It was shown by dos Santos et al. the importance of Alfv\'en waves to explainthe winds of Wolf-Rayet stars. We investigate here the possible importance ofAlfv\'en waves in the creation of inhomogeneities in the winds of early-typestars. The observed infrared emission (at the base of the wind) of early-typestars is often larger than expected. The clumping explains this characteristicin the wind, increasing the mean density and hence the emission measure, makingpossible to understand the observed infrared, as well as the observedenhancement in the blue wing of the $H_\alpha$ line. In this study, weinvestigate the formation of these clumps a via thermal instability. Theheat-loss function used, $H(T,n)$, includes physical processes such as:emission of (continuous and line) recombination radiation; resonance lineemission excited by electron collisions; thermal bremsstrahlung; Comptonheating and cooling; and damping of Alfv\'en waves. As a result of thisheat-loss function we show the existence of two stable equilibrium regions. Thestable equilibrium region at high temperature is the diffuse medium and at lowtemperature the clumps. Using this reasonable heat-loss function, we show thatthe two stable equilibrium regions can coexist over a narrow range of pressuresdescribing the diffuse medium and the clumps.
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