Stimulated Brillouin scattering in ionospheric modification

The stimulated Brillouin scattering (SBS) in ionospheric modification by high power HF radio waves is studied. Based on momentum and energy conservation equations and dispersion relations, the SBS matching conditions are given briefly. The variations of frequencies of ion acoustic (IA) and electrostatic ion cyclotron (EIC) stimulated by SBS are calculated with different parameters including altitudes, heating frequency, the direction of pumping wave and electron temperature at perturbed region. The different of IA and EIC frequency between low and high latitude are compared taking Hainan and HAARP as examples. The simulation results show that: the stimulated electrostatic low frequency increases as the latitude increases; the frequency of EIC changes less than IA with the variation of heating frequency, the direction of pumping wave and electron temperature at perturbed region; along with increased pump frequency, the IA frequency at high latitude increases, but at low latitude the IA frequency almost keep constant; as the direction of pump wave changes from south to north, the IA frequency in Hainan decreases, but in HAARP it increases until the geomagnetic direction, and the EIC frequency is reverse; the increased electron temperature will increase IA and EIC frequency. These results provide support for our future experiments.