The effects of high-frequency Alfvén waves on coronal heating and solar wind acceleration

Wave effects in a two-fluidmodel for the solar corona and wind are studied. Heating and acceleration are achieved by high-frequency Alfvén waves, which are assumed to be created through small-scale reconnections in the chromospheric network. The wave energy flux Fw is given in the model as a lower boundary condition. Waves with a power spectrum of the form P0(f/f0)−1 in the frequency range from 1 to 800 Hz and with P0 = 40× 1011 nT2/Hz and f0 = 10−5 Hz, corresponding to an integrated amplitude of 35 km/s, can heat the corona to a temperature of 106 K at r = 1.2 R , and 2.6 × 106K (the maximum) at r = 2 R , starting from 4 × 105 K at r = 1 R . Thermal and wave pressure gradients accelerate the wind to speeds of 100 km/s at r = 1.2 R , and 212 km/s at r = 2 R , starting from 2 km/s at r = 1 R in a rapidly diverging stream tube. Asymptotic wind speeds in the observed range of 700 to 800 km/s at 0.3 AU are obtained with wave amplitudes of 30 to 37 km/s in the frequency range from 1 to 30 Hz, corresponding to P0 = 90× 1011 nT2/Hz.