Multiscale Magnetic Reconnection, Phase Transition, Particle Heating and Acceleration, and the FLARE Project

Magnetic reconnection is widely recognized as a fundamental plasma process underlying many explosive and energetic phenomena observed throughout the Universe and laboratory fusion plasmas (Ji & Daughton 2011, Ji+ 2022). Here we summarize our recent progress. A thermodynamic phase transition from collisional Sweet-Parker reconnection to collisionless Hall reconnection has been identified (Jara-Almonte & Ji 2021). The phase transition occurs when the reconnection electric field reaches Dreicer electric field reduced by the square root of the ion-to-electron mass ratio including pair plasmas. Statistical properties of multiscale magnetotail reconnection have been studied by using MMS data and machine learning techniques are being developed (Bergstedt+2020, this meeting). Guide field effects on MHD plasmoids distributions and particle acceleration by large plasmoids are studied (Majeski+2021, this meeting). In MRX, ion heating and flow generation have been measured during guide field reconnection (Goodman+2021,2022). Electron acceleration, ion and electron acoustic bursts during low-beta reconnection by laser-powered capacitor coils have been detected (Chien+2022, Zhang+2022). The upcoming FLARE (Ji+2018) will study multiscale physics, reconnection onset and particle acceleration.