Reflection Coefficient and Non-WKB Effects for Alfvén Waves Propagating in the Solar Wind

The propagation of Alfvén waves in spherically symmetric, isothermal solar wind models with two different temperatures T0=2.85×106 K and T0=8.2×105 K is considered. The steady-state Alfvén wave equations are solved numerically and the resulting reflection coefficient and non-WKB effects are calculated. The obtained results show that the reflection coefficient is practically zero in the high-temperature wind model, where wave reflection and non-WKB effects are essentially absent, and that it can also be zero in the low-temperature model, where wave reflection and non-WKB effects are present. A physical explanation of these results is given.