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系統識別號 U0026-1708201809433400
論文名稱(中文) 實驗室電漿中驗證朗謬爾波超連續頻譜的激發
論文名稱(英文) Experimental Verification of Langmuir Wave Supercontinuum Generation in Laboratory Plasma
校院名稱 成功大學
系所名稱(中) 太空與電漿科學研究所
系所名稱(英) Institute of Space and Plasma Sciences
學年度 106
學期 2
出版年 107
研究生(中文) 張皓
研究生(英文) Chang Hao
學號 LA6051085
學位類別 碩士
語文別 英文
論文頁數 63頁
口試委員 指導教授-河森榮一郎
口試委員-張博宇
口試委員-藍永強
中文關鍵字 超連續光譜  朗謬爾波  磁化電漿 
英文關鍵字 Langmuir wave  Supercontinuum  Magnetized plasma 
學科別分類
中文摘要 超連續光譜是將波入射光學介質藉由非線性效應產生頻譜的拓寬, 這個現象在不同的物理領域如光學, 流體和電漿等等都可以被觀測到. 這個現象存在一些工程上的應用, 如光學相干斷層掃描等等. 在電漿中朗謬爾波可以被非線性薛丁格方程式來描述, 非線性學丁格方程也被認為是可以用來描述光學超連續光譜的形成, 所以朗謬爾波可以產生超連續光譜是可以被預期的. 本論文的主要目地是演示實驗電漿中的超連續光譜激發, 在最後我們實驗設計在國立成功大學電漿所的磁化電漿腔將外加的縱向電場打入產生的電漿來激發超連續光譜, 因為外加背景磁場的關係,一維的設置可以被滿足, 在此實驗的結果, 我們整理成以下四點:
1. 我們成功由外加電場在電漿內激發靜電波, 並且符合線性的朗謬爾波色散關係, 所以這個結果可以說明朗謬爾波在電漿中被激發.

2. 激發波的相干長度為5500λ_De, 相較於線性朗謬爾波的朗道衰減長度~10λ_De是非常長的, 因此這可以說是非線性的朗謬爾波被激發的現象.

3. 激發出來的波有頻譜拓寬的現象, 並且在傳遞5500λ_De後拓寬的頻率 ∆f/f_pe ~0.1 且 相干性 ~ 1, 這符合我們對朗謬爾波超連續光譜定義.

4. 頻譜的拓寬跟激發器的打入電場的強度有正向關係.
由這些觀察到的現象可以說朗謬爾波的超連續光譜在磁化電漿實驗中有被激發,但是更進一步的探討可重複性和四波混和的現象對證明朗謬爾波的激發是需要的.
英文摘要 Supercontinuum (SC) is a drastic spectrum broadening of the initial pump wave caused by nonlinear interaction between the seed wave with the optical medium. It is widely observed in various fields, such as optics, hydrodynamics, plasmas, and so forth. There exist industrial applications of this phenomenon, such as a source of optical coherence tomography etc. It is well known that finite amplitude Langmuir waves (LWs) in plasmas are described by the nonlinear Schro ̈dinger equation, which is considered as a governing equation of optical SC phenomenon. Therefore, possibility of SC generation of LWs is highly expected. This study aims at demonstration of generation of Langmuir wave supercontinuum (LWSC) in laboratory plasmas. To this end, we have designed and conducted experiments, in which external longitudinal electric fields are applied to plasmas for LWSC generation in the MPX device at ISAPS/NCKU. A quasi one-dimensional configuration was realized by application of the background magnetic fields. From the experiments, we found the followings:
1. Excitation of electrostatic waves, whose frequencies and wave-numbers agreed with the linear dispersion relation of the LWs, was observed. The wave generation can be explained by excitation of LWs.
2. The correlation length (~ propagation length) of the excited waves was approximately 5000 λ_De, which is much longer than the linear Landau damping length 3 ~ 10λ_De, indicating that the excited waves were nonlinear Langmuir waves.
3. The excited waves showed a wide power spectrum, whose frequency broadening ∆f/f_pe ~0.1 and coherence ≲ 1.0 at the propagation distance of 5500λ_De, where f_pe is the plasma frequency. These satisfy our definition of LWSC.
4. The broadening of the power spectra was enhanced as the injection power of the external driver was increased
These observations indicate a possibility of LWSC generation in the MPX plasmas. Although further confirmation including its reproducibility, existence of nonlinear couplings of the waves, and so on are needed.
論文目次 摘要…………………………………………………………………….…..…I
Abstract………………………………………………….……....……..……..II
Chapter1 Introduction…………………………………………..……….….…1
Background of Langmuir wave supercontinum research…….….………...1
1.1.1 History of supercontinuum phenomenon research…………………...…1
1.1.2 Langmuir wave supercontinuum………………………...………….…..3
1.1.3 Purposes of this research……………………………………….……….3
References..………………………………………………………….....….….5
Chapter 2 Theory of Langmuir wave supercontinuum……………….………..6
2.1 Linear Langmuir wave………………………………………….….…...…6
2.1.1 Derivation of linear dispersion relation of Langmuir waves………….…6
2.2 Ponderomotive force…………………………………….…….…..………9
2.2.1 Derivation of ponderomotive force…………………………….....……..9
2.3 Nonlinear Langmuir wave- Zakharov equations…………..……..…..…..11
2.3.1 Derivation of Zakharov equations……………………..…...…….….....11
2.4 Nonlinear Schro ̈dinger equation……………………….….……......……15
2.4.1 Derivation of nonlinear Schro ̈dinger equation………………….……..15
2.4.2 Modulational instability………………………………..……..…...…..16
2.5 Langmuir wave supercontinuum…….…………………..……..…….…..19
2.4 Summary……………………………………….…………..…...……......21
References..……………………………………………….…..……….….....22
Chapter 3 Setup laboratory plasma experiment of Langmuir wave supercontinuum………………………………..………...…………...….…..23
3.1 MPX device……………………………………………..……….....……23
3.1.1 Vacuum chamber and pumping system………………………………..23
3.1.2 Magnetic coil system……………………………………………….….24
3.1.3 Plasma emitter…………………………....………………………….…26
3.1.4 Data acquisition system……………………………………………..….26
3.2 Langmuir wave exciter……………………..…..………………....….….26
3.2.1 Principle of Langmuir wave exciter…………………….…….…….….27
3.3 Measurement tools…………………………..….………………….….…29
3.3.1 Langmuir probe…………………..……..…….…….……………....….30
3.3.2 Double Langmuir probe receiver…………………...…………...……..33
3.3.3 Interferometer measurement……………………..………...…….….…35
Chapter 4 Experimental verification of Langmuir waves generation in plasma…………………………………….………………....................…….37
4.1 Target and idea of experiment……………………………………………37
4.2 Experimental setup………….……………………………………...……37
4.3 Experimental procedure……………………………..…………..……….41
4.4 Experiment result……………………………………............….…..……41
4.5 Discussion of results………………………...…..……………...…..……48
4.6 Additional experiment…………………………………………...……….51
4.7 Summary…………………………………………………..…….....…….60
References……………………..………………………….…..……….….....61
Chapter 5 Summary……………………………………..……..…………….62
參考文獻 R. R. Alfano and S. L. Shapiro, Observation of self-phase modulation and small-scale filaments in crystals and glasses, Phys. Rev. Lett. 24, 584–594 (1970).

R. R. Alfano and S. L. Shapiro, Direct distortion of electronic clouds of rare-gas atoms in intense electric fields, Phys. Rev. Lett. 24, 1217–1220 (1970).

C. Lin, V. Nguyen, and W. French, Wideband near-I.R. continuum (0.7-2.1 μm) generated in low-loss optical fibres, Elect. Lett. 14, 822–823 (1978).

V. Grigor'yants, V. I. Smirnov, and Y. Chamorovski, Generation of wide-band optical continuum in fiber waveguides, Sov. J. Quant. Elect. 12, 841–847 (1982).

B. Gross and J. T. Manassah, Supercontinuum in the anomalous group-velocity dispersion region, J. Opt. Soc. Am. B 9, 1813–1818 (1992).

A. Chabchoub, N. Hoffmann, M. Onorato, G. Genty, J. M. Dudley, and N. Akhmediev, Phys. Rev. Lett. 111, 054104 – (Published 2 August 2013).

Marek Trippenbach, Yehuda B. Band, and Paul S. Julienne, Optics Express Vol. 3, Issue 13, pp. 530-537 (1998).

A. Ting, K. Krushelnick, H. R. Burris, A. Fisher, C. Manka, and C. I. Moore, Optics Letters Vol. 21, Issue 15, pp. 1096-1098 (1996).

V. E. Zakharov, Collapse of Langmuir Waves, SOVIET PHYSICS JETP VOLUME 35, NUMBER 5 NOVEMBER (1972).

E. Kawamori, Generation of Langmuir wave supercontinuum by phase-preserving equilibration of plasmons with irreversible wave–particle interaction, Eur. Phy. J. D 72,63 (2018).

Y. Fujii, B. S. Kawasaki, K. O. Hill, and D. C. Johnson, Sum-frequency light generation in optical fibers, Opt. Lett. 5, 48 (1980).

F. F Chen - Introduction to Plasma Physics and Controlled Fusion, Vol 1: Plasma Physics, Springer US, 1984.

Dwight R. Nicholson – Introduction to plasma theory, Krieger, 1983.

V. E. Zakharov, Modulation instability: the beginning, physics D, Volume 238, Issue 5, 15 March 2009, Pages 540-548.

E. Kawamori, arXiv :1709.09113 [physics.plasm-ph] (2017).

E. Kawamori, Generation of Langmuir wave supercontinuum by phase-preserving equilibration of plasmons with irreversible wave–particle interaction, Eur. Phy. J. D 72,63 (2018).

Burton D. Fried and Samuel D. Conte, The Plasma Dispersion Function, Academic Press, London 1961.
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