FORMATION OF QUASAR CLOUDS BY THERMAL-INSTABILITY IN THE PRESENCE OF ALFVEN-WAVE HEATING

Highly perturbed magnetic field exist in quasars which will produce a large Alfven wave flux. We investigate here the effect of Alfven wave heating on the radiative heating-cooling function of broad-line emitting clouds in quasars with respect to the thermal instability. Jatenco-Pereira & Opher investigated resonance surface damping of Alfven waves in the atmospheres of young and old stars and the Sun, and we study here resonance surface damping of Alfven waves in the region of broad-line emitting clouds in quasars. The radiative heating-cooling function used depends on (1) heating and cooling associated with recombination (H(REC)); (2) radiative losses due to electron excitation of resonance transitions in metal ions (H(MI)); (3) thermal bremsstrahlung (H(BREM)); (4) Compton heating-cooling (H(COM)); and (5) Alfven wave heating (H(SW)). We find that a thermal instability can occur at the observed pressure approximately 10(-2) dynes cm-2, in particular, we find that the broad-line emission clouds of quasars can be kept in thermal equilibrium with the hot intercloud medium with Alfven wave heating in the cloud H(SW) approximately 3 x 10(-5) H(RAD), where H(RAD) is the sum of H(REC), H(MI), H(BREM), and H(COM).