Oohara W, Kuwabara Y, Hatakeyama R
Department of Electronic Engineering, Tohoku University, Sendai 980-8579, Japan.
Phys Rev E Stat Nonlin Soft Matter Phys. 2007 May;75(5 Pt 2):056403. doi: 10.1103/PhysRevE.75.056403. Epub 2007 May 9.
A pair-ion plasma without electrons consisting of C60+ and C60- is generated through the processes of electron-impact ionization, electron attachment, and magnetic filtering. Properties of electrostatic modes propagating along magnetic-field lines are experimentally investigated by externally exciting them with two types of electrodes. It is found that four kinds of wave modes exist and a frequency spectrum of phase lag between the density fluctuations of C60+ and C60- is unique in comparison with ordinary electron-ion plasmas. One of the modes is an ion acoustic wave which is divided into two branches at around the ion cyclotron frequency in the presence of a backwardlike mode joining them. The phase lag of the ion acoustic wave strongly depends on the frequency, while those for the other ion plasma and intermediate-frequency waves are constant at pi independent of the frequency.
通过电子碰撞电离、电子附着和磁过滤过程产生了一种由C60⁺和C60⁻组成的无电子对离子等离子体。通过用两种类型的电极对沿磁力线传播的静电模式进行外部激发，对其特性进行了实验研究。结果发现存在四种波模式，并且与普通电子 - 离子等离子体相比，C60⁺和C60⁻密度涨落之间的相位滞后频谱是独特的。其中一种模式是离子声波，在存在连接它们的类反向模式的情况下，该离子声波在离子回旋频率附近分为两个分支。离子声波的相位滞后强烈依赖于频率，而其他离子等离子体波和中频波的相位滞后在π处恒定，与频率无关。
