Abstract
Abstract. Arbitrary amplitude electron acoustic solitons are studied in an unmagnetized plasma having cold electrons and ions, superthermal hot electrons and an electron beam. Using the Sagdeev pseudo potential method, theoretical analysis is carried out by assuming superthermal hot electrons having kappa distribution. The results show that inclusion of an electron beam alters the minimum value of spectral index, κ, of the superthermal electron distribution and Mach number for which electron-acoustic solitons can exist and also changes their width and electric field amplitude. For the auroral region parameters, the maximum electric field amplitudes and soliton widths are found in the range ~(30–524) mV m−1 and ~(329–729) m, respectively, for fixed Mach number M = 1.1 and for electron beam speed of (660–1990) km s−1.
Highlights
Electron acoustic mode can exist in a plasma having two electron components, hot and cold, and it propagates at a speed close to the electron-acoustic speed
Lakhina et al (2009, 2011) proposed a model based on electronacoustic solitons and double layers in a four-component plasma system consisting of core electrons, two counter streaming electron beams, and one type of ions, to explain the electrostatic solitary waves observed by CLUSTER satellite in the magnetosheath region (Pickett et al, 2005)
We have studied electron-acoustic solitons in four component plasma consisting of cold electrons and ions, hot superthermal electrons and an electron beam
Summary
Electron acoustic mode can exist in a plasma having two electron components, hot and cold, and it propagates at a speed close to the electron-acoustic speed. S. Devanandhan et al.: Electron acoustic solitons in the presence of an electron beam amplitude electron-acoustic solitary potentials in a plasma having stationary ions, cold inertial electrons and hot superthermal electrons. Devanandhan et al.: Electron acoustic solitons in the presence of an electron beam amplitude electron-acoustic solitary potentials in a plasma having stationary ions, cold inertial electrons and hot superthermal electrons They found that as spectral index κ decreases, soliton amplitude increases while its width narrows down. Sahu (2010) studied the existence of small amplitude electron-acoustic double layers in an unmagnetized plasma in a theoretical model similar to Younsi et al (2010) Both the above studies did not include the effect of cold electron temperature and mobile ions.
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