Space Physics Seminar winter-2023
High-frequency electrostatic waves driven by electron crescents in electron diffusion regions
Jan. 27, 2023,
3:30 p.m. - 5:30 p.m.
National Space Science Center, Chinese Academy of Sciences
Magnetic reconnection is a fundamental and universal process, which transfers energy stored in the magnetic field to kinetic and thermal energies of charged particles. NASA’s Magnetospheric Multiscale (MMS) mission was designed to investigate the electron-scale physics of reconnection in the Earth’s magnetosphere. The four MMS spacecraft have encountered tens of electron diffusion regions (EDRs) at the magnetopause and in the magnetotail, and various types of plasma waves, including lower-hybrid and whistler waves, have been reported in and near EDRs. Recent studies reveal that two types of high-frequency electrostatic waves (upper-hybrid waves and electron Bernstein waves) can be driven by the crescent-shaped agyrotropic electron distribution functions in several EDR events. The large-amplitude electrostatic waves can thermalize electrons and change the electron pressure tensor. Therefore, the electrostatic waves have capability to modify the balance of reconnection electric field and have feedback on the reconnection process.