TY - JOUR
T1 - Large acoustic solitons and double layers in plasmas with two positive ion species
AU - Verheest, Frank
AU - Hellberg, Manfred A.
AU - Saini, Nareshpal Singh
AU - Kourakis, Ioannis
N1 - Funding Information:
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.
PY - 2011/4
Y1 - 2011/4
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=79955684869&partnerID=8YFLogxK
U2 - 10.1063/1.3579397
DO - 10.1063/1.3579397
M3 - Article
AN - SCOPUS:79955684869
SN - 1070-664X
VL - 18
JO - Physics of Plasmas
JF - Physics of Plasmas
IS - 4
M1 - 042309
ER -