lnvariant imbedding theory approach to mode conversion in cold, unmagnetized plasmas
차가운,비자화된 플라스마에서의 모드 변환에 대한 불변 끼워 넣기 이론의 접근
- 주제(키워드) 플라스마 , 모드변환 , lnvariant imbedding theory , mode conversion , plasmas
- 주제(KDC) 420
- 주제(DDC) 530
- 발행기관 아주대학교 일반대학원
- 지도교수 김기홍
- 발행년도 2007
- 학위수여년월 2007. 2
- 학위명 석사
- 학과 및 전공 일반대학원 물리학과
- 본문언어 영어
초록/요약
In this research, we study the influence of periodic and random plasma density variations on mode conversion phenomena theoretically. We also study the interplay between surface plasmon excitations and mode conversion. For this purpose, we apply the invariant imbedding method to mode conversion phenomena in cold, unmagnetized and stratified plasmas, where the conversion from electromagnetic modes to electrostatic oscillations is induced by the inhomogeneity of plasma media. Ions are assumed to be static in the entire region and only electron density variations are considered. For various density configurations, we obtain unusual results which have never been presented before. At first, we investigate the case where the electron density varies linearly in the plasma medium and find that the mode conversion efficiency is strongly affected by the slope of the density profile. Next, we consider the case of periodic electron density configurations and find that the interference of multiply-scattered waves influences mode conversion strongly. We also study the cases where periodic or random density variations are superposed onto the linear profile. In the periodic case, we find that a complete mode conversion is possible when certain conditions are satisfied. In the random case, we find that the Anderson localization effect due to randomness affects mode conversion phenomena in an interesting manner. Finally, we consider the case where there is an interplay between surface plasma waves on the plasma boundary and mode conversion inside the medium. We observe that the mode conversion efficiency can be enhanced by surface plasmon excitations.
more목차
1 Introduction = 1
2 Theory = 7
2.1 Mode conversion = 7
2.2 Wave equation = 11
2.3 Invariant Imbedding Method = 12
2.3.1 Introduction = 12
2.3.2 Invariant imbedding equations = 13
3 Mode conversion with linearly increasing electron density profile = 17
3.1 Previous results = 17
3.2 Effect of the slope of electron density = 19
3.2.1 Model (A1) = 19
3.2.2 Results = 20
3.3 Inverse mode conversion within amplifying (gain) media = 23
3.3.1 Introduction = 23
3.3.2 Model (A2) = 24
3.3.3 Results = 24
4 Mode conversion with periodic electron density profile = 30
4.1 Effect of periodic variation of electron density = 30
4.1.1 Introduction = 30
4.1.2 Model (B1) = 30
4.1.3 Results = 31
4.2 Effect of near-resonance point (MCP) electron density modulation added to linearly increasing electron density: local range effect = 37
4.2.1 Introduction = 37
4.2.2 Model (B2) = 38
4.2.3 Results = 39
4.3 Effect of periodic modulation added to linear electron density : long range effect = 46
4.3.1 Introduction = 46
4.3.2 Model (B3) = 46
4.3.3 Results = 46
5 Mode conversion with random spatial electron density variation = 50
5.1 Introduction = 50
5.2 Model (C) = 50
5.3 Results = 51
6 Mode conversion associated with surface plasma wave = 55
6.1 Introduction = 55
6.2 Model (D) = 56
6.3 Results = 57
7 Conclusion = 66
Appendix A = 68
A.1 Derivation of s or p wave equation = 68
Bibliography = 71
