一維與二維電漿靜電粒子模擬與應用

One and Two-Dimensional Electrostatic Particle Simulations and Applications

蔣步勤(Bu-Chin Chiang)

指導教授 ： 郝玲妮

國立中央大學/地球科學學院/太空科學研究所/碩士(2008年)

摘要

在太陽風與地球磁層中普遍存在著許多的靜電波與電磁波，而其中位於地球磁尾電漿片邊界層與高緯度極光發生的區域，人造衛星分別已觀測到一維與二維結構之electrostatic solitary wave (ESW)。因此，已有許多研究探討ESW之形成與特性。本文主要為發展適用於太空電漿環境之一維與二維靜電場全粒子模式，可應用於研究太空環境中之各種靜電波之發展。我們將其應用於討論帶電粒子束不穩定問題產生之靜電波結構。模擬中所使用的自由參數包括：離子束之熱速度、電子束之粒子數量、離子與電子之質量比、電子迴旋頻率與電子振盪頻率比。我們分析各種參數對ESW形成之影響，並討論在一維與二維系統中非線性發展所產生之結構上的差異。

關鍵字

靜電粒子模擬

並列摘要

The existence of electrostatic and electromagnetic waves is common in the solar wind and Earth’s magnetosphere. Satellite observations have shown that the electrostatic solitary wave (ESW) exhibits one-dimensional structures in the plasma sheet boundary and two-dimensional structures in the auroral regions. Studies on the evolution and characteristics of the ESW have been carried out based on particle simulations. The goal of this thesis is to develop one-dimensional and two-dimensional numerical particle codes which can be applied to the study of nonlinear evolution of electrostatic waves and instabilities. In particular, this study will focus on the electron beam instabilities and the formation of electron holes. By varying the parameters such as the ion beam thermal velocity, electron beam density, the mass ratio of ion to electron, and the electron gyro-frequency, we discuss the effects of the free parameters on the evolution of the ESW. The differences between the one-dimensional and two-dimensional simulation results are discussed.

並列關鍵字

electrostatic particle simulation

參考文獻

H. Matsumoto, H. Kojima, T. Miyatake, Y. Omura, M. Okada, I. Nagano, and M. Tsutsui, Electrostatic Solitary Waves (ESW) in the magnetotail: BEN wave forms observed by GEOTAIL, J. Geophys. Res., Vol. 21, No. 25, p. 2915-2918, December 15, 1994.

Jason R. Franz, Paul M. Kintner, and Jolene S. Pickett, POLAR observations of coherent electric field structures, J. Geophys. Res., Vol. 25, No. 8, p. 1277-1280, April 15, 1998.

Y. Omura, H. Kojima, and H. Matsumoto, Computer simulation of Electrostatic Solitary Waves: A nonlinear model of Broadband Electrostatic Noise. J. Geophys. Res., Vol. 21, No. 25, p. 2923-2926, December 15, 1994.

Takayuki Umeda, Yoshiharu Omura, Taketoshi Miyake, Hiroshi Matsumoto, and Maha Ashour-Abdalla, Nonlinear evolution of the electron two-stream instability: Two-dimensional particle simulations, J. Geophys. Res., Vol. 111, No. A10206, doi:10.1029/2006JA011762, 2006.

Y. Omura, H. Matsumoto, T. Miyake, and H. Kojima, Electron beam instabilities as generation mechanism of electrostatic solitary waves in the magnetotail, J. Geophys. Res., Vol. 101, No. A2, p. 2685-2697, February 1, 1996.