Dressed Langmuir solitons

1987 ◽  
Vol 30 (9) ◽  
pp. 2703-2707 ◽  
Author(s):  
P. Deeskow ◽  
H. Schamel ◽  
N. N. Rao ◽  
M. Y. Yu ◽  
R. K. Varma ◽  
...  
Keyword(s):  
2005 ◽  
Vol 336 (1) ◽  
pp. 46-52 ◽  
Author(s):  
T.A. Davydova ◽  
A.I. Yakimenko ◽  
Yu.A. Zaliznyak
Keyword(s):  

1996 ◽  
Vol 243 (1) ◽  
pp. 195-198 ◽  
Author(s):  
G. Thejappa ◽  
R. G. Stone ◽  
M. L. Goldstein

1982 ◽  
Vol 27 (1) ◽  
pp. 95-120 ◽  
Author(s):  
N. Nagesha Rao ◽  
Ram K. Varma

A systematic and self-consistent analysis of the problem of Langmuir solitons in the entire range of Mach numbers (0 < M < 1) has been presented. A coupled set of nonlinear equations for the amplitude of the modulated, high-frequency Langmuir waves and the associated low-frequency ion waves is derived without using the charge neutrality condition or any a priori ordering schemes. A technique has been developed for obtaining analytic solutions of these equations where any arbitrary degree of ion nonlinearity consistent with the nonlinearity retained in the Langmuir field can be taken into account self-consistently. A class of solutions with non-zero Langmuir field intensity at the centre (ξ = 0) are found for intermediate values of the Mach number. Using these solutions, a smooth transition from single-hump solitons to the double-hump solitons with respect to the Mach number has been established through the definitions of critical and cut-off Mach numbers. Further, under appropriate limiting conditions, various solutions discussed by other authors are obtained. Sagdeev potential analyses of the solutions for the Langmuir field as well as the ion field are carried out. These analyses confirm the transition from single-hump solitons to the double-hump solitons with respect to the Mach number. The existence of many-hump solitons for higher-order nonlinearities in the low-frequency ion wave potential has been conjectured. The method of solution developed here can be applied to similar equations in other fields.


1977 ◽  
Vol 20 (5) ◽  
pp. 750 ◽  
Author(s):  
N. R. Pereira
Keyword(s):  

1999 ◽  
Vol 104 (A4) ◽  
pp. 6751-6757 ◽  
Author(s):  
Paul J. Kellogg ◽  
Keith Goetz ◽  
Steven J. Monson ◽  
Stuart D. Bale
Keyword(s):  

2003 ◽  
Vol 69 (3) ◽  
pp. 199-210 ◽  
Author(s):  
J. F. McKENZIE

We investigate the conditions under which ‘high-frequency’ electron acoustic–Langmuir solitons can be constructed in a plasma consisting of protons and two electron populations: one ‘cold’ and the other ‘hot’. Conservation of total momentum can be cast as a structure equation either for the ‘cold’ or ‘hot’ electron flow speed in a stationary wave using the Bernoulli energy equations for each species. The linearized version of the governing equations gives the dispersion equation for the stationary waves of the system, from which follows the necessary – but not sufficient – conditions for the existence of soliton structures; namely that the wave speed must be less than the acoustic speed of the ‘hot’ electron component and greater than the low-frequency compound acoustic speed of the two electron populations. In this wave speed regime linear waves are ‘evanescent’, giving rise to the exponential growth or decay, which readily can give rise to non-linear effects that may balance dispersion and allow soliton formation. In general the ‘hot’ component must be more abundant than the ‘cold’ one and the wave is characterized by a compression of the ‘cold’ component and an expansion in the ‘hot’ component necessitating a potential dip. Both components are driven towards their sonic points; the ‘cold’ from above and the ‘hot’ from below. It is this transonic feature which limits the amplitude of the soliton. If the ‘hot’ component is not sufficiently abundant the window for soliton formation shrinks to a narrow speed regime which is quasi-transonic relative to the ‘hot’ electron acoustic speed, and it is shown that smooth solitons cannot be constructed. In the special case of a very cold electron population (i.e. ‘highly supersonic’) and the other population being very hot (i.e. ‘highly subsonic’) with adiabatic index 2, the structure equation simplifies and can be integrated in terms of elementary transcendental functions that provide the fully non-linear counterpart to the weakly non-linear sech$^{2}$-type solitons. In this case the limiting soliton is comprised of an infinite compression in the cold component, a weak rarefaction in the ‘hot’ electrons and a modest potential dip.


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