Abstract
Large nonlinear acoustic waves are discussed in a plasma made up of cold supersonic and adiabatic subsonic positive ions, in the presence of hot isothermal electrons, with the help of Sagdeev pseudopotential theory. In this model, no solitons are found at the acoustic speed, and no compositional parameter ranges exist where solutions of opposite polarities can coexist. All nonlinear modes are thus super-acoustic, but polarity changes are possible. The upper limits on admissible structure velocities come from different physical arguments, in a strict order when the fractional cool ion density is increased: infinite cold ion compression, warm ion sonic point, positive double layers, negative double layers, and finally, positive double layers again. However, not all ranges exist for all mass and temperature ratios. Whereas the cold and warm ion sonic point limitations are always present over a wide range of mass and temperature ratios, and thus positive polarity solutions can easily be obtained, double layers have a more restricted existence range, specially if polarity changes are sought.
Original language | English |
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Article number | 042309 |
Journal | Physics of Plasmas |
Volume | 18 |
Issue number | 4 |
DOIs | |
State | Published - Apr 2011 |
Externally published | Yes |
Funding
M.A.H. thanks the National Research Foundation for research grants. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and therefore the NRF does not accept any liability in regard thereto. I.K. acknowledges the UK EPSRC (Engineering and Physical Science Research Council) for support through S&I Grant No. EP/D06337X/1 to Centre for Plasma Physics, Queen’s University Belfast.
Funders | Funder number |
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Engineering and Physical Sciences Research Council | EP/D06337X/1 |
Queen's University Belfast | |
National Research Foundation of Korea |