Analysis Of The Energy Flux Density Near Electron Diffusion Region Of Asymmetric Magnetic Reconnection

Magnetic reconnection is a common energy release phenomenon in plasmas,which is widely present in the solar-terrestrial space environment and laboratory plasmas.Magnetic reconnection can rapidly convert the magnetic energy stored in magnetic field lines into the kinetic and thermal energy of plasma.It plays a crucial role in many space hazardous events such as solar flares,coronal mass ejections,and substorms in the Earth’s magnetosphere.In the space near the Earth,the interaction between the interplanetary magnetic field and the Earth’s dipole magnetic field results in magnetic reconnection,which provides us with an observable natural "laboratory" for studying magnetic reconnection phenomena.The magnetopause is a necessary passage for solar wind materials and energy to enter the Earth’s magnetosphere,so studying this region is crucial for us to fully understand our living space environment and conduct space weather forecasting.The Magnetospheric Multiscale satellite provides us with a large amount of high-precision magnetopause detection data,but establishing a database of magnetopause crossing events from the massive MMS data is not only a laborious task but also often results in a biased event library due to subjective factors affecting the determination criteria.Therefore,it is crucial for us to efficiently search for magnetopause crossings in massive satellite data when conducting research.On the other hand,previous observations and simulations have studied the conversion and distribution of energy in symmetric reconnection,but there has been less research on the energy conversion and distribution in asymmetric reconnection at the magnetopause.It is not clear how energy is converted and distributed between different forms of energy and different types of particles in the core diffusion region of asymmetric reconnection at the magnetopause,especially near the electron diffusion region.This paper investigates these two issues,and the research results are as follows:1.We have designed an algorithm based on the large difference in electron and ion density between the magnetosphere and magnetosheath,as well as the different distribution of electrons and ions on the energy spectrum on both sides of the magnetopause,to automatically screen magnetopause crossing events from massive MMS satellite data.2.We selected multiple magnetopause reconnection events observed by the MMS satellite passing through the electron diffusion region and analyzed their energy flux.We statistically examined the relationship between energy flux and variations in speed and magnetic field,and discussed the influence of upstream parameters on energy conversion and distribution.As a result,the following conclusions were drawn: 1)Among all events,ion enthalpy flux dominates the total energy flux,consistent with previous studies,which showed that at upstream plasma with high values,ion enthalpy flux can significantly exceed ion kinetic energy flux;2)The contributions of ion thermal flux and Poynting flux cannot be ignored in all events,but these two terms were not included in previous theoretical models;3)Near the EDR,the ion thermal flux in the L direction is anti-correlated with the ion velocity in the L direction;4)The kinetic and enthalpy fluxes of the M-directional electron flux are mainly opposite to the current direction,while those of the M-directional ion kinetic and enthalpy fluxes are mainly in the same direction as the current.We also attempted to study the relationship between upstream value and ion enthalpy flux for energy flux in reconnection.However,we found no clear relationship between them.Our multi-event analysis confirmed the universality of the anti-correlation between ion thermal flux and ion velocity,and the specific reasons behind this phenomenon require further analysis and investigation.