Abstract:
We examine the characteristics of large amplitude slow electron-acoustic solitons supported in a
four-component unmagnetised plasma composed of cool, warm, hot electrons, and cool ions. The
inertia and pressure for all the species in this plasma system are retained by assuming that they are
adiabatic fluids. Our findings reveal that both positive and negative potential slow electron-acoustic
solitons are supported in the four-component plasma system. The polarity switch of the slow
electron-acoustic solitons is determined by the number densities of the cool and warm electrons.
Negative potential solitons, which are limited by the cool and warm electron number densities
becoming unreal and the occurrence of negative potential double layers, are found for low values
of the cool electron density, while the positive potential solitons occurring for large values of the
cool electron density are only limited by positive potential double layers. Both the lower and upper
Mach numbers for the slow electron-acoustic solitons are computed and discussed.
