  Turbulence in astrophysical and space plasmas is dominated by the nonlinear
interaction of counterpropagating Alfven waves. Most Alfven wave turbulence
theories have been based on ideal plasma models, such as incompressible MHD,
for Alfven waves at large scales. However, in the inertial Alfven wave regime
(vA > vthe), relevant to magnetospheric plasmas, how the turbulent nonlinear
interactions are modified by the dispersive nature of the waves remains to be
explored. Here we present the first laboratory evidence of the nonlinear
interaction in the inertial regime. A comparison is made with the theory for
MHD Alfven waves.
