Name: 

decay_index.pro

Purpose: 

Calculate decay index parameters using 3D magnetic field data derived from potential field extrapolation

Calling sequence:

output_di = decay_index(c_img [,binxy_di=binxy_di] [,di_heigh_range=di_heigh_range] [,binxy_mpil=binxy_mpil] [,mpil_info=mpil_info] [,mpil_xy=mpil_xy] [,crit_di=crit_di])

Input parameters:

c_img - B_los and B_r images from SDO/HMI Space-weather HMI Active Region Patch (SHARP) cylindrical equal area (CEA) near-realtime (NRT) data

Optional Input Keyword Parameters:

binxy_di - number for xy spatial binning of sharp magnetic field input data related to decay index calculation [pixels] ; default=4

di_heigh_range - height range (MIN, MAX) for parameterising decay index [Mm] ; default=[10,50]

binxy_mpil - number for xy spatial binning of sharp magnetic field input data related to magnetic polarity inversion line (MPIL) detection [pixels] ; default=1

crit_di - critical decay index value ; default=1.5

mpil_info - information on magnetic polarity inversion lines (MPILs)

mpil_xy - x and y coordinates of MPILs [pixels]

Optional Output Keyword Parameters:  

Output parameters:

output_di - 4 element 1D array related to decay index parameters     

                  output_di[0]: ratio of MPIL length to h_min for the SMPIL segment with the lowest h_min        

                  output_di[1]: ratio of MPIL length to h_min for the strong MPIL (SMPIL) segment with the longest SMPIL,

                                       where h_min is the minimum height at which decay index above the rectangle enclosing each of SMPILs is greater than the critical decay index value                  

                  output_di[2]: maximum ratio of MPIL length to h_min from all SMPIL segments

                  output_di[3]: sum of ratios of MPIL length to h_min from all SMPIL segments

Property name in DB:

decay_index_blos.l_over_min_hmin, decay_index_blos.lmax_over_hmin, decay_index_blos.max_l_over_hmin, decay_index_blos.tot_l_over_hmin,

decay_index_br.l_over_min_hmin, decay_index_br.lmax_over_hmin, decay_index_br.max_l_over_hmin, decay_index_br.tot_l_over_hmin

Repository

https://dev.flarecast.eu/stash/projects/FE/repos/decay_index-idl/browse

References