Large Bi-Polar Signature in a Perpendicular Electric Field of Two-Dimensional Electrostatic Solitary Waves Associated with Magnetic Reconnection:Statistics and Discussion

【摘要】 More than 300 electrostatic solitary waves（ESWs）with a large perpendicular component which is a bi-polar waveform structure are observed in the boundary layer within the magnetic reconnection diffusion region in the near-Earth magnetotail.Such ESWs are called two-dimensional ESWs.A Singe-reconnection-based-statistical study of two-dimensional ESWs shows that:（1）ESWs can be continuously observed in the plasma sheet boundary layer（PSBL）associated with the magnetic reconnection diffusion region,and their amplitude ranges are mainly from several tens to hundreds of μV/m;（2）both one-dimension-like ESWs（very small magnitude on E_⊥）and two-dimension-like ESWs（large magnitude on E_⊥,which are even comparable to that in the E_||）are observed within a small time interval;（3）within the observation time spans,more than 61%of ESWs are regarded as two-dimensional ESWs for the I_2D>20%.We discuss the bi-polar structure in E_⊥.The observation of ESWs with a large bi-polar structure in the perpendicular electric field gives evidence that the unique waveform differs from previous understanding from observations and simulations which suggests that it should be a uni-polar waveform structure in the E_⊥ of ESWs.更多还原

【Abstract】 More than 300 electrostatic solitary waves（ESWs）with a large perpendicular component which is a bi-polar waveform structure are observed in the boundary layer within the magnetic reconnection diffusion region in the near-Earth magnetotail.Such ESWs are called two-dimensional ESWs.A Singe-reconnection-based-statistical study of two-dimensional ESWs shows that:（1）ESWs can be continuously observed in the plasma sheet boundary layer（PSBL）associated with the magnetic reconnection diffusion region,and their amplitude ranges are mainly from several tens to hundreds of μV/m;（2）both one-dimension-like ESWs（very small magnitude on E_⊥）and two-dimension-like ESWs（large magnitude on E_⊥,which are even comparable to that in the E_||）are observed within a small time interval;（3）within the observation time spans,more than 61%of ESWs are regarded as two-dimensional ESWs for the I_2D>20%.We discuss the bi-polar structure in E_⊥.The observation of ESWs with a large bi-polar structure in the perpendicular electric field gives evidence that the unique waveform differs from previous understanding from observations and simulations which suggests that it should be a uni-polar waveform structure in the E_⊥ of ESWs.更多还原