Very Fast Inversion for the Stokes Vector (VFISV)
This inversion code was originally developed between 2004-2010 in order to analyse data from the Helioseismic and Magnetic Imager (HMI) instrument on-board the Solar Dynamics observatory (SDO). HMI is a Michelson-type instrument with Lyot elements to perform the wavelength tunning. Up to date, VFISV has successfully produced almost 1.5 million maps of the magnetic field vector on the solar surface using HMI data with a cadence of a map every 12 minutes. At a later stage, the code was adapted to analyse data from spectrograph-type (i.e. spectropolarimeters) instruments as well as for Fabry-Perot-type instruments. The code is also being employed for quick-look analysis of GRIS data at KIS Science Data Centre.
VFISV focuses on speed and therefore it is a Milne-Eddington (M-E) inversion code. M-E codes retrieve the average kinetic and magnetic properties of the solar atmosphere over the region in which the analysed spectral lines are formed. More information about VFISV can be found here. The code is currenly being maintained by Dr. J. M. Borrero. This inversion code is free and open-software licensed under the GPL2 licence. There are currently two different versions available, one for Fabry-Perot instruments and another for spectrograph instruments. Both can be downloaded, along with an user-manual, from:
The distributed VFISV includes also data samples and configuration files of several well-known instruments such as Hinode/SP, GRIS/GREGOR and CRISP/SST so the user can test the inversions on them.
Note: If you use VFISV in your work/research, we kindly ask that you cite the original paper: Borrero et al. (2011), Sol.Phys, 273, 267