New HMI high-cadence vector magnetograms are now available. Observations every 135 or 90 seconds reveal the rapid magnetic evolution occurring during major solar eruptions.
The HMI data-collection scheme was changed on 13 April 2016 to reduce noise in the vector magnetic field measurement. Starting at 19:24, the Stokes data series hmi.S_720s has been computed by combining filtergrams from both HMI cameras.
A statistical study using HMI vector magnetograms predicts the fastest CME that an active region can produce based on its magnetic parameters.