Quasilinear Wave "Reflection" Due to Proton Heating by an Imbalanced Turbulent Cascade

We investigate the quasilinear effects of the resonant wave-particle interaction under conditions of imbalanced turbulent heating in the collisionless coronal hole. We find that velocity-space transport of protons from the heated part of the distribution leads to strong wave growth in the minority (sunward) direction. In the present quasilinear analysis, the “reflected” waves grow to unphysical levels, indicating the necessity of including nonlinear processes. This mechanism is likely to be important in development of the fast solar wind, and may explain the puzzling minor ion observations of Landi & Cranmer (2009).