SYNTHETIC IMAGES OF THE SOLAR CORONA FROM
OCTREE REPRESENTATION OF 3-D ELECTRON DISTRIBUTION

A.LLebaria
LAS (CNRS)

D.Vibert
LAS (CNRS)

T.Netter
LAS (CNRS)

L.Balard
LAS (CNRS)

P.Lamy
LAS (CNRS)

Session ID: P5.09   Type: poster

Abstract:

Empirical and theoretical modeling of the 3-D structures of the solar corona (streamers, plumes, etc) faces the tremendous amount of data needed to represent phenomena with a large dynamic scale both in size and magnitude. A 1000x1000x1000 cube of data of uniform resolution uses a minimum of 1Go of computer memory. Octree representation of 3-D coronal electron distributions offers the right compromise between resolution and size. The S-tree structure allows for a large dynamic scale, and have been chosen here for the empirical modeling of coronal structures. It takes advantage from all low resolution space to keep the size of the useful data manageable. A resolution better than per axis is obtained with less than 50Mo of file size (for a complex model), i.e. a compression ratio better than 100. The paper presents the algorithms used to buid these representations and the methods used to compute the light scattered by the coronal electrons and the line-of-sight integration to generate synthetic images projected onto the plane of the sky. A typical 512x512 image can be obtained in less than 30min from an octree representation, using a standard low cost worksatation with 64 Mo of memory. A high resolution ( per axis) specific electron distribution can be obtained in less than 4 h with the same processor.

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