FORCtool: An online service for rapid analysis of first-order reversal curve (FORC) data

The first-order reversal curve (FORC) analysis has been widely used in rock magnetism, physics, material science, biomedicine, and other fields, to characterize magnetic hysteresis properties and magnetic interactions in natural and synthetic materials. Modern software tools for processing FORC data into density distribution diagrams utilize the VARIFORC (variable FORC smoothing) algorithm, which utilizes several parameters to optimize smoothing by creating non-regularly distributed smoothing values over different regions of the FORC distribution. Manual selection of the VARIFORC parameters, however, may be a challenging task, especially when no a priori information about the magnetic make-up is available. To automatize the selection process, a recently developed FORCsensei software (Heslop et al., 2020) utilizes a machine learning approach to determine the optimal parameters and to construct maximally informative FORC diagrams. This powerful tool, however, is compute-intensive and calculation durations may be inconveniently long (using both personal computer and cloud-based services). Here, we present FORCtool, a new online service for FORC analyses. While it uses the same approach as FORCsensei, the service has extended functionality with a number of additional tools for detailed FORC analysis and offers a convenient intuitive interface. Importantly, the efficiency and speed of the analysis have been substantially increased by optimizing the calculation process and using a general-purpose graphics processing unit. In addition, FORCtool supports an extended list of data formats and includes tools for pre-processing analysis, unit converter, visualizing results, and other advanced processing options.