Double layers and ion-acoustic waves are investigated by using a one-dimensional electrostatic particle-in-cell simulation code. Our results show that double layers can be formed even when the drift velocity between e...Double layers and ion-acoustic waves are investigated by using a one-dimensional electrostatic particle-in-cell simulation code. Our results show that double layers can be formed even when the drift velocity between electrons and ions is less than the electron thermal velocity. Electron and ion density depressions were clearly seen. Electrons gradually developed a distribu- tion comprising both background and beam components. In fact, as the initial electron-ion drift velocity was less than the electron thermal velocity, intense ion-acoustic waves could be found only at the places where the electron beam was located, suggesting that they are excited by the self-consistently developed electron beam. Besides the Langmuir waves and ion-acoustic waves, the beam mode excited by electron beams produced in our simulation has been clearly found.展开更多
基金supported by National Natural Science Foundation of China(Nos.40974097,41204115)the Excellent Youth Foundation of Shandong Scientific Committee(No.JQ201212)CAS Key Laboratory of Basic Plasma Physics,Department of Geophysics and Planetary Science,University of Science and Technology of China
文摘Double layers and ion-acoustic waves are investigated by using a one-dimensional electrostatic particle-in-cell simulation code. Our results show that double layers can be formed even when the drift velocity between electrons and ions is less than the electron thermal velocity. Electron and ion density depressions were clearly seen. Electrons gradually developed a distribu- tion comprising both background and beam components. In fact, as the initial electron-ion drift velocity was less than the electron thermal velocity, intense ion-acoustic waves could be found only at the places where the electron beam was located, suggesting that they are excited by the self-consistently developed electron beam. Besides the Langmuir waves and ion-acoustic waves, the beam mode excited by electron beams produced in our simulation has been clearly found.
