Chaotic Phenomena in Unstable System

不稳定系统中的混沌现象

基本信息

批准号：
08458110
负责人：
KAWAI Yoshinobu
金额：
$ 1.22万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08458110/
关键词：
unstable system drift velocity period doubling intermittent chaos type-1 corelation dimension ion acoustic instability electron beam plasma instability 電子ブーム・プラズマ不安定性プラズマカオスダブルプラズマ

项目摘要

To study chaotic phenomen in unstable systems, we excited two types of instabilities by injecting an electron beam or passing a current into a Double plasma. Then, we adjusted to make the system chaotic by controlling the growth rate of the instabilities. The experiments were performed using a Double-Plasma Device. Argon gas was used and the pressure was ranged from 10^<-4> to 3*10^<-4> Torr. The Plasma parameters were : n_e= (1-5) *10^8cm_<-3> and Te=1eV.Obtained main results were as follows :[1] Electron beam plasma system :(1) By injecting an elecron beam whose energy is 10-100eV into the plasma, we excited the electron beam plasma instability whose frequency is around 200MHz.(2) When the electron beam density was increased, the period doubling appeared. The period-2 and period-3's bifurcation took place, showing that there is a window.(3) We calcurated the correlation dimension D by the embeding method and found that D=2.5 for period-3 and 3.3 for period-4, respectively.(4) The max … More imum Lyapunov exponent was positive, suggesting that the system is chaotic.(5) It is concluded from (3) (4) that the electron beam plasma system is in the chaotic state.[2] Ion acoustic instability system :(1) In order to pass a current in the plasma, we installed two grid meshes in the plasma and applied DC potentials to one of the grids. When the current exceeded a certain value, the ion acouistic instability was excited, where the upper cut off frequency was around the ion plasma frequency. The electron drift velocity was measured with the probe and amounted to 40Cs (Cs : ion acoustic velocity).(2) Above results are understood from the dispersion relation of the current-driven ion acoustic instability.(3) Observed time series showed that the system becomes intermittent chaos above a threshold. The correlation dimension was non-integer and larger than 2. The maximum Lyapunov exponent was positive, which suggests that the system is in an intemittent chaotic state.(4) The spectrum took a form of f^<-1>, so that observed intemittency is Type-1. Less

为了研究不稳定系统中的混乱现象，我们通过注入电子束或将电流传递到双等离子体中来激发两种类型的不稳定性。然后，我们通过控制不稳定性的增长率来调整以使系统混乱。实验是使用双皮压设备进行的。使用了氩气，压力范围为10^<-4>到3*10^<-4>托尔。血浆参数为：n_e =（1-5） *10^8cm _ <-3>和TE = 1ev = 1ev。取得的主要结果如下：[1]电子束等离子体系统：（1）通过将能量的能量注射为10-100EV的电束中的能量为等离子，我们激发了电子束的频率，我们的频率左右是频率左右的频率。出现了一倍。周期2和周期3的分叉发生了，表明有一个窗口。（3）我们通过嵌入方法计算了相关尺寸d，发现分别为周期-4的d = 2.5 = 2.5。（4）最大…最大…更imum lyapunov是积极的，该系统是正面的，表明了系统是chaotic is prom。混乱状态。[2]离子声学不稳定系统：（1）为了传递等离子中的电流，我们在等离子体中安装了两个网格网格，并将直流电势应用于其中一个网格。当电流超过一定值时，离子丙旋式不稳定性就会激发，在离子等离子体频率周围的上切断频率是。用探测器测量电子漂移速度，并等于40c（CS：离子声速度）。（2）从上面的结果从电流驱动的离子声不稳定性的分散关系中得知上述结果。（3）观察到的时间序列表明该系统在阈值上方的间歇性混乱。相关维度是非直接的，大于2。最大lyapunov指数为正，这表明该系统处于整数混乱状态。（4）频谱采取了一种f^<-1>的形式，因此观察到的InteNmittentent是Type-1。较少的