Galactic winds driven by cosmic rays

Cosmic rays traveling through a magnetized plasma with mean velocity greater than the Alfven speed can become coupled to the plasma by the emission of magnetohydrodynamic waves. Using a time-independent, spherically symmetric, hydrodynamic treatment, we show that cosmic rays escaping from a galaxy can carry along thermal gas and produce a ''galactic wind''. Solutions indicate that a typical galaxy can lose mass at a rate approx.1-10 M/sub sun/+yr/sup -1/ and energy at a rate approx.1040-1042 ergs/sup -1/. The possible role of galactic winds in radio and X-ray sources is explored. A model is proposed to explain the X-ray emission observed from clusters of galaxies