Fig. 4.
Distribution of the Alfven speed A(r) and SMS wave speed C
s
(r) in the magnetotail and in the solar wind. On the resonance shells r = r
S
(points 2 and 3) and r =r
A
(points 1 and 4), the parallel phase velocity 
of a monochromatic wave is equal to, respectively, local speed C
s
of SMS waves and Alfven speed A.