[Previous] | [Session 48] | [Next]
P. Truitt (Gordon Coll. & Maria Mitchell Obs.), V. Strelnitski (Maria Mitchell Obs.)
Many strong flares of H2O masers in regions of star formation demonstrate a power-law dependence between linewidth and intensity. Several mechanisms proposed to explain this dependence are subject to severe criticism. We reassess the idea of V. Letokhov that the steep narrowing of these lines with increasing intensity is due to the transition from the regime of one-pass amplification to multi-pass amplification (oscillations) in a medium with a positive feedback. We demonstrate that the time scale of the intensity and linewidth variations which follows from previous treatments of this model is several orders of magnitude smaller than observed. We propose that this difficulty of the theory can be overcome if the effect of critical slowing down during the phase transition to oscillations is taken into account. Possible re-formulation of the theory including this effect and preliminary results of numerical modeling will be discussed. This project was partially supported by the NSF/REU grant AST-9820555.