Polarization Plot

From a pair of (R+L) and (R-L) images of 17 GHz, distribution of circluar polarization degree can be obtained. It is used for judging the emission mechanism and/or deriving the magnetic field strength. The definition is;

$$r_{c} \equiv {F_{\nu}^{(R-L)}\over F_{\nu}^{(R+L)}} = {T_{b}^{(R-L)}\over T_{b}^{(R+L)}}$$

Minimum is -1 (perfectly left-handed circular polarized), and maximum is +1 (perfectly right-handed circular polarized). The procedure is :
IDL> file='./ips990828_005642' $<$CR$>$
IDL> norh_rd_img,file,indexs,datas $<$CR$>$
IDL> fi17=norh_tb2flux(dataa,indexa,/intensity) $<$CR$>$
IDL> fv17=norh_tb2flux(datas,indexs,/intensity) $<$CR$>$
IDL> norh_polariz,indexa,fi17,indexs,fv17,indexp,pol,mvdp $<$CR$>$
pol is an array of $r_{c}$. mvdp is an array including the values of unity (1) for valid data or zero (0) for non-valid data. indexp is an index correspoinding to data pol. For easy plot (Fig 3)
IDL> norh_plot,indexa,dataa,indexp,pol,mvdp $<$CR$>$
For preparing to overplot with other instrumental data, change the data format to SolarSoftware map.
IDL> norh_index2map,indexp,pol*mvdp,mappol $<$CR$>$
IDL> plot_map,mappol,/cont,levels=[-0.8,-0.4,-0.2,0.2,0.4,0.8] $<$CR$>$