r_value.pro
Calculate Schrijver's R value for an active region's magnetogram.
The R value quantifies the amount of unsigned magnetic flux around a strong magnetic polarity inversion line (MPILs) present in the photospheric normal-to-surface magnetic field of an active region. Original calculation of R was implemented for line-of-sight MDI magnetograms, therefore this implementation reduce the HMI magnetogram's resolution from 0.5'' to 2.0''. In this implementantion, R value can be calculated using the radial-component magnetogram provided by the CEA version of HMI data.
R_VALUE, c_img, f_meta, t_obs, th, d [,resample=resample] ,r_val=r_val]
c_img = Br or Blos HARP cutout magnetogram corrected for limb presence.
f_meta = metada associatted to image containing magnetogram's resolution.
t_obs = magnetogram's observation time
th = threshold for defining strong MPILs.
d = Gaussian FMHW value. Set at 10 pixel = 15 Mm.
resample = resample HMI magnetogram to MDI resolution of 2''.
Value of magnetic flux threshold (th) in order to define the strong portion of MPILs. Different values of th are used for Blos or Br.
r_val = Log(R) value.
r_value_blos_logr, r_value_br_logr
https://dev.flarecast.eu/stash/projects/FE/repos/rvalue-idl/browse