Earth Planets Space, Vol. 59 (No. 4), pp. e13-e16, 2007E-LETTER
Yasuhiro Nariyuki and Tohru Hada
E.S.S.T., Kyushu University, Japan
(Received December 4, 2006; Revised January 10, 2007; Accepted January 16, 2007; Online published March 28, 2007)
Numerical experiments for parametric instabilities of incoherent Alfvén waves in the context of one dimensional Hall-MHD equation sets are studied. The reason why the decay instability of incoherent waves can be explained in terms of that of the coherent wave is understood through analysis on nonlinearly driven finite amplitude density fluctuations. Numerical results suggest the importance of modulational instabilities of left-hand polarized Alfvén waves.
Key words: Alfvén waves, solar wind.