Evolution of Elemental Abundances during B-Class Solar Flares: Soft X-Ray Spectral Measurements with Chandrayaan-2 XSM

This cartoon links soft X-ray spectroscopy of very weak flare events with systematic changes of elemental abunances. Essentially, the impulsive phase of the flare ejects un-fractionated chromospheric material into magnetic loops, and then a fractionation process intrinsic to the hot, dense plasma generates the FIP bias that distinguishes coronal elemental abundances from photospheric ones. This new result comes from simple Sun-as-a-star soft X-ray spectroscopy with sufficient sensitivity and spectral resolution to document the process cleanly for the first time. Note that this cartoon invokes Alfvén wave transport.

     Note that this cartoon adheres to the CSHKP identification of reconnection at loop top, but that the tiny flares involved in the observational work here would not have the CSHKP sine qua non of a coronal current sheet to support the process.