Arbitrary amplitude electron-acoustic solitary waves in the presence of excess superthermal electrons

作者：Younsi Smain; Tribeche Mouloud^*

来源：Astrophysics and Space Science, 2010, 330(2): 295-300.

DOI：10.1007/s10509-010-0404-0

• Electron-acoustic waves
• Solitary waves
• Pseudo-potential analysis
• Superthermal electrons
• Plasma sheet boundary layer

The problem of arbitrary amplitude electron-acoustic solitary (EAS) waves in a plasma having cold fluid electrons, hot superthermal electrons and stationary ions is addressed. The domain of their allowable Mach numbers enlarges as the spectral index kappa increases revealing therefore that the "maxwellisation" process of the hot component favors the propagation of the EAS waves. As the superthermal character of the plasma is increased, the potential pulse amplitude increases while its width is narrowed, i.e, the superthermal effects makes the electron-acoustic solitary structure more spiky. As the spectral index kappa decreases, the hot electrons are locally expelled and pushed out of the region of the soliton's localization. A decrease of the fractional number density of the hot electrons relative to that of the cold ones number density would lead to an increase of the depth as well as the width of the localized EAS wave. Our results should help to understand the salient features of large amplitude localized structures that may occur in the plasma sheet boundary layer and may provide an explanation for the strong spiky waveforms that have been observed in auroral electric fields.

• 出版日期2010-12