MAGNETIC RECONNECTION IN THE EARTH'S DISTANT MAGNETOTAIL (I) STREAMING TEARING INSTABILITY
WANG SHUI ZHENG HUI-NAN(University of Science and Technology of China, Hefei 250026)
In this paper, a. magnetic reconnection proc .;.s caused by the streaming tearing instability in the earth's distant magnetotail has been studied numerically. The results show that after a brief phase of exponential growth, the growth rate of the streaming tearing instability is greatly reduced when the magnetic island width becomes comparable to the plasma sheet thickness and finally the magnetic island width saturates. The magnetic island width decreases as the magnetic Reynolds, number S increases, and it increases as the sheared flow thickness δv increases. In the case with S→∞ (η→0), the streaming tearing mode retrogrades to the streaming sausage mode in which no magnetic reconnection occurs. When the spacecraft moves across the magnetic island caused by the streaming fearing instability, the north-then-south or south-then-north Bz signatures may be observed.