Taraknath Saha

Obliquely propagating ion acoustic solitary waves in magnetized dusty plasma in the presence of nonthermal electrons

Obliquely propagating dust ion acoustic solitary waves subjected to an external magnetic field are studied using Sagdeev’s pseudopotential technique. Nonthermal distribution for electrons is considered. The pseudopotential is derived without considering the quasineutrality condition. It is obtained from the Poisson equation instead. Using Sagdeev’s technique, the ranges of parameters for which solitary waves exist are studied in detail.

ION ACOUSTIC SOLITARY WAVES AND DOUBLE LAYERS IN DENSE ELECTRON–POSITRON–ION MAGNETOPLASMA

The existence of ion acoustic solitary waves is studied in a magnetized dense electron-positron-ion plasma. The ions are described by the hydrodynamic equations, and the electron and positron are assumed to follow the Thomas–Fermi density distribution. The pseudopotential is derived directly from the basic equations including Poisson’s equation without assuming the quasineutrality condition. The effect of ion temperature on the solitary waves is studied, and the ranges of parameters for which solitary waves and double layers exist are also studied in detail using Sagdeev’s technique.

Obliquely propagating ion acoustic solitary waves and double layers in a magnetized dusty plasma with anisotropic ion pressure

Obliquely propagating dust ion acoustic solitary waves and double layers in an external magnetic field is studied by using Sagdeev’s pseudo-potential technique. Anisotropic ion pressure is considered, which is defined by applying the Chew–Goldberger–Low theory. The Sagdeev pseudo-potential is derived considering the Poisson equation instead of the charge neutrality condition so that the length scales of the solitary waves and double layers may be shorter than the Debye length. The ranges of parameters for which solitary waves and double layers can exist are studied in detail.

Effect of ion temperature on ion-acoustic solitary waves in a plasma with a q-nonextensive electron velocity distribution

The effect of ion temperature on the existence of arbitrary amplitude ion-acoustic solitary waves is studied in a two component plasma in presence of a q-nonextensive velocity distributed electrons by using Sagdeevs pseudo potential technique. The range of relevent parameters for which solitons may exist is discussed. It is observed that both q, the nonextensive parameter and the ion temperature σ, play significant roles in the formation and existence of solitons.

Large amplitude double-layers in a dusty plasma with a q-nonextensive electron velocity distribution and two-temperature isothermal ions

Arbitrary amplitude dust-acoustic (DA) double-layers in a plasma with nonextensive electrons, two-temperature thermal ions, and warm drifting dust grains are addressed. It is shown that DA double-layer structures, the onset of which depends sensitively on the plasma parameters, can exist. In particular, it may be noted that the electron nonextensivity may affect drastically the existence of these localized structures. In view of recent observation, our results should assist in the interpretation of the nonlinear double-layers observed in the downward current region of the aurora.

Effect of ion temperature on oblique propagation of large amplitude solitary kinetic Alfvén waves

The effect of ion temperature on the existence of large amplitude solitary kinetic Alfven waves and double layers are investigated in a two-fluid model using Sagdeev’s pseudopotential technique. The ion temperature, obliqueness parameter, and the ratio of cyclotron frequency to ion frequency are found to play significant roles in the formation and the shape of solitary kinetic Alfven waves and double layers. Hump-type solitary waves and dip-type double layers are also observed. Conditions for the existence of solitary waves and double layers are discussed.

Solitary waves and double layers in dense magnetoplasma

Using Sagdeev’s pseudopotential technique, ion acoustic solitary waves and double layers are studied subject to an external magnetic field in a two-component dense magnetoplasma consisting of ions and degenerate electrons. The ions are described by the hydrodynamic equations, and the electrons are assumed to follow the Thomas–Fermi density distribution. The pseudopotential is derived directly from Poisson’s equation without assuming the quasineutrality condition. The ranges of parameters for which solitary waves and double layers exist are studied in detail using Sagdeev’s technique.

Nonlinear Ion Acoustic Waves in a Magnetized Dusty Plasma in the Presence of Nonthermal Electrons

The Kadomtsev-Petviashili (KP) equation is derived for weakly nonlinear ion acoustic waves in a magnetized dusty plasma in the presence of nonthermal electrons. Soliton solutions are obtained in both the one-dimensional and two-dimensional framework. For the one-dimensional soliton solution the ‘tanh’ method is considered while the two-dimensional solution is obtained by a method introduced by S.V. Manacov et al., Phys. Lett. A 63, 205 (1977). It is found that in case of the onedimensional solution, both compressive and rarefactive solitary waves exist which could be obtained depending on the ratio of the electron and ion density. It is also seen that the nonthermal distribution of electrons has some significant effect in the shape of both the one-dimensional and two-dimensional solitary wave.