  We study a complex plasma under microgravity conditions that is first
stabilized with an oscillating electric field. Once the stabilization is
stopped, the so-called heartbeat instability develops. We study how the kinetic
energy spectrum changes during and after the onset of the instability and
compare with the double cascade predicted by Kraichnan and Leith for
two-dimensional turbulence. The onset of the instability manifests clearly in
the ratio of the reduced rates of cascade of energy and enstrophy and in the
power-law exponents of the energy spectra.
