A Sudden Increase Of Current During The Flare Outbreak Period

Solar flares are one of the most violent phenomena occurring in the solar atmosphere.Since the first solar flare was observed in 1859,the study of solar flares has been the main subject of solar physics.The eruption process of solar flares usually lasts for tens of minutes,and up to10 ³²ergenergy is released in just a few minutes.It is generally believed that the energy source of flares comes from the free magnetic field energy in the active region.The existence of free magnetic field means that the magnetic field in the active region is non-potential,which means that there is electric current.Long-term studies have shown that the electric current in the active region is closely related to the flare eruption.On November 7,2014,an X1.6 flare erupted over active region AR12205.Based on SDO/HMI,using Ampere's law in integral form,we calculate the vertical current density distribution during the flare.After analyzing the evolution characteristics of the vertical current density distribution over time,it is found that the current intensity increases significantly and rapidly during the flare eruption,and the increased region corresponds to the enhanced radiation position of the flare double zone.The profile of the strong current density is superimposed on the SDO/AIA1600 A observation image.It is found that the morphology and distribution of the current density are strongly correlated with the flare.These observations are in agreement with the theoretical predictions of the three-dimensional standard flare model.This provides strong observational evidence for the Quasi-Separatrix Layer(QSL)reconnection model.In this paper,the first part is the introduction,mainly introduces the structure of the sun and the sun's activity.The second part mainly introduces the flares,including its characteristics observed,magnetic field in the active region of the flare,flare initiation and energy release and flare theory model.The third part introduces the calculation method of current in active region.The fourth part is the main work of this paper,which is to find out the reason of the current change during a flare.The last part is summary and prospect.