Energy Relaxation of an Ion Beam in a Turbulent Plasma

The dependence of the energy relaxation of an energetic ion beam on the correlation time of turbulent waves is studied experimentally in an ion beam-plasma system in a magnetic field. The turbulent waves are controlled by changing axial current through the plasma and their correlation times are estimated from the frequency power spectra. It is found that the broadening of the energy spectrum of the ion beam due to interaction with the ion acoustic turbulent waves is approximately proportional to the inverse square root of the correlation time. Those results are compared with a theoretical model.