Documentation.
Name:
r_value.pro
Purpose:
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.
Calling sequence:
R_VALUE, c_img, f_meta, t_obs, th, d [,resample=resample] ,r_val=r_val]
Input parameter:
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''.
Optional parameters:
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.
Output:
r_val = Log(R) value.
Property name in DB:
r_value_blos_logr, r_value_br_logr
Repository:
https://dev.flarecast.eu/stash/projects/FE/repos/rvalue-idl/browse