Vd = -0.4Vth Vdi = 0.3Vth

Ion density (a)

charge density (b)

electric field (c)

electrostatic potential (d)

ion phase space (e)

These figures show snapshots of run? at T=3000.  (a) ion density profile (b) charge

density profile (c) electric field profile (d) electrostatic potential profile

(e) ion phase space plot



In this case, type 2 weak double layers formed clearly.  Large amplitude ion acoustic

solitary waves propagate upward and cause a rarefaction of hot ions in the downstream

 region of the waves.  Three type 2 weak double layers exist in this simulation system.


The upward hot ion beam gives its energy to the ion acoustic wave fast mode, which is

damped in two component model, and these waves grow to be solitary waves.  If these 

solitary waves have enough amplitude to trap particles of the upward ion beam, the form

 of solitary wave steepn and growth of the solitary wave finish.  Becouse such waves
 
affects the ion beam as potential barrier, reflections of ions occur in both side of

 the wave.