A Sudden Increase in Current During a Flare

Using the vector magnetic map observed by SDO (Solar Dynamic Observatory)/HMI (Helioseismic and Magnetic Imager) and the integral form of Ampere's law, this paper calculates the vertical current density during the X1.6 flare in the active area AR12205 on November 7, 2014. By analyzing the time evolution of the vertical current density on the photosphere, it is found that the current density experiences a sudden increase during the flare outbreak period, and the increased area corresponds to the radiation enhancement position of the flare double band. Then the strong current density profile is superimposed on the observation image of SDO/AIA160 nm band, it is found that the shape and distribution of current density are strongly related to the flare. These observations are consistent with the theoretical prediction of the standard three-dimensional flare model. Our research provides strong observational evidence for the three-dimensional Quasi-Separatrix Layer (QSL) magnetic reconnection model.