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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 109 records · Page 6

Stagnation Flow in Streamer Boundaries

It is possible for flow tubes adjacent to closed magnetic field lines on the boundaries of streamers to have spreading factors that change rapidly according to height. Mathematical models in this thin layer are prone to uncertainties. In this paper we use an analytical model of magnetically closed and adjacent open regions to calculate the spreading factor close to the closed field lines and near the flow on the open field lines. We recovered the shape of the closed field region, or helmet, and show the evolution of the helmet under increasing temperature. We also show why and when stagnation flow can occur in the area of the cusp at the top of the helmet.

Suess, S. T.↗

The chromospheric association of the metric type 3 bursts - implications concerning the acceleration of solar electrons and the active streamers

In two recent papers it was shown that the metric type 3 emission is closely related to a transient perturbation seen in absorption in the H alpha line. In addition, this perturbation sometimes triggers a flare, sometimes not. This can explain why the type 3 have a poor H alpha flare correlation rate and still are a typical flash phase emission when flare-associated. The characteristics are summarized of the new association proposed. It is assumed that 10 to 100 keV electrons are accelerated in connection with a particular kind of transient H alpha absorbing feature. For as yet undetermined reasons, this process would often, but not always, result in a more efficient acceleration coincident with the early phase of the optical flare. The possibilities that this process could lead occasionally to long lasting subrelativistic particle emissive region are explored.

Axisa, F.↗

Radio evidence for interplanetary streamers in the range 10-170 solar radii

Type III radio storms are observed by the radio experiment on board the International Sun Earth Explorer 3 out to 0.5-0.8 AU from the Sun, at a rate of 2 to 3 storms per solar rotation near solar maximum. They correlate with the type I and type III radio storms observed at higher frequencies, originating closer to the Sun. They are associated with an almost continuous injection of suprathermal electrons into the interplanetary medium. Some of the properties of the regions where the particles propagate are discussed, using the radio emission as a tracer.

Fainberg, J.↗