An analysis of unidimensional soliton gas models of magnetohydrodynamic turbulence in thf solar wind

• Autores: Dawson, S.P.; Fontán, C.F.
• Año de publicación: 1990
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: Astrophys. J. 1990;348(2):761-777
• Materia: Hydromagnetics; Sun: solar wind
• Institución: Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales

We compare two statistical models of Alfvén solitons whose evolution is described by the one-dimensional derivative nonlinear Schrödinger (DNLS) equation, contrasting their predictions with solar wind observations. Both distribution functions give the same mean number of solitons. This confirms a previous calculation of Ponce Dawson and Ferro FontÁn of the number of solitons which evolve from an arbitrary initial condition. One of the distribution functions follows an exponential law with soliton energy and the other follows a power law; the latter gives better results than the former. Within these models, we can explain the variation of the observed spectra (spectral index, outer scale, and maximum value) with the heliocentric distance. This variation is related to the radial dependence of the mean level of modulational instability in the medium. Concerning the spectral index, our calculation improves that of Ovenden, Shah, and Schwartz, because an average over the soliton phases is included.
Fil:Dawson, S.P. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.