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Last modified: Fri Nov 9 16:37:03 2007.
Procedure: fac_crib Purpose: A crib on showing how to transform into field aligned coordinates Notes: $LastChangedBy: pcruce $ $LastChangedDate: 2007-09-07 16:53:14 -0700 (Fri, 07 Sep 2007) $ $LastChangedRevision: 1560 $ $URL: svn+ssh://thmsvn@ambrosia.ssl.berkeley.edu/repos/ssl_general/tags/tdas_3_00/cotrans/special/fac/fac_crib.pro $
(See ssl_general/cotrans/special/fac/fac_crib.pro)
Procedure: fac_matrix_make Purpose: generates a field aligned coordinate transformation matrix from an input B vector array(and sometimes a position vector array) then stores it in a tplot variable Arguments: mag_var_name=the name of the tplot variable storing the magnetic field vectors to be used in transformation matrix generation pos_var_name(optional)=the name of the tplot variable storing the position vectors to be used in transformation matrix generation newname(optional)=the name of the tplot variable in which to store the output error(optional) = named variable that holds the error state of the computation 1 = success 0 = failure other_dim(optional) = the second axis for the field aligned coordinate system. ************For all transformations Z = B************ valid second coord(other_dim) options: 'Xgse', translates from gse or gsm into FAC Definition(works on GSE or GSM): X Axis = on plane defined by Xgse - Z Second coordinate definition: Y = Z x X_gse Third coordinate, X completes orthogonal RHS (right hand system) triad: XYZ 'Rgeo',translate from geo into FAC using radial posision vector R_pos is radial position vector, radialy inwards. Second coordinate definition: Y = Z x Rpos Third coordinate, X completes orthogonal RHS XYZ. 'Ygeo', translate from geo into FAC using azimuthal position vector Y_pos is the azimuthal position vector, positive Westward Second coordinate definition: Y = Z x Y_pos Third coordinate, X completes orthogonal RHS XYZ 'Ysm', translate from geo into FAC using azimuthal sm position Y Axis = on plane defined by Phi_sm- Z Second coordinate definition: X = Phi_sm x Z Third completes orthogonal RHS XYZ Example: fac_matrix_make,'tha_fgs',other_dim='Xgse',pos_var_name='tha_pos',out_var_name='tha_fgs_fac_mat' Notes:--> I'm a little sparse on comments here, but I think the code should be self documenting
(See ssl_general/cotrans/special/fac/fac_matrix_make.pro)