area's to solution volumes (S/V) of 2000 m-1 for 7 days and S/V of 20 000 m-1 for 10 h, 100 h, and 1000 h. The corrosion extents by PCT were determined as functions of time from solution composition analyses