Nonlinear Waves in a Finite Plasma

有限等离子体中的非线性波

• 批准号: 63580013
• 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 General Scientific Research (C)
• 财政年份: 1988
• 资助国家: 日本
• 起止时间: 1988 至 1990
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-63580013/
• 关键词: Finite Plasma; Ion Acoustic Wave; Reflection Coefficient; Double Plasma; Ion-Ion Instability; Electron Beam-Plasma System; Beam Mode; Subharmonics; イオン波の反射; イオン・イオン不安定性; ポンプ波; ビ-ム・ラングミュアモ-ド; 定常シ-ス; ソリトン; イオンシース

We have studied both theoretically and experimentally nonlinear phenomena in a finite plasma without magnetic fields, and the following results are obtained.1. We examined the characteristics of the ion acoustic wave reflected by the boundary. The main results are as follows :(i) The particles trapped in the sheath formed around a negatively biased grid play an important role in the wave reflection.(ii) When an ion acoustic solution propagates into the sheath, the reflected wave becomes a solution for the large amplitude, and an ion acoustic wave for the small amplitude, respectively.(iii) The experiments on the reflection of ion waves are carried out using the DP machine. It is found that ions play an important role in the reflection, and the reflection coefficient does not depend on the frequency for the beam modes and it is decreasing function of frequency for the ion acousti wave.2. We attempted the suppression of the ion-ion instability by an external field and found that the threshold value at which the instability is suppressed depends on the frequency of the external field.3. We observed the mode transition of the electron beam-plasma instability : from the beam mode to the beam Langmuir mode.4. We succeeded in the excitation of the subharmonics of the beam mode. The subharmonics may be excited by period doubling.These results will contribute to the development of nonlinear phenomena in plasmas.

我们从理论和实验两方面研究了无磁场有限等离子体中的非线性现象，得到了如下结果.我们研究了离子声波在边界上的反射特性。主要结果如下：（1）在负偏压栅网周围形成的鞘层中，俘获的粒子对波的反射起着重要的作用。(ii)当离子声溶液传播到鞘层中时，反射波分别变为大振幅的溶液和小振幅的离子声波。(iii)利用DP机进行了离子波反射实验。研究发现，离子在反射中起着重要作用，对于离子束模式，反射系数不依赖于频率，对于离子声波，反射系数是频率的减函数.我们尝试用外场抑制离子-离子不稳定性，发现抑制不稳定性的阈值依赖于外场的频率.我们观察到了电子束-等离子体不稳定性的模式转变：从电子束模式到电子束朗缪尔模式.我们成功地激发了光束模式的次谐波。这些结果将有助于等离子体中非线性现象的发展。

项目成果

Shunichi NODA.: Jpn.J.AppI.Phys.27. 1562-1563 (1988)

野田俊一：Jpn.J.AppI.Phys.27。

Takashi SATO: "SeHーFocusimg of Iom wave in plasma with Negative Ion" J.Phys.Soc.Jpn.59. 159-165 (1990)

Takashi SATO：“负离子等离子体中 Iom 波的 SeH-Focusimg”J.Phys.Soc.Jpn.59 (1990)。

Takashi SATO: "SelfーFocusing of Ion Wave in Plasma with Negative Ion" J.Phys.Soc.Jpn.59. 159-165 (1990)

Takashi SATO：“负离子等离子体中离子波的自聚焦”J.Phys.Soc.Jpn.59 (1990)。

Toshirou KASUYA: "Observations of Subharmonic Waves in an Electron Beam Plasma System" J.Phys.Soc.Jpn.59. 3931-3936 (1990)

Toshirou KASUYA：“电子束等离子体系统中次谐波的观察”J.Phys.Soc.Jpn.59。

Toshirou kasuya, Masayoshi Tanaka, Akio Komori and Yoshinobu Kawai: "Observations of Subharmonic Waves in an Electron Beam Plasma System" J. Phys. Soc. Jpn.59. 3931-3936 (1990)

Toshirou kasuya、Masayoshi Tanaka、Akio Komori 和 Yoshinobu Kawai：“电子束等离子体系统中次谐波的观察”J. Phys。