Falling-tone chorus: theory and simulations

Thursday, 18 December 2014
A. Rualdo Soto-chavez1, Ge Wang1, Amitava Bhattacharjee2, Guo-Yong Fu2 and Hakan M. Smith3, (1)Princeton University, Princeton, NJ, United States, (2)Princeton University, Princeton Plasma Physics Laboratory, Princeton, NJ, United States, (3)Max Planck Institute for Plasma Physics, Greifswald, Germany
During the last few years, improved observations indicate that falling-tone chorus (fallers) has characteristics that are quite different from rising-tones (risers). Among the most important characteristics that distinguish fallers from risers are: large angles of propagation and usually lower maximum amplitudes. These characteristics make fallers more difficult to simulate numerically than risers. Recently, we have developed a new model that successfully accounts for fallers. The model proposes that fallers start as a marginally unstable mode, which requires a balance between growth and damping, attributable to the Landau damping of oblique waves in this collisionless environment. The extension of the theory to risers will be discussed.