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Abstract
Context. This paper presents a method which can be used to calculate models of the global solar corona from observational data.
Aims. We present an optimization method for computing nonlinear magnetohydrostatic equilibria in spherical geometry with the aim to obtain selfconsistent solutions for the coronal magnetic field, the coronal plasma density and plasma pressure using observational data as input.
Methods. Our code for the selfconsistent computation of the coronal magnetic fields and the coronal plasma solves the nonforcefree magnetohydrostatic equilibria using an optimization method. Previous versions of the code have been used to compute nonlinear forcefree coronal magnetic fields from photospheric measurements in Cartesian and spherical geometry, and magnetostaticequilibria in Cartesian geometry. We test our code with the help of a known analytic 3D equilibrium solution of the magnetohydrostatic equations. The detailed comparison between the numerical calculations and the exact equilibrium solutions is made by using magnetic field line plots, plots of density and pressure and some of the usual quantitative numerical comparison measures.
Results. We find that the method reconstructs the equilibrium accurately, with residual forces of the order of the discretisation error of the analytic solution. The correlation with the reference solution is better than 99.9% and the magnetic energy is computed accurately with an error of < 0.1%. Conclusions. We applied the method so far to an analytic test case. We are planning to use this method with real observational data as input as soon as possible.
Original language  English 

Pages (fromto)  701706 
Number of pages  6 
Journal  Astronomy & Astrophysics 
Volume  475 
DOIs  
Publication status  Published  Nov 2007 
Keywords
 sun : corona
 sun : magnetic fields
 methods : numerical
 ELECTRICCURRENT SYSTEMS
 FREE MAGNETICFIELD
 FORCEFREE FIELDS
 MAGNETOSTATIC ATMOSPHERES
 3DIMENSIONAL STRUCTURES
 SOLAR CORONA
 RECONSTRUCTION
 EQUATIONS
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 1 Finished

Solar&Magnetospheric Plasma Theory PP/E1: Solar and Magnetospheric Plasma Theory
Neukirch, T., Hood, A. W., Parnell, C. E., Priest, E., Roberts, B. & Wright, A. N.
1/04/07 → 31/03/12
Project: Standard