Richard Feynman once said that turbulence is
the most important unsolved problem of classical physics. In ordinary
fluid one can detect turbulence in various places: when one pours cream into a coffee, in
uprising smoke, or in a fast flowing river. Turbulence in plasma is more complicated
due to the presence of a magnetic field. Plasmas can also
sustain several different wave modes that at the sufficiently small
scales can interact with the individual particles: energizing them,
causing scattering, producing anomalous resistivity and transport. In
first part of the talk I will show how Kelvin-Helmholtz
instability can generate plasma transport at the low-latitude boundary
layer by using MHD and Hall-MHD simulations. In second part of the talk
I will show evidence of mutual existence of turbulence and
discrete wave modes at the high-altitude cusp. High-altitude cusps
are extremely turbulent regions--even during quiet geomagnetic
conditions. For the first time we have been able to study this region
with multi-point 'in situ' measurements by using 4 Cluster spacecraft.
The four measurement points enable us to find gradients in a
plasma, and calculate length scales of the magnetic field
fluctuations. I will discuss the structure of the
double-sloped power law spectra with 'inertial' and 'dissipation' range
and the physical mechanism generating the spectral breakpoint--usually
observed at the local ion cyclotron frequency. I will also show
evidence of the wave particle interactions occurring in high-altitude
cusp. Finally, I will conclude with ideas for future
research, and why it is so important to understand the coupling between
MHD and kinetic scales.