Klein, K.-L. and Aurass, H. and Soru-Escaut, I. and Kálmán, Béla (1997) Electron acceleration sites in a large-scale coronal structure. Astronomy and Astrophysics, 320. pp. 612-619. ISSN 0004-6361
Radio observations and interplanetary particle measurements have shown that even in the absence of conspicuous violent processes in the low atmosphere (such as Hα ﬂares) electrons are accelerated in the corona, most likely at higher altitudes than during ﬂares (≥0.5 R above the photosphere). The paper presents direct evidence on the acceleration sites from a case study of radio, visible light and soft X-ray observations: electrons are repeatedly accelerated in a large-scale coronal structure which is identiﬁed with a streamer in coronographic observations. Energy is simultaneously released in an active region near the base of the structure and at a height of ∼1 R , over several hours before the large-scale structure erupts. Energy input is observed in at least two emerging active regions underneath the streamer. The coronal conﬁguration is three-dimensional, overlying a whole quadrant of the Sun. It is argued that the observations trace multiple sites of energy release presumably in current sheets embedded within the streamer, in agreement with scenarios developed for the acceleration of electrons seen in the corona and at 1 AU, and for the evolution of large-scale coronal structures towards eruption.
|Subjects:||Q Science / természettudomány > QB Astronomy, Astrophysics / csillagászat, asztrofizika|
|Depositing User:||Mr András Holl|
|Date Deposited:||06 Apr 2010 05:56|
|Last Modified:||30 Nov 2010 14:45|
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