Generation of Kinetic Alfven Waves in the Magnetotail *

Shear Alfven mode waves, including kinetic Alfven waves (KAWs), are often observed around in the tail plasma sheet around fast flows, and they are believed to play important roles in powering the low-altitude auroral acceleration.In this talk, we use the Auburn Global Hybrid Code in 3-D (ANGIE3D) to investigate the generation and propagation of shear Alfven waves in the magnetotail. Our results show that shear Alfven waves/KAWs are generated in magnetic reconnection and present around fast flows. The KAWs are identified, and the Alfvenic energy spectrum is examined. As these waves propagate toward the ionosphere carrying the field-aligned currents and Poynting flux, the flow braking region in front of the strong dipolar magnetic field significantly alters their structure and thus the precipitating Alfvenic energy flux. The subsequent generation of shear Alfven waves in the dipole-like field region of the magnetosphere is also discussed.