Solar wind heating by heat conduction driven ion acoustic instability

Nonlinear saturation of the ion acoustic instability, driven by finite heat conduction in the solar wind, via resonance broadening is considered. The calculations based on the Hartle and Sturrock model show that this process can heat ions faster than the electrons, thereby, leading to the reduction in electron to proton temperature ratio. The difficulty with this process is that it increases the electron temperature above the value predicted by the Hartle and Sturrock model. (Auth.)