Experimental Study of the Dynamics in the Formation of Ultra
发布时间：2024-11-03 00:03
超冷等离子体是一种特殊的强耦合等离子体,其中离子和电子的温度远低于传统等离子体,因而其具有相对极长的演化时间,并且体现出强的库仑耦合效应。通过超冷等离子体研究强耦合效应还有许多优点,例如:等离子体初始状态可控、离子温度低而且演化时间尺度长、相对成熟的实验平台以及宽泛可调的参数空间等等。因而,超冷等离子体为实验和理论研究强耦合等离子体物理提供了一个特殊和理想的平台。本文主要研究超冷等离子体的产生动力学,实验通过激光电离磁光阱中冷原子的方法和冷里德堡原子自发演化的方法获得了超冷等离子体,并在两种实验方案中测量了不同条件下等离子参数的变化,重点讨论了超冷等离子体产生过程中起重要作用的物理过程和机制。利用磁光阱冷却囚禁的Rb-87原子的密度和温度分别为1010 cm-3和500μK。实验中可控制的物理参量包括:电子的初始动能（温度）、离子/电子的初始密度、里德堡原子能级和原子数布局、以及外加电场场强等。首先,我们利用光电离冷原子的方法产生了超冷等离子体,测量了等离子体的寿命和阈值离子数等参数,并利用库仑势阱模型和自相似扩散模型对实验结果进行了拟合和解释...
【文章页数】：103 页
【学位级别】：博士
【文章目录】：
abstract
摘要
Chapter 1 Introduction
1.1 Background
1.2 Motivation
1.3 Creation of an ultracold plasma
1.3.1 Photoionization of cold atoms
1.3.2 Spontaneous ionization of a dense Rydberg gas
1.4 Theoretical study of the ultracold plasmas
1.5 Recent advances in the ultracold plasma physics
1.5.1 Achieving strongly coupled plasma
1.5.2 Recent progress
1.6 Layout of the thesis
Chapter 2 Diagnostic techniques and plasma dynamics
2.1 Plasma diagnostics
2.1.1 Charged particle detection
2.1.2 Optical probes
2.1.3 Probing by three-body recombination
2.1.4 Other probes
2.2 Plasma dynamics
2.2.1 Three-body recombination and early electron dynamics
2.2.2 Disorder-induced heating
2.2.3 Kinetic energy oscillations
2.2.4 Self-similar adiabatic expansion
Chapter 3 Experimental techniques
3.1 Experimental setup
3.1.1 Direct photoionization of laser-cooled 87Rb atoms
3.1.2 Rydberg excitation and detection
3.2 Laser cooling and trapping
3.2.1 Magneto-optical trap
3.2.2 Vacuum chamber
3.2.3 Vacuum pumps
3.2.4 Laser system
3.2.5 Saturated absorption spectroscopy
3.2.6 Data acquisition
Chapter 4 Ultracold plasma from photoionization of cold atoms
4.1 Creation of ultracold plasma
4.1.1 Ultracold plasma with different ionization laser energies
4.1.2 The lifetime of the ultracold plasma
4.2 Ultracold plasma in the direct current field environment
4.2.1 Creation of the ultracold plasma in the DC field
4.2.2 Ultracold plasma with different initial electron kinetic energies
4.2.3 The dependence ultracold plasma on the direct current field
Chapter 5 Ultracold plasma from cold Rydberg gas
5.1 Rydberg atoms
5.1.1 Excitation of Rydberg states
5.1.2 Detection of Rydberg atoms
5.2 Cold Rydberg gas dynamics
5.2.1 Angular momentum mixing
5.2.2 n-mixing and ionizing collisions
5.2.3 Penning ionization
5.3 Spontaneous ionization of Rydberg gas
5.4 Evolution of cold Rydberg gas from n P states into ultracold plasma
5.4.1 Excitation and field ionization of the cold Rydberg gas
5.4.2 Field ionization spectra at different evolution time
5.4.3 Spontaneous evolution of nP Rydberg states
Chapter 6 Conclusion and future work
6.1 Conclusion
6.2 Future work
References
Acknowledgements
Personal Statement and Academic Achievements during the Doctoral Period
Appendix
本文编号：4010363
【文章页数】：103 页
【学位级别】：博士
【文章目录】：
abstract
摘要
Chapter 1 Introduction
1.1 Background
1.2 Motivation
1.3 Creation of an ultracold plasma
1.3.1 Photoionization of cold atoms
1.3.2 Spontaneous ionization of a dense Rydberg gas
1.4 Theoretical study of the ultracold plasmas
1.5 Recent advances in the ultracold plasma physics
1.5.1 Achieving strongly coupled plasma
1.5.2 Recent progress
1.6 Layout of the thesis
Chapter 2 Diagnostic techniques and plasma dynamics
2.1 Plasma diagnostics
2.1.1 Charged particle detection
2.1.2 Optical probes
2.1.3 Probing by three-body recombination
2.1.4 Other probes
2.2 Plasma dynamics
2.2.1 Three-body recombination and early electron dynamics
2.2.2 Disorder-induced heating
2.2.3 Kinetic energy oscillations
2.2.4 Self-similar adiabatic expansion
Chapter 3 Experimental techniques
3.1 Experimental setup
3.1.1 Direct photoionization of laser-cooled 87Rb atoms
3.1.2 Rydberg excitation and detection
3.2 Laser cooling and trapping
3.2.1 Magneto-optical trap
3.2.2 Vacuum chamber
3.2.3 Vacuum pumps
3.2.4 Laser system
3.2.5 Saturated absorption spectroscopy
3.2.6 Data acquisition
Chapter 4 Ultracold plasma from photoionization of cold atoms
4.1 Creation of ultracold plasma
4.1.1 Ultracold plasma with different ionization laser energies
4.1.2 The lifetime of the ultracold plasma
4.2 Ultracold plasma in the direct current field environment
4.2.1 Creation of the ultracold plasma in the DC field
4.2.2 Ultracold plasma with different initial electron kinetic energies
4.2.3 The dependence ultracold plasma on the direct current field
Chapter 5 Ultracold plasma from cold Rydberg gas
5.1 Rydberg atoms
5.1.1 Excitation of Rydberg states
5.1.2 Detection of Rydberg atoms
5.2 Cold Rydberg gas dynamics
5.2.1 Angular momentum mixing
5.2.2 n-mixing and ionizing collisions
5.2.3 Penning ionization
5.3 Spontaneous ionization of Rydberg gas
5.4 Evolution of cold Rydberg gas from n P states into ultracold plasma
5.4.1 Excitation and field ionization of the cold Rydberg gas
5.4.2 Field ionization spectra at different evolution time
5.4.3 Spontaneous evolution of nP Rydberg states
Chapter 6 Conclusion and future work
6.1 Conclusion
6.2 Future work
References
Acknowledgements
Personal Statement and Academic Achievements during the Doctoral Period
Appendix
本文编号：4010363
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